AOS/OVS Leaking Coolant! Drop Engine?

Last night I saw the dreaded coolant leak from the #3 area, inspected from below and can see a tiny pin hole coolant spray leak from one of the AOS coolant lines/connections. Guess its time anyway at 58,000 miles. What sucks is that a few months ago I had the trans out for the IMSB, clutch, etc. and probably should have done it then for PM. My question for you guys is should I just drop the engine and do the other things too (water pump, T-stat, hoses, etc. (engine detailing!) or replace from the top? Please feel free to make suggestions I just didnt feel like doing this so soon after the trans drop so cheer me up. My wife is now officially referring to the 996 as "the money pit" which I do somewhat agree (cant wait to post my 1 year of ownership parts replaced list).

Drop the engine and change everything you can KK. Then send all your parts to my house haha. No joking apart. It all depends on if you DIY and if you have the time and money available to do what ever you decide needs changing. I for one love working on my car. I have the time and the money and if I could, would have that engine out in a heart beat and change everything I felt a need to change. I am retired with lots of free time on my hands. Taking the opportunity doesn't add up in my mind if it doesn't need changing. PM can be taken overboard and from your posting and the 'money pit' statement from your wife, I would only do the stuff that really needs doing. Don't let 'could have' or 'should have' sway your decisions. How were you supposed to know something would go wrong? WE are dealing with teenage cars and teenagers can be so temperamental. PM can be a guessing game as several posters have confirmed. ie (bearings changed and nothing wrong with them. Not one or two but almost every one I read). The same with water pumps, AOS etc. I mean where do we stop? Repair the stuff as it happens and don't be too hard on yourself. You are not a psychic for Gods sake.

KK - you're thinking you have to now drop the engine and replace everything...over a pin hole coolant leak from a hose? Do yourself a favor, identify the hose and just replace it. You gave no indication of a bad AOS so why go through all that? I know you love to tear your car apart and do stuff, but to me if the wife starts complaining it is time to give it a rest and pay more attention to her!

First off I'm pretty disappointed in you. This has been like your second slip up within a month(not replacing those ugly rotors, your first). Secondly if you are gonna drop the motor, do the rest as you mentioned. That way your nice clean tranny will match the engine. As for the wife give her the same scare speech you give here. If you already told her, remind her again that you'd rather spend a little now than a lot later.

I'm just shocked he hasn't replaced his wife.

yes, I would change all the parts mentioned, when its time to change the newer parts you will have the older parts as spare... parts price are increasing on these machines, so you are already saving money keeping your old parts. little trick I learned from these boards....

You should tally the amount of hours you spend driving this car vs. working on it/posting about it.

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Good point. Between working on your car and posting here on these forums, how is it that you're even still married? And don't tell me she's a quiet gal but has a big mouth.

So it seems most of you are inclined to drop the engine for the AOS and take care of the other issues at the same time. Thats what I'm leaning towards doing as well. Theres no big hurry and it will give me a chance to seriously clean and detail the engine. For reference, look at the diagram below (older style). I suspect that the plastic nipple where hose #13 connects is the culprit. The nipple probably has a pin hole leak/crack and may even break off soon. Really poor design IMHO.

Good lord........

I considered not replacing mine even though I had the transmission out and the part in hand, just because it had no problems with it so why replace it. I decided to tug gently on the hoses and when I did the coolant nipple snapped off in my hand - the plastic was very brittle. So I had to replace it anyway. Words are incapable of describing how badly that job sucked...

Yeah, I live for opportunities to "seriously clean and detail the engine."

I take off my rotors and clean the insides and also between the vanes when I wash my car. I'm hoping one day I can take out the engine too to give it a good clean but that's a little more involved. I was slacking the other day though as I didn't wipe off my wiper blades after I used it in the rain.

you used your car in the rain, and with the wipers on.... good lord!

Part of me really wants to drive to TX to see KK in person. From his posts, it seems he never drives his car and despite never moving his car is constantly being "fixed". He must be busting the ***** here. Cleaninig engine on 996? Because it is always in full view with trunk lid open? Or, his car is like an under-fooked beautiful woman. She never gets taken out, she never gets sweaty and dirty, and she never feels like she was manhandled to the point of passing out. So, naturally she is bored beyond belief and engages in passive aggressive sabotage. Now when KK gets tired and sells the car, he will wonder why all that PM and care didn't pay off (nice guy syndrome). While his car will go to someone who abuses it, drives it weekly for 500+ miles and never bothers with washing it more than once a month. Next owner will have no issues until 300k miles and will thank KK for the gift.

You know you can just lower the motor & trans to get to the AOS right?...

