Need some Advice: Coolant Issue

I looked in the engine compartment last week and noticed that there was a little dried up coolant around expansion tank cap. It wasn't there when I bought the car, but I did remove it once before winter set in to check the anti-freeze protection level....verified it was a 50/50 mix. Here's a picture of the OLD cap, which was a 00 suffix, probably the original cap on the car. So I ended up buying a new cap with the 04 suffix, and yesterday I installed it. The coolant level was between low and high when I put it in, I added a few ounces of water just to make sure the level was there, the car was somewhere between stone cold and operational temperature. The coolant level was 1/2 way between low and high. I tightened the cap very tight by hand and let the car sit over night. Today I drove the car up to a car event, let it sit there for a few hours, drove the 20 miles back home and put it in the garage. I drove spirited, but not hard by any means. I am probably just thinking I smelt smells that I normally don't smell when I was the last 4 miles from home, which are on side streets vs. highway. After about 3 hours, I took the car over to Home Depot, a few miles away, drove it back home and when pulling in the garage I noticed a leak on the garage floor. It appeared to be coolant, sweet smelling, definitely not oil, and there was a few ounces. Here's a picture AFTER I wiped it up. The garage pitches towards the garage door. I placed the car where I thought it would be the last time I pulled it in for this picture. You can see it's really close to the exhaust, or maybe just in front of it, but appears to be in line with the left exhaust pipe. NOTHING has dropped out of the car since my return trip from Home Depot, I put clean carboard under the car and there is nothing on it. NOTE: I have a lot of clear coat materials on the garage floor, that's from wood working projects, the area that appears to be wet is the area...the other spots are varnishes that have cured on the floor. And here is the expansion tank cap (new one, 04 suffix), you can see there is no coolant leaking by it. The little bit on the right was not cleaned up yesterday. When I first figured this out, and the engine was still hot, the level was below "min", but still on the part of the reservoir that sticks out, so it could be read below the "min". Now that it's an hour or two later, it has dropped down below the shelf part of the reservoir. But you can still see the coolant in the main reservoir section. I have not cracked open the cap, it is still a sealed system. What do you suggest that I do? I don't think it's coming out of the exhaust, but anything is possible.....I was going to let the car cool down and then start it up and see if anything comes out of there. It does appear that there could be coolant leaking down on the left side muffler, I don't think it's salt left over from my ride home from Reno, NV last year. I cleaned the heck out of the car since then. The right muffler does not show anything leaking on it, so if it was salt, it would be on both mufflers. Thanks for you input.....I figured I would post before I do anything else.

BTW, the oil level is full (changed it not more than 500 miles ago) and perfectly clean. The oil fill tube is clean also.

Looks like the typical coolant tank leak. Your tank looks quite yellow so it may be on borrowed time already. You can try to use an inpsection mirror to check the bottom and back of the tank and see if you could see where the leak is coming from after a spirited drive. If you can't see any leak, you will need a pressure tester (e.g., Stant) and an inspection mirror to diagnose it further.

Paul: I had similar situation first drive this spring. Had put a new 04 Blue cap on replacing the old Black Blau version as a preventative. After driving up to temp and enjoying for a few mile brought back to garage and smelled anti-freeze. Yep, small puddle beneath left side muffler. Difference is I opened hood and noted water spewing out from underneath new cap! After cooling pulled new cap and reinstalled old one. No problems since. Two things: #1: I think I did not tighten new cap down enough as seating ring did not show that it had been seated all the way around. #2: The insides (important parts) have the same part # which is manufactured by Blau! Question: How old is your tank? Mine was leaking in same area before it was changed last year.

Ahsai- Thanks...that would make sense as the ride home today from the car show was very spirited on the highway and the new cap was the leak by point before. Guess I will need to sort this out before my upcoming track day on 5/18. I'm trying not to be paranoid! But it is hard! I feel better already. Paul

P.S. leaking tank is very hard to see! Mine was cracked in back up high near seam and was not very yellow!

I am almost sure my tank is the original tank. And probably the water pump and serpentine belt. It's a slippery slope!

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Welcome to the club Personally I would get that tank changed. The polyrib belt is a 30 minute DIY. Now lets talk about that WP......

My guess would be the tank too, all it takes is hair line crack. Also it's not uncommon for these to leak on most German cars. -Jason

Second Pete's suggestion especially since you track your car.

Tank on order, for now I just topped the reservoir with about 12 oz of water and put the old cap back on. Also ordered a serpentine belt.

If you need to order any other parts, I'm offering 10% off for Rennlisters on all parts currently on the website. Contact me if you're interested. -Jason

That was exactly how my tank started leaking. I replaced my cap, due to seeing a little coolant around the edge of it. It was the old part #, and I was smelling coolant after a drive although nothing was dripping onto the floor. Within a couple of days after the replacing the cap, the tank started leaking about the same amount as yours.

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The new cap creates a better seal and higher pressure on an old tank.....that is what brought the leak.

That makes sense....the tank looks yellowish......

If you need a hand Paul, let me know!

The new expansion tank can't get here fast enough.....now when I drive the car, even though the level has changed, I can smell coolant when it warms up. She will remain parked until I fix it.... Bring out the turbo!

Paul: While I understand the paranoia, I had antifreeze smell for sometime after the tank change as well as the cap fiasco deal. Seems it takes a "few" drives to burn all that stuff out. Must be in areas that take some time to get hot enough to get it evaporated.

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Paul just experienced something similar. Replaced the coolant tank and top and have had no issues since. Sent from my iPad using Rennlist

Ditto Pete and others. Likely the tank is causing the leak. The water pump and thermostat combo isn't a bad DIY job - I'm no expert mechanic and have tackled them both (with a full coolant flush and other related items) in the last few months. Just wrapped up a very fun and intense weekend on the track too with no leaks, issues, etc... You'll be all good.

Just did the coolant tank replacement on my 03 996 two weeks ago. The peilcan parts article is misleading. They state that you have to lower the engine (via the rear mounts) to get to the tank on the 996 C4 and the convertible because of other bulk items in the way but you probably don't have to lower the engine on the C2 coupe. There is no way that big a** tank is coming out without lower the engine. Oh, do yourself a favor, once you lower the engine, remove the brass cap at the end of the fuel rail that is in your way. very few instructions mention this cap but it is directly in the way (for the installation) of the bottom/side opening of the tank.

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Agree it's a bitch on a MkII. His is a MkI and it should be a lot easier to remove the (smaller) tank. He probably needs to remove the fuel filter though.

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You are 100% correct. The early 996 Carrera had a shorter coolant reservoir and did not require you to lower the engine. The later version of the coolant reservoir was much longer and DOES require you to lower the engine. The years were left out because there were exceptions to the rule for C4 and Tiptronic. Apologies for the confusion. Thanks for your suggestion as we will have that updated in the tech article. -Luccia

Changed the coolant tank out successfully, was a pretty easy job. Very soothing to be in the garage away from the computer which I am on all week for work. Okay, so it was a cracked tank, glad I didn't drive it any more after finding out there was a leak. Interesting level detector: After using channel lock pliers to get the hoses off, I knew there would be no way to get them back on the same way, did a quick google search for some hose clamp pliers and found these.....over to Sears and picked it up.....OMG, the best tool ever! Makes child's play out of the hose clamps. You engage it, the tool locks, position it, then unlock the tool and it releases. I lowered the engine to get the coolant tank out, considering how easy it is, why not? I did try to get it out without lowering, but it wouldn't come. And I wish I had a new fuel filter when I did this job....weird place for a fuel filter! The only issue I had was that I put back in 2 liters of coolant at the end of the job. It went to "Min level" and then as it heated up it went up.....drove it, and when I checked it, it dropped down quite a bit (no coolant warning light), parked it and let it sit over night. This morning I put about 750 ml into it, put the cap on it, then drove it to get some heat into it. Now when it's warm it's at max level. I was so PARANOID yesterday that I drove it with the heat on HIGH because the temperature gauge would show the right hand side of the "8" and go to over the left hand side of the "0". This morning I verified that it sits on the right side of the "8" after a hard drive. However, when the car idles, it drifts up to the right side of the "0". I let it idle after a hard drive for 5 minutes and it drifted up, then in neutral I rev'd the engine to 1500-1900 RPM for 30 seconds and it started coming back down almost immediately. So I'm going to say this is normal because the water pump is running fast enough at idle. The AC was on, so the cooling fans were also on (even though I did not verify air flow). Thoughts?

The temp gage is severely dampened. If you want to know what the coolant temperature is doing you need to connect an OBD2 code reader/data viewer to the OBD2 port and monitor coolant temperature in real time. What you will probably see is the coolant temperature can range from around 185F (or maybe a bit lower if real cold) driving down the road to possibly as high as 226F if you are in blazing hot ambient heat. With the A/C off on a warm day what you will see is the coolant temperature climb to the point the fans are turned on. For my Boxster this occurs at 212F. The fans come on the coolant temperature drops to 205F (again for my Boxster) and the fans shut off. If it is a hot day the coolant temp might climb even higher and then the fans switch to high speed. This occurs at 216F in my Boxster. On a real hot day I have observed the coolant temperature reach and maintain 226F. But it gets no higher. What the coolant gage needle does I really don't pay much attention to any more. I glance at it just from habit and looking for a big change but really it doesn't have much to offer. I do also scan the dash for any warning lights. These convey more info though of course I strive to keep the car in good condition so these never come on.

Hi Paul, I'm in the process of replacing my coolant tank too. I started tonight and less than 1 hour into the job, I reached the point where I had to take the tank out. It would not come out. Mine is a 2002 3.6 Targa. So I stopped for the night and I'll lower the engine a bit tomorrow morning to proceed with the replacement. I decided to do it myself when the local Porsche specialist quoted 200-300 Eur for the tank + 4 hours of labour. I paid 100 Eur for the tank delivered from France, and it will take me up to 3 hours to do it (first time!). Cheers, Fabrice

Fabrice- Just lower the engine. Take the two 18 mm nuts off completely and lower the engine, then on my C.1, it came out easily. Getting it back in took a few tries because I took it out the night before and stopped. And getting it in the attachment piece (the plastic block at the top of the tank to the support) took me a few tries, couldn't get it, but then lifted the front/back of it up and down, then angled it in from the front and the back and finally it just dropped all the way in. If you don't think it's not all the way in, it's not. When it does drop in, you know it. I've only been to Belgium once a few years ago.....I loved it! Started drinking beer again.....but 95% Belgium beer! Best of luck.

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Hi