2002 996 C4S - Coolant loss (AOS, Cracked Head, Gasket???)

I recently traded in my 986 Special Edition for a 2002 C4S with 105k miles on the clock. Car looks great for its mileage and age, it was very well cared for an came with a stack of service receipts. The car even had RMS, LN IMS, Water pump, and new clutch services performed. Now the car drives great, no obvious faults or concerns - great power and responsive delivery. The problem I do have is the following, coolant loss and a sweet smell emanating from the exhaust, not really coolant sweet but kind of like running rich sweet. I have searched high and low for coolant leaks and cannot find anything, no puddles on the floor and no drips. Considering that the exhaust has a sweet tinge to it I am relatively certain that some foreign fluid or gas is being introduced into the exhaust manifold and possibly the oil system. Other than those 2 symptoms I have nothing to go off of - no signs of oil in the coolant or coolant in the oil (checked coolant cap, coolant reservoir, dipstick, and oil filter.) I did try the AOS test of removing the oil cap while idling and the cap was kind of difficult to remove, much more so than when engine isnt running, it also sounded like the engine was struggling - RPMs dropped and were hunting to stabilize. So where does that leave me, I have already mentally prepared myself for a cracked head being the culprit. To give context to "coolant loss" - after filling up reservoir to MAX with distilled water it was a hair below MIN after a 10 mile drive. I know that the next steps are probably pressuring testing cooling system, leak down test, and compression test but is there anything else I can check to put my mind at ease? Can i be losing this much coolant with a bad AOS? Oh and speaking of AOS, when people mention AOS replacement are they talking about this part? http://cdn4.pelicanparts.com/techart...mall/pic01.jpg Thanks for the help and sorry for a long winded post Edit: Forgot to mention - no smoke on startup, engine temp is just a hair past the "8" on 180 but doesnt hit the "0", on cold start the rpms jump to about 1050 initially then settle down to 700-750.

The most likely cause is hair line cracks on the coolant reservoir. Usually at the bottom of the reservoir on top of the muffler so coolant just drips down and get burned directly without a trace. If you want to diagnose it yourself, just get a Stant pressure tester and pressure it to 21 PSIG and wait for at least 1/2 hr. Check for wetness by your hands and also by inspection mirror. The cap should also be tested or just replaced as a safety measure. Yes, the AOS is the bigger in the pic. A royal PITA to replace.

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Thanks Ahsai - the coolant reservoir is revision ending in 03 and the cap is 04, I was unable to find any traces of seepage from the reservoir when checking but I will do a pressure test to make sure!

To get a peace of mind, you may want to send out your engine oil for analysis to make sure there's no coolant in the oil. You can also syphon a cup of coolant out of the reservoir and place it in a clear cup to check for any trace of oil floating on top.

GT: My 2005 996 C4S was not losing that much water and at the start of smelling exhaust/cooling water after parking in garage no sign of water. However, Ahsai is right many times the leak does not make it to the ground. Also hard to see as the "normal" leak is on the back side of the tank and, of course, is buried in the corner of the engine compartment. Cap must be of proper type and just as important put on tightly repeat tightly. Check around the neck beneath the cap for signs of leakage. Ask me how I know...

This is where mine cracked on the 2003 C2. It is on the back, fender, side. I could smell antifreeze but never saw it. One day after a long drive I heard it sizzle on the muffler, still no drops made it to the floor. I got my bore scope out and snaked it between the tank and fender and then I could see droplets on the tank and residue on the "frame" rail underneath the tank.

FPB: Yep! Thats what i'm thinking.

Update: Rented the coolant pressure test kit and pumped up to 21 psi, left it on the car for roughly 45 min. After 45 min the gauge read 19.5 psi, so I lost a total of 1.5 psi over 45 min. At first, I didn't see any signs of a leak, nothing near the coolant expansion tank, nothing near water pump or any hoses in the engine bay or underneath the car. But then I walked to the front of the car and could smell coolant, sure enough the passenger side radiator was leaking coolant near the top and it was trickling down. So, now that i have identified A leak, what are next steps, is it possible I still could have another leak somewhere or would I have noticed it? Here are some pics of the radiator leak, how bad is it? 21 psi 19.5 psi after 45 min.

Good job diagnosing it! Looks like the radiator is leaking. Looks like time for the front bumper to come off to have a better look. Hopefully just a bad hose??

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Thanks Ahsai! Once I remove the bumper what am I looking for specifically, do I need to pull the condenser off of the radiator? If the cause of the leak is a hose, will I be able to get to it or will it be behind he radiator...any diagrams of the cooling system that shows hoses? Can this leak be what's causing me to smell coolant near the rear of the car, doesn't seem likely to me Oh and I forgot to post a pic of the car:

Nice 996! I think the best is to remove the fromt bumper and wheel liner and do the pressure test again so you can see excactly where it's leaking. It's always possible to have a leak at another place but you will just have to fix what you can see first and retest afterwards. For radator removal, this link should help http://www.pelicanparts.com/techarti...eplacement.htm For parts diagram, check autoatlanta porsche. To buy parts, try sunsetporscheparts.com

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Thanks Ahsai. I started the car today and let it run for a bit to see if I would be able to detect any more leaks at operating temp. When I was surveying the coolant expansion tank I noticed some fluid around the overflow collection rim of the tank...my cap is the 04 version, could I still be losing fluid via the cap?