If YOUR car was sitting in your living room on your clean carpet, you would make damn sure you had a clean, non leaky engine. KK's threads are usually epic. I will miss him when he trades in his 996 for a Toyota.

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I don't have that problem. This is where my 911 sits....

^^^^ Nice. Can you even tell which oil/coolant spot would be from your car if you had one.

He can't trade the 996 in for a Toyota... dropping the engine to clean it will void the warranty, so there's really no point in buying a new car. OTOH...can you imagine the service writer's expression as the new Camry owner is explaining why the lug nuts, due to the inconsistent chrome plating, are clearly defective and in need of warranty replacement?

Yes, but several of the posters who have changed theirs said they would drop (remove) the engine next time. Now cmon guys who doesnt appreciate a nice clean 996 engine? You do realize that if kept leak free, it stays fairly clean? My lovely wife is trying to convince me to take the easy(easier?) way out and not drop the engine/trans. Wheres the fun in that? How the hell am I supposed to detail the engine? Also got my 997 shifter sitting there waiting to be installed, then this happened. I must admit, it just never ends with the suspense of the next 996 PM or failure issue! Great learning experience.

Toyota would be a no no for KK. If he's this paranoid about IMS, what will he think about the inintended acceleration problem that has plagued Toyota recently?

If you leave it dirty, the clumps of dirt that accumulate make it much easier to find the leaks. Sh*t, man, I evaluate the health of my Corvette based on how long it takes me to clean up the oil spots on the garage floor every other weekend.

You can just clamp the coolant lines and be done with it. Not like you'll be driving in the winter anyways.

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Nice parking spot Kalish. The Porsche blends in really well when you get south of Thomas Rd.

Subscribed. I feel like this thread has the potential to become epic, but it needs more *****...where's Gator with an awesome, well timed pic? KK, no matter what anyone says, you're itching to drop the engine...so drop it, fix/replace everything that bolts on or off, detail the **** out of it, take lots of pictures (but size them to fit this time please) and put it all back together, and then let us know how poorly made these cars are, and let us know when you move it to the living room for it's final resting place. Also, when you are putting together your tally for first year of ownership, you need to have two columns, or totals..."HAD to be replaced due to actual failure", and "OCD took over and I couldn't help myself and replaced it because it may/could/should/might/I heard about it once on RL" type of failure. GL with replacing the AOS, looking forward to the write up and subsequent pics. DS

KK - got your caliper stickers....thanks so much. Going to hit that job up after the holidays. Regarding the major project - whatever you decide, I agree with DS - keep us informed and give us pics. My car is my daily driver....so, she does not get a rest for a deep clean...she always shines - that's easy - but, dropping the engine and detailing.....maybe when I am Hurdi's age - HA You go with your bad self - thanks again for the stickers. You are a Porsche saint!!! Ray

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St. Krazy, the patron saint of gratuitous maintenance. "Ab absurdo, a IMSB usque ad AOS" - St. Krazy of Tejas

Well OK, but on a serious note, I think I will document and photograph things along the way just in case I find something different about my method than the 1000 DIY writeups for engine/trans drop. Whats even stranger about this, is that now my wife is suggesting dropping the engine for the ordeal. Maybe shes going to "accidently" knock the car off the jack stands?

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Tell her my $20 is in the mail...........

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Not worth the risk of her getting hurt in the process. When she's sick of you and actually wants to go through with it, she'll start mixing small amounts of all the fresh coolant you've drained on a monthly basis into your drink or food until you start getting sick and the doctors can't figure out what's going on. :devil:

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You guys are underestimating two important things here, KK's OCD when it comes to his 996, and Mrs. KK's understanding of said OCD. If she wanted to kill him, she would take the coolant, and periodically put some in a pool in various locations under the car...as well as a little oil just to make things interesting. A month of this and we would be remembering KK as a well intentioned guy that once graced our forums, before his simultaneous aneurism/heart attack/stroke/spontaneous combustion got the better of him. DS

When I did mine it was a right PITA. I diassembled the top of the engine and lowered as the guys had mentioned. You can then access the AOS (I changed the o rings on all the aos fittings). The problem I had was the rear bolt on the AOS had siezed, the one nearest rear of car came out no problem. I ended up dremelling the head of the siezed bolt off. I then removed the AOS and used heat and a stud remover to get it out (the kind thats a bit like a drill chuck). What's required is straight forward, working in the tight space for a long period is frustrating, if you have a problem.. I had bruised knees from kneeling behind the car for a day!!! If you do need heat like I did, make sure you find something to protect the fuel lines and sound insulation (I used some old heat shields. If you have other things you plan to do, I'd drop engine if I was you to change the AOS, if you just need to change the coolant pipe, I'd just do that and leave the AOS till you have the engine out. The coolant pipes go into the top of the AOS so should be easy enough with the engines lowered a little and near side inlet manifold off. Good luck!

yup... not a fun job. the newer one had a better seal to the engine.

Oh yea the 2003 has a different AOS, it doesn't bolt on the side but from above, it doesn't have the bellows it push fits then bolts down...

def an over-engineered hunk of plastic and rubber... an old $5 PCV valve would of done the job... and would of still leaked.

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Ah, KK has nothing over me on that one! I had a cat go bad, so replaced everything including headers all the way back to tips, all four O2 sensors too, just because they were old. Did the LN IMS, RMS, replaced AOS, water pump, fuel pump, spark plugs, hoses, front rotors, yada yada yada. Replaced the OEM radio with double-DIN satellite radio/telephone/navigation system. Even got a new set of center caps because one of the old ones was a bit discolored. Oh, and a new cigarette lighter (even though I don't use it) because the little cigarette icon on the front was worn and it bothered me. Yesterday, I ordered new leather because my driver's seat is worn on the bolster. Money pit? Sheesh. I've spent more on PM than I paid for the whole car. But, I'm loving the car anyway!! I enjoy each and every drive more than you can imagine. At least KK has time and space to work on it. I have neither, other than for the minor stuff I can get to without an engine drop like fabricating eucalyptus wheel spacers and brake pads). So, my indy prolly can buy himself a new 991 on my dime.

KK, a serious question. Have you considered a Ferrari? I heard those are great cars but needs tons of repair and PM, engine out to boot! Seems even better than a Porsche for you?

Cuda, that really sucks. I just thought I had it bad. Strange you say that because my next one may be something like a Ferrari 430 coupe even though my wife wants a Maseratt GT. Both sound like a blast to work on. I would like to keep the C4S though I dont know why, and add a TT or GT2 instead. My project would have been finished today but apparently "overnight" shipping means 4 days for FedEx. I would like to thank all for the great DIY's and tips!

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Oh yeah, as soon as I got my 996, I also replaced the swing-up garage door with a new overhead track door and belt-drive opener. Once I had an old spring break on a swing-up garage door and a chunk of the spring flew across the garage and made a huge dent in one of my cars. I keep looking at Ferrari's and Maserati's too, and plan to get a TT some time in the next year or two. And I'll keep the C2. New door:

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I have a 2002 and it bolts from above. The only way to remove it was with the transmission out. The AOS blocks the rearmost bolt on the intake making it impossible to fit a socket on it, so I had to remove the AOS from the flywheel side. The AOS bolt next to the intake was blocked by the hoses above and could only be removed from the flywheel side with a 1/4" drive ratchet and a deep socket and then only a couple of clicks at a time. I ended up removing the intake after the AOS was off. I then installed the new AOS and connected all the hoses, but to install the intake I had to loosen the AOS bolts so it could be tilted back enough to allow a socket to fit on the rearmost intake bolt, then retightened. I'm also doing the RMA and IMS and so much has to be removed the only thing left to pull the engine is to disconnect the fuel line, electrical cables, and coolant hoses and the engine falls out. My advice is to remove the engine and be done with it. I will never attempt to do such in-depth maintenance again without removing the engine - it's just not worth the frustration. The 996 is engineered to be assembled and to run, but to perform all but basic maintenance one has to peel back each layer of the onion until arrival at the part to be replaced, and each layer has a specific sequence and procedure that must be followed to remove it. If that wasn't bad enough, after the engineers designed the motor they stuffed it in a hole so it was impossible to reach anything...

On the 02+ 996, you can loosen it with a 1/4 drive socket and extension then finish taking it out with a stubby open end until you can remove with your fingers. It can be done because I just did it. It also helps to have the coolant tank out of the way. I agree, removing the engine is easier. I just did this before dropping the engine to see how hard it really is. The new style coolant tank was a real blast.

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It's not easy but you don't have to drop the gearbox. I guess you need nimble hands though. I got it with a short spanner from the side in combination with a socket on a small ratchet (using a couple of extentions you'd normally use for screwdriver bits. I did it all by removing the intake manifold and lowering the engine a few inches...

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No it wouldn't have done the job.

I just wish all the nice cars had the AOS in an easy accessible location. I haven't come across any yet where you don't have to drop something, have small hands that can contort, take off half the top end, or make your own tools. Oh, it would help if manufacturers wouldn't use plastic as heat and cold will make them brittle over time. I'd rather have rubber swell at least from the hot oil than plastic break. Of course manufacturers like BMW does use some rubber hoses but they tend to break at the hose clamps since the hoses are usually a few mm too short and under constant strain from the movement.