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Might make sure it is tight!!!! Repeat TIGHT!

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So tight that I need to use both hands to unscrew it?

Yep thats how tight mine is! If it is tight then perhaps try a new one like Ahsai suggests. The drain for this area drips down past the spark plug coil area and may not make it to the ground. Could be your coolant smell in the engine area. P.S. once I got all my leaks corrected it took some time for the smells to completely go away.

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yeah I accidentally pulled the drain hose out through the engine bay and relocated it so I could see if I'm losing coolant. I think I'll buy another cap just to check the box, cheapest fix out there.

Worth checking there is no coolant leaking out from the bleeding valve. I had to replace my bleeding valve once.

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Thanks Shred, I checked the bleeder valve but didnt notice and leakage. I just did my first oil change on the car today, I didn't have a record of the last oil change and figured it couldnt hurt - I also wanted to see what was in the filter. Everything checked out, no sign of intermix at all. However, after the change I can no longer smell that sweet tinge to the exhaust gas - there's barely any smell at all, which is great, just not sure why that is?

I have been putting off the radiator cleaning for a while, been busy with work and haven't had a real window to attempt this item. This task was really two fold, I wanted to see if I could find any visible cracks on the passenger side radiator and I also need to clean out all the crap that was stuck on there. I followed a youtube video to help with the bumper removal, it was pretty straightforward, took about 30-40 minutes. Once I got the bumper off, leaves, dirt, and random **** just started falling off the condenser and rads. I don't think these radiators have ever been cleaned. Here are some pics of the radiator debris carnage. I plan on pressurizing the cooling system again tomorrow to see if I can identify the source of the radiator leak. I checked the hoses and they all appear to be connected - I'm hoping I don't have a hairline crack in the rad Bumper removal. Air vent removal, you can see the debris on the floor without even removing the air condensers. Passenger side debris, without condenser removal. Driver side debris, without condenser removal. Driver side after condenser removal and light wash - many of the fins are bent, not sure how much of an impact that has on cooling properties. Passenger side after condenser removal and light wash All clean!

Great job! And great pics!

I just performed another pressure test - results are not good...BOTH radiators are weeping. The passenger side is leaking from the top near the condenser screw fitting seam and the driver side bottom is also leaking near the condenser screw fitting. I can see micro fissures on both passenger and driver side. There is also visible corrosion on both radiators. I am guessing that my only real solution is to replace both rads, which would warrant replacing rad hoses, water pump (last replaced 6 years ago), thermostat, coolant (obviously), what else should I consider "while i'm in there?" Is the rad replacement a DIY job or should I bring it to a shop, any links to radiator replacement how to? Here are some pictures, may be helpful in diagnosing severity of the leaks: Passenger side leak passenger side top left radiator closeup of hairline crack Driver side leak driver side bottom right portion of radiator driver side bottom right portion of radiator driver side bottom right portion of radiator closeup of hairline crack

Unfortunately any leak of the radiator will require replacning the radiator. You really don't want to risk loosing pressure and getting the coolant to boil. For parts, you may want to check out sunset and rndeuroparts.com Also, it's the best time to swap out the ancient green coolant with the pink coolant.

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Thanks Ahsai - do you have a link to radiator removal and replacement or is this job better left for an indy? I just ordered an OEM water pump, thermostat, and coolant - do I need to replace radiator hoses as well?

There's a diy write-up here and it looks quite simple http://www.pelicanparts.com/techarti...eplacement.htm I doubt you need to replace the hoses but you should check by squeezing them one by one and feel if they are exceptionally soft.

Can anyone confirm if the 986 radiator pn is interchangeable with 996?

I believe that the Boxster 986 and Carrera 996 have the same 2 x coolant radiators. Genuine Porsche OEM are Behr / Hella Fits: Porsche 996 C2 / C4 / GT3 1997-05 Porsche 986 Boxster 1997-2004 Left: = 99610613151 Right: = 99610613251 If you want to go to a higher performance radiator (+/- 20 better efficiency) have a look at CSF who manufacture top notch stuff for competition use. They say their rads drop strait in with no mods required.

FYI, I have had really good luck with salvage yard parts. I would definitely go with new for the water pump but since the radiators seem to be an item that don't fail very often, it might be an option. And yes it's a fairly simple DIY. Just allow plenty of time and go slow. I can't remember if you have to remove the headlights but if so, unscrew them the least amount possible to get them out. If the adjuster comes off it can be a real pain.

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thanks Stephen that's what I thought as well but am getting mixed results when searching for the replacements. When I look up the p/N for a C4S I'm getting 996101613174 and 996101613272 - which seem to be turbo part numbers. Does the C4S share the same rad p/N as the 996TT? I can get a 986 radiator for about $80, just trying to confirm it will fit a C4S, seems like 996 base is a direct fit but the C4S may share parts with the 996TT. New AKG replacements are about $400 each. ​​​​​​the job looks straightforward enough, I will also be replacing the WP, thermostat, idler pulleys and belt.

Make sure the WP has the composite impeller and I highly recommend the LNE low temp therm.

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yup I got the pierburg with composite impeller and 160 thermostat with housing and gasket - both bnib for $250 off fleabay.

Off topic... Any chance you (or anyone on this thread) tell me the part number for the middle piece (see image) that mounts to the CS4 bumper? Thank you!!!!

Great thread! Thanks for sharing GTSilber!

I've started this repair and have hit a roadblock. I figured I would replace the water pump and thermostat while I was already flushing the coolant. I got the WP and stat out but it wasn't easy - some of those bolts are a bear, also extremely tight space and was using ramps so not the best scenario. I'm waiting on some WP bolts to arrive as well as engine mounts, mine started leaking when I jacked the car up. What's the best way to clean the mating surface, can I use wire brush to remove old gasket? I figured I would start on the radiators and see what I could get done. Here are my issues: 1. Driver side (left) wheel well liner - there is some fitting that i absolutely cannot remove, it is in a recessed hole and it is keeping the entire liner in place, does anyone know how to remove this damn thing? 2. Front wheel lugs are overtightened and I cannot get them free, since I don't have any coolant or a belt I can't start the car to turn the wheels - this repair cannot be done without removing the wheels 3. I have not found any DIY guide on this repair other than the Pelican article which is only like 6 pictures and not helpful at all, it seems the C4S may have a different replacement procedure. I got as far as removing the condensers but after that I'm stuck. 4. Please send help, I think I'm in over my head and too far into this to turn back

I think it may be a bit safer to just deal with the water pump and thermostat first then at least you can drive the car afterwards (to a shop in the worst case). You can use a copper wire brush to remove the old gasket and clean up the mating surfaces but don't be surprised if you cannot clean them out 100%. Usually you can't. You can follow up with a 1000 grit sand paper. As long as it's smooth and flat it will seal well. The permatex gasket remover will also help.

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I was hoping you'd reply Ahsai, thanks! To be honest, if I could get the front wheels off it wouldn't be so bad but I have limited access to the radiator hoses with the wheels there. I guess the fronts would be easier to remove if the rear wheels weren't on ramps, maybe I'll put the WP and Stat on then drop the car and try again. I don't plan on using gasket sealant for the WP and star but what about the bolts - should any of them be coated in sealant of loctite? In the event that I decide to let someone else tackle the rads, once I replace the WP and Stat, do I just refiil with a weak coolant solution like 1:5 or do I add the normal concentration, considering coolant will have to be flushed again.

You can filter the coolant and reuse it so it's ok to refill it to full strength. Are both front tires on the ground? If so, you may need to use a breaker bar and possible a handle extension to carefully get them to break loose. Also, try some kroil or PB Blaster and let it sit on the lugs for awhile.

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Yes both fronts are on the ground and chocked. I tried with a 1/2 24" breaker bar and drowned the lugs in PB. I used some 1/2" PVC pipe as an extension but the pipe pent, was planning on getting some steel pipe tomorrow.

Cool. It's annoying as heck when some shop or even the dealership over tightens the lugs. I've got a piece of metal conduit I keep to use as a cheater bar that's about 4' long and works pretty well.

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just went to home depot and picked up 1" 4' piece of steel pipe and then used as a cheater bar extension on my breaker bar...it worked, with a significant amount of force! These lugs were on so tight that there were loud metallic cracks when they broke free, they must've been tightened to 250+ ft/lb...idiots.

Scratch that, wheel lock key just cracked

That really sucks. I highly recommend replacing the lock lugs once you get them off. They are nothing but trouble. For the water pump, you will probably need to use a 1/4 driver and U-joint swivel if I remember correctly. On the front fastener you are having issues with, post a picture and we'll see if we can help. These cars take a lot of patience to work on. I've had 2 hour jobs take me a week. Between learning curve, prior owner mistakes, and being 12+ yo German sports cars, there are just a lot of challenges that arise along the way. I actually view it more like a video game though, each project is a level and there will be so many unknown obstacles I need to over come to finish it. It's only when I get in a hurry, or think it should only take "so long" that it loses its fun and I make even dummer mistakes than usual.

Just thinking on the broken lug key, I wonder if a machine shop would be able to sleeve and weld it for reinforcement. Might be quicker and stronger than ordering a new one.

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You need a good impact gun for the lug bolts and that's why I suggested fixing the WP first to make your car drivable. You can just drive it to a tire shop amd ask them to remove and hand retighten with a torque wrench for you. Then get some new lug bolts like Slakker said since the old ones may have over stretched. You can use a plastic filter to filter the old coolant and reuse before you can replace it with new coolant. https://www.amazon.com/Gallon-Strainer-Filtering-Biodiesel-Vegetable/dp/B00K9U5NNK The WP bolts should all be replaced with new (two are longer than the others). You also want to apply blue loctite on the bolts and use an inlb torque wrench (7.5ftlb or 90 inlb). Just be careful not to overtighten and break the bolts.

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Yeah I don't think the WP will be much of an issue, just need to take my time. I will definitely be replacing the wheel locks, guess I'll get some lugs off eBay to replace. Exactly, this shouldn't be THAT hard. I've done similar jobs on my other vehicles without some of the annoying obstacles that im running into now. I was hoping that I'd finish this job in a weekend now I've been tinkering with it for a week... I was going to use JB weld and a vice to see if that would work. It's cast iron so may be a more involved welding job? I should've listened, you were right Thanks for the link, just ordered. I have ordered new WP bolts they will be in next week. I've read mixed opinions regarding gasket sealant, I have both permatex WP and thermostat sealant as well as permatex # 2, or should I just install gasket dry to WP and thermostat? If there's a clean smooth mating surface I dont see the problem, thoughts?

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You're right. No sealant should be used. As long as you prep the mating surface like I said, the stock gasket is more than enough. Note the stock gasket is not flat. It will compress to provide a good seal.

I have a set of new OEM GT3 lug bolts for sale. They are 5mm longer than stock - not sure if that causes an issue when used without spacers? Anyway, they are heavily discounted from new Porsche prices and would be better quality than eBay parts. https://rennlist.com/forums/parts-ma...mm-spacer.html

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Got the thermostat and WP in place - used old bolts just to hold it in place for now.

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****ing amazing - was tightening a brand new WP bolt, one of the longer ones, and it snapped off. If anyone wants a 2002 c4s let me know.

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Heres the back of the pump you can see the bottom of the bolt protruding, and now there's coolant dripping from that area.

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​​​​​​After removing the pump here's what I'm working with, there's about 1/2" of bolt showing, can I try to cut a slit on the screw with a dremel?

I'd try to get a couple nuts on it and use a socket wrench to get it out. By chance did you put a longer bolt in there and it bottomed out? Good luck!

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When I removed the old bolts from the WP I put them into the new pump so I wouldn't mess up the placement. This bolt is one of the 2 longer bolts on the WP, unless the previous mechanic used the wrong bolt size on this hole I think the size is correct, it was also confirmed by Porsche parts department. I found this tool which I just ordered, hope this works, I've never had success with easy outs or left handed drill bits: https://www.amazon.com/gp/product/B0...A2ADIIKJ97TE1O

A pair of vise grip plier may work. You may want to use a thread chaser to clean out the hole after you remove the broken bolt. Just be very careful not to mar the mating surface. Are you using an inlb torque wrench?

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​​​pliers worked. Yes, using 1/4" in/lb torque wrench, I set it to 90 in/lb but it never clicked.

Nothing helpful to add. Just feeling for you, brother. Every repair I do seems to go along the same lines as your repair. The hard stuff - like diagnosing the problem is easy, and the easy stuff - like getting the wheels off and bolting up a new part - is impossible. Keep at it and keep posting. You will get there eventually.

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It really is frustrating, but in a weird way a challenge. The reason I choose to do most repairs myself is for the ability to better understand my car, the reassurance that the job is done correctly with the best parts, and to try and save some money. This job has made me realize a lot about this particular car and the complexity of the work involved. Tasks on the 996 require finesse and tact, brute force won't work... preparation and knowledge are the only tools you really need.

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Hang in there. You're absolutely right that one needs finesse, especially dealng with those small m6 bolts. You may want to check your torque wrench for accuracy. 90inlb shouldn't be enogh to twist the bolt head off like that.

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I think I need to start a separate build thread for mods - installed b&m ssk last night as well as fabspeed intake kit. Tonight I revisited the radiator as I'm still waiting for my WP bolts. Upon further inspection, I decided I could remove the passenger rad, with the wheels on, by removing the radiator housing bolts and then disconnecting hoses and sliding the rad out and underneath the condenser. I removed 3 radiator housing bolts, one on the inside wheel well, one near the center front bumper and one just under the lower radiator hose. After much manipulation I got the rad out with the fan still attached. I ordered new hoses but my current ones don't look bad at all, will still replace though.

I really doubt you need 90ft/lb on these screws, as far as I recall the oil pan required like 18f/lb on the screws, which is very low torque is required considering the part is already glued to the engine and that the engine is all aluminum aka fragile. May be someone has the manual to give the proper torque, I would say it is around 30ft/lb max.

90 inlbs not ftlbs. And the oil pan 7.5 ftlbs.

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90 ft/lb would be crazy on m6 bolts considering lug nuts are specd at 96 ft/lb!

WP and Thermostat are installed and hoses have been secured. Moving on to engine mounts next and then the rads. Are there any WP tests I can do prior to buttoning everything up to ensure there's no leaks?

argh I did not know there was such thing as in/lb ... learning every days thanks to you guys so 90 in/lb is same as oil pan 7.5 ft/lb, makes sense... sorry for the misinformation, my memory is a bit rusty, long time since I wrenched on my car. Are you going to do a "vacuum" before refilling with coolant ? I wanted to purge my coolant but the whole vacuum process scared me off.

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Ive read a bunch of threads about proper procedure for refilling coolant to eliminate air lock. Here's how I understand it: 1. Elevate rear of car and open radiator cap 2. Fill reservoir with coolant to neck 3. Remove oil cap and dipstick 3. Lift metal reservoir bleed tab 4. ​​​​Start car and turn heat on high 5. Run car at 2500 rpm until rad fans kick on 6. Check coolant level and top up as needed 7. Replace coolant cap, oil cap and dipstick 8. Drive car for 1 mile and check coolant level after, add coolant as needed and repeat until no more coolant loss Let me know if that procedure sounds correct.

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That's what I told her. Er, you.

GTsilber, IIRC that is the correct sequence for coolant fill up. I highly recommend getting your hands on the book 101 Projects for your Porsche 996 written by Wayne Dempsey of Pelican Parts, lots of good information in the book for those of us who are willing and able to work on our cars. I used that book for countless repairs including the Air Oil Separator replacement (which was a PITA) Don't stress too much on how long it takes, I always considered that to be bonding time with the car, great relationships take work!

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Thanks Mike. I actually just bought the uview 550500 which uses an air compressor to evacuate air from the system as well as fill up coolant, no mess and no need to worry about air lock! Peace of mind for $75!

Here's another coolant related question. I've drained the coolant from the car but how can I ensure I've gotten all of it out? Furthermore, my car currently doesn't look like it has P coolant as it's got an orange tint, now I'm worried about filling up with pink coolant and mixing the two...what to do?

This may help https://rennlist.com/forums/996-forum/737700-simple-3-step-complete-coolant-drain-updated-w-refill-procedure-water-pump-tips.html

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Where exactly is the hose in step 3, is it the metal line directly in front of the oil sump? Here's where I am after today: 1. WP and thermostat install complete 2. Engine mount replacement complete 3. New passenger radiator installed (bent quite a few fins) but still struggling with one of the hose clamps - I bought that lever actuated clamp tool but it broke after one use. Driver side top rad hose was not delivered today as scheduled so I need to wait. 4. Tried to fit new serpentine belt but my idler tensioner pulley is shot, just keeps spinning and I can't tighten it...joy 5. Pretty sure I drained my battery. when I put key in ignition I can barely read display but am seeing a bunch of failures (spoiler, airbag, coolant level, etc.)

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It's the hose on the passenger side right next to the sump plate. It's shown in the second last photo in the first post. The idle pelley bolt needs to be tightened (countered) really well using a wrench behind the pulley. Otherwise it will keep slipping when you try to crank the pulley to install the drive belt.

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Yeah I read about the dreaded 15 mm nut behind the pulley, really easy to access 😂 I'll try to get that done today. What do I do with my old radiators, WP, thermostat and hoses - does anyone on RL buy used parts?

Sunday update: 1. Tightened idler tensioner bolt and got new belt on 2. Finished the passenger side radiator install 3. Emptied remaining coolant from heater core 4. Pressure test FAILED 😬, water pump and thermostat are leaking, I think I'm throwing in the towel, what a punch in the nads

Is sealant used on the WP gaskets?

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I read that sealant shouldn't be used. I scrubbed off the existing until the mating surfaces were smooth and even.

GTsilber, I was going to ask if you used the black metal gaskets for WP and thermostat housing- but see them in the pics, so you are good there. Ahsai is right, no sealant is necessary or recommended. I wonder if you have a loose bolt. Did you check all the bolts to make sure they were tight to spec? I had a shop do a torque converter for me on my E46 and they forgot to tighten a bolt, and I had an oil leak. Super frustrating. Now, after I torque a bolt, I mark it with a sharpie or crayon. You are looking at removing both the WP and thermostat housing so you can clean the surfaces, and use new gaskets. What a pain. Sorry! You could have had a bad gasket or two. On the same E46, I had another shop in Waukesha, WI replace a cracked flex plate and install a new rear main seal. I asked for all old parts. I gave them all new parts to use from BMW. When they gave me the old parts, I saw a metal gasket in the bottom of the box. What the heck! The tech did not use the metal gasket for the RMS, and when I questioned the shop manager, he told me that the tech uses a German gasket sealant (silver in color) that is better than any factory gasket. Well, he may be right, but I would have preferred he call me before reinstalling the transmission. Good luck. You have a lot of courage to tackle this work. It will work out and you will be so happy you did it yourself.

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Hey sequel, all bolts were tightened to spec with blue loctite. I was very meticulous about the torque specs. All gaskets were brand new without any imperfections or creases. I've been doing this job in pieces over the past few weeks and I really thought I got it right this time, think I'm going to have it flat bedded to the pros. Thanks for the kind words of encouragement, I don't like to give up but I just really want to drive my 996 😃

GTsilber, might I suggest you remove the WP and thermostat housing, and ditch the gaskets, and use Permatex blue RTV? Just do a little research on using the sealant, and as long as you follow directions, you might be able to solve your problem. In a pinch without a factory gasket, Permatex is an excellent option, just look at all the testimonials of the stuff for oil pans, valve covers and WPs. When I have used it for oil pans and valve covers, I lay the sealant, then tighten about half way, just enough to get the sealant to squeeze out a bit. Then let sit for a few hours or overnight, then come back and tighten to spec. Surely folks will disagree with this recommendation, and I was skeptical of such, but read about it online, and there is a lot of support for using Permatex or another sealant.

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I had permatex #2 and permatex WP and Stat gasket maker and decided not to use it, read the stories and didn't want to risk it...Not saying that it can't work but I don't think it's worth the risk. Some people have had success and swear by it but the few bad accounts I read outweigh the positives. If the factory doesn't use gaksrt nor will I.

GTsilber, you might have a pin leak due to an imperfection on gasket, on the engine mating surface, or the new WP or thermostat housing is not machined flat. Using the same gasket, the same WP and the same t-housing will likely result in same leak. The nice thing about Permatex RTV that you have, it will resolve those stupid pin leaks if you have some imperfections present. You have progressed so far with lots of suggestions. I wouldn't throw in the towel just yet. The pros will charge you a pretty penny to take care of that leak. You can resolve the problem with a $3 tube! Go for it! (FWIW, I am not a mechanic, and am only speaking from my use of Permatex and dealing with similar issues.) Good luck my friend.

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Are you recommending RTV#2 or the thermostat and water pump gasket maker, two different formulations, the #2 doesnt harden. ​​​​ I shouldn't use rtv for imperfections on the engine mating surface correct? Pump to gasket is fine but gasket to engine is a big no no? I will most likely attempt one more time but I don't have the patience just yet.

That's a bummer. Provided the mating surfaces are smooth and flat, my suspicion is the bolt holes were not clean so they have too much friction. When the spec torque was applied, it's used to overcome the friction as opposes to compressing the stock metal gasket. I would remove the t-stat and WP, carefully inspect all the mating surfaces, use an m6 thread chaser to clean all the bolt holes, then use two new gaskets. Also make sure the inlb torque wrench is good.

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I will double check all bolts torque again tomorrow, all bolts (WP and thermostat) were torqued to 90 in/lb. It seems like the leaks are originating from the bottom of the gasket, or is that just gravity in action? While I'm at it, do you know the heater core rubber hose p/N, the small U shaped one that was disconnected in step 3 of your coolant flush guide? Edit: I think it's 99610623351

May be a bit difficult to verify torque with the loctite already cured hence my suggestion of starting over fresh. It looks like that elbow is 99610623351

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Does that mean I need to start with new bolts? Yes, I got the same p/N though I also found 99610623356 and 99610623355, are those older revisions?

You Tube Good video using gasket seal on WP w/gasket

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Good video but he used way too much gasket, this is really the only water pump replacement video out there for the 996.

I agree, just a thin layer should be all you need. Let it set up a bit before torquing. I was researching this just before you started yours, I am anticipating having to do the same. Just take a step back and catch your breath before you start over. You'll get it right!

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I would use a steel brush to clean the bolts good and check if the threads look ok. If they are, no reason why they can't be reused. You can also dry fit the bolts (w/o the wp) and feel if there's any strange resistance when screwing them into the holes by hand. All of them should be free to turn w/o resistance before bottoming out. The p/n I listed seems to be the latest for that elbow. No ideas about the other numbers you listed.

Is it possible you have one of the long bolts in a short hole? If so it may have bottomed out before compressing the gasket.

bummer, take a break and get back at it. It will be so much faster now that you have already done it once and it is fresh in your mind, you are going to go right through it. I remember I had a leak after replacing my oil pan, it was depressing as there is so much seal to clean up, but hey it happens. Keep in mind that if there is something finicky with the water pump it is unlikely that a pro will take the time to figure it out, unless you have a really good technician on hand, they just don't take the time to understand what is going on, and go right for the short term fix. No way they are going to take the time to clean the threads for example. you are almost there, and after that you going to be the water pump pro

I assume you used a new gasket? I agree that you shouldn't have to use sealant. If the mating surface is smooth and not scared you may just need to double check your torque values.

I have this exact issue with those bolts also. I had to heli coil a new insert in for the bolt that did break and it still seeps a bit that I have to keep an eye on the coolant level. it's very annoying. threw new bolts, every type of gasket at it and it still seeps a bit to this day. I am thinking it needs some gasket goop of some sort to get it fully sealed.

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Thanks Ahsai - I did dry fit the bolts and didnt feel any resistance when testing. I ordered the elbow from my dealer, first time it was cheaper than online No, the 2 long bolts are used on the holes with the raised mating hole guides on either end of the pump. Water Pump Pro - like the sound of that, let's hope that happens I will probably take one more stab at it but I am still on the fence about whether I should use gasket sealant or not, I am thinking yes. Yes brand new OEM gaskets were used, no visible or tactile grooves, ridges, or scratches - I really think its the bolts, will double check the torque values. Good to hear its not just me. Did you use new OEM bolts when installing, which ones in particular were weeping?

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I used new OEM bolts, torqued to the values in Jake's book. Exact same one you broke is weeping. Still is, but the coolant level isnt changing much at all. I know its weeping because I see the dry white remnants of a leak there. I can clean it up and that white remnants will be back...its obviously not a significant leak but needs to be addressed, I will probably tackle it in the spring

From your previous photo, the threads of the bolt seem to not match the threads in the hole. You see how polished and flattened they are?

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Yes, great observation. I got the bolts from the dealer here are the p/n, how should I proceed? 900 378 013 09 900 378 177 09

Those numbers were superseded by 900 378 013 01 and 900 378 177 01, respectively. If you type in these -01 numbers in Sunset's page here, you will see those -09 are older bolts http://www.sunsetporscheparts.com/oe...he/90037817701 I'm not saying the -09 are not good but I'm not sure what they changed. Maybe someone else knows. I would dry fit the WP (w/o the gasket) on the engine block and hand screw the two long bolts on and feel for abnormal resistance. Then dry fit the rest of the bolts similarly. If everything feels good, inspect the new gasket carefully and put it on. I would not apply sealant as you didn't have a leak with your old WP and there was no sealant used. That means your engine block and old WP were good. Your new WP is genuine Porsche so it's unlikely to be DOA. HOWEVER, do eyeball the mating surface of the WP and also see if the steel hollow dowels (for the two long bolts) look straight and not cocked. If there's abnormal resistance on the bolt holes, you will need to investigate if the threads are damaged. You can use a good chaser (don't skim here) and clean the bolt holes but be very careful as the holes are part of the engine block. Just use finesse and don't force anything.

I don't know if the thermostat cavity in your pics in post #50 show the final mating surface condition but if they do, it will need to be cleaner than that with no loose old black gasket material visible. The surface has to be completely flat.

This gives you an idea how clean they could be. I only used a brass brush and permatex gasket remover.

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Are those metal shavings on the top third of the bolt? Sure looks like some stripping took place...

I think those are bite marks from his pliers during extraction

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Interesting, shouldn't the dealer have caught the p/n revision change - strange that they can still order p/n that were superseded. The surface was flat with no raised areas or noticeable undulations. Maybe I didn't scrub hard enough but I think those gasket remnants were coming off with just elbow grease. That's impressive. I will pay for your airfare and per diem if you want to come to Florida and help me finish this install I should be banned from porsche ownership if I allowed that to happen Yeah - I'm going to refer to that as a reminder to always double check the torque wrench is calibrated.

Haha, thanks! You're doing fine. Just some temporary set back. Re the bolts, it's the other way around, you can only get the -01 ones from Sunset, who only sells the latest. If you type in the -09 ones, the page will automatically direct you to the -01 and says the -09 has been superceded. Not sure what your dealer did. Maybe they had some new old stock. I don't think your problem is the bolts anyway.

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The problem is user error, the mechanic is at fault!

I had some time to disassemble the WP and thermostat today, I got the parts off in about 45 min...Much easier second time around! I took about an hour to scrub off whatever remaining gasket was visible, I really didn't think it would come off but 90% did with a razorblade scraping tool. I then cleaned all the bolts in mineral spirits and removed the loctite. I then threaded all bolts with q tips and tried to get out any remaining gunk, there was plenty. I then tested all bolts in their appropriate locations and attempted to hand tighten each one, every single one went in smoothly except for the WP bolt on the bottom right, one of the long bolts. After about two revolutions I couldn't hand tighten any more, I ordered a thread chaser but I won't be here till after Xmas, what could be the cause of the friction? Oh yeah and I had another fun experience, since I haven't driven the car and have been working on it for the past 4 weeks, the battery went completely dead. Luckily my front bumper was off and I was able to use the frunk cable to release the hood. I checked voltage and it was reading 2.6V - I used an 8 amp battery charger and left it on overnight, managed to get the voltage up to 8.6. After another 8 hours it was completely charged at 13.5V. I now keep a battery tender on the car at all times...another lesson learned 😃 Merry Christmas and Happy Holidays to all! ​

I used to work with a printing company with a former business of mine. They tended to screw up orders on the first try quite often. We designated them with the following motto: "We get it right, because we do it twice." Seems like this may apply to you in this case. Hopefully your motto does not evolve into "The third time is a charm." GL

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That's the level of clean I was talking about That hole may have been damaged (stripped) by whoever installed the WP before due to limited access of that hole.

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Should I wait for the chaser to fix the stripped hole or do I just install the pump as is. Can a chaser fix stripped holes, or would that require a die set?

Before running a thread chaser or tap (as opposed to a die) into the threaded hole, get a set of round wire brushes from the auto parts store and clean up that hole. Looks to me like there is just some gunk in there. You need to be cautious about cleaning that up since it is part of the block. Start with the least intrusive method first.

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Thanks DBJoe - I have been using q-tips soaked in mineral spirits to remove a lot of the gunk but now that I think about it probably not the smartest object to stick into a hard to reach hole that's part of the block

Agree with Joe about using a wire pipe cleaner. A properly sized chaser should only clean but not cut the threads though but use with care for sure. Is there space to shine a light into the hole and see the inside? You got an endoscope?

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I scrubbed out the hole and got more crap out, checked with USB endoscope and it was good. Installed pump and thermostat, did pressure test at 24 psi with uview tool, no pressure loss and no drops. Boy was I ecstatic at this point. Filled up with coolant, approx 5.75 gallons. Buttoned everything up, installed belt, airbox etc. Started car, slight smoke at startup but thought that's typical for 3 weeks without a start. Monitor pump area for leaks, all dry! Let car get up to temp but noticed that temp was climbing very rapidly which is odd because I have a low temp thermostat. Engine temp was reading close to 200, I shut car off and looked underneath one more time, there's a leak, but not near pump - further up right in front of the headers near the engine. I've never seen this leak before and it's originating from high up but I don't see any coolant lines...Could it be an external crack to the block? This sucks, not sure how to proceed. Edit: wonder if the tstat didn't open and caused an increase in pressure upstream causing a crack?

Oh man, I was about to congratulate you on a job well done after your 1st paragraph. You did use the vacuum tool and the engine sucked in the full amount of coolant so I think you are safe. You can leave the bleeder valve on top of the coolant tank open for a few days when driving the car to bleed it further (after you fix the other leak). Re your new leak, the first photo was from the driver side looking up from the bank 1 tensioner. There are no coolant lines there other than the AOS's coolant lines. Is your second photo from the driver's side as well? If it is, the AOS is on top of the bank 1 scavenge pump.

Okay...was reading on my IPhone and wow! Got out the laptop to help. One - no way should you get to 200 so fast. Your thermostat is faulty and did not open correctly. I know it will suck to drain the coolant and check this again, but you have to. Agree with Ahsai, above on the drivers side is the coolant lines to the AOS. On the passenger side, the oil cooler O-rings could leak. But I think your immediate issue is that the thermostat is not working correctly. You are going to have to remove it and check it out. It is totally possible to have a faulty thermostat right out of the box.

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Yes both photos from driver's side. So I was thinking maybe I had a faulty coolant cap and it was spewing coolant down. I had a spare OEM cap and replaced it, also left bleeder valve open and went for a short drive - ballsy I know. Well, the temperature stabilized around 180 and never got higher, also no leaks or coolant loss in the tank. Could it have been the tank cap all along? How do I troubleshoot the AOS lines, I can't see any running up there? Gratuitous pic

That's great news! There's an overflow rubber tube that leads any overflow from the coolant cap to near cylinder #1 ignition coil. Anyhow, if there's no more leak, that's good. The AOS is way up high close to the top of the engine bay, directly above the driver's side scavenge pump.

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Update: Started the car this morning and the temperature gauge was flashing, assuming low coolant, filled up with distilled and proceeded to let car idle for 10 minutes. Temperature did no exceed ~160 and I couldn't observe any leaks, smoke, or other paranormal symptoms. Decided to take her out for a spin and see if I could get her up to temp, I drove pretty hard for about 40 minutes and never got above 180, radiator fans never kicked on...At this point I'm assuming I don't have any leaks, though a very minor leak could be possible and I just can't see it. I'm still suspecting the coolant cap was bad from the start. I actually never replaced the driver side radiator, will be bringing in to an Indy. I got rid of the pumpkins and installed some smoked side markers, think they look great. I will continue to monitor for leaks or abnormal signs and report back. Merry Christmas and Happy Holidays to all 😀 Freshly washed!

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Here are some additional pics of the AOS area, you can see dried coolant on the AOS. I have not observed fresh coolant leaks since that initial discovery, but if there was a leak at one point it's likely still there. I can't tell if the hose backed out or if there's another source. Driver side in front of cross member looking up Link to AOS oil cap test, there is significant pressure present when removing cap, idle also changes dramatically - I believe AOS is bad: https://drive.google.com/file/d/0B0m...w?usp=drivesdk

Still wondering if I may have an AOS issue. I can't see any more leaks but the AOS area in front of the headers is extremely hot and may be burning any slow seepage. Based on the video and pics I posted above can anyone provide recommendations or analysis?

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The engine changing sound with the oil cap removed and a slight vacuum are normal. You really need to use a manometer to check for the crankcase vacuum to diagnose the AOS. I suggest you clean the AOS area as much as you could. (e.g., with a garden hose spraying up) so you can see the stain if it leaks. Is your coolant level dropping?

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I don't see a noticeable drop in coolant, however, my coolant level is always a few mm below Min when cold and rises above min when hot.

Started up the car this morning and checked under the chassis, saw a small amount of coolant on the floor and drop forming at the lowest point below cylinder 1 - it's a large nut not sure what it's called. But you can see coolant has been collecting there, whitish residue on the nut. I'm pretty positive either my AOS coolant nipple is cracked or the coolant line connecting to the AOS is cracked. At any rate, AOS needs to come out, a job I'm not willing to tackle myself due to timing. Here's a pic, : What is the circled part called? Notice small drop forming, must be leaking from above and when engine gets to temp it's burning off so I never noticed it.

That's the bank 1 timing chain tensioner.

The saga is finally over! Brought my car to an expert Porsche mechanic and told him exactly what I've done and where I think the problem is (AOS.) Asked him to install the driver radiator, hoses, and replace AOS. Picked up my car today and sure enough the AOS coolant nipple was cracked and you could see the white calcification on the AOS...Glad I left the job to a pro, feel much better about it and don't have to second guess my work. Turned out my radiator fan was also kaput so that was replaced as well. In addition I had new rotors pads and a brake fluid flush done...All said and done 8 hours labor + new rad fan, and I finally get to enjoy my car again ​​​​​ Thanks to all those that helped along the way, much appreciated

GT: thank you so much for sharing your journey, knowing your limits but willing to keep trying. Very inspiring and one I greatly appreciate!

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Your welcome Brad, thanks for reading! There's so much information on this board and in an effort to keep the dialogue flowing and the content rich and original, I shared my experience with gusto in the hopes that one day someone will find this thread and be able to diagnose an issue or at least take away a nugget of wisdom.

Glad to hear you are up and going again. Enjoy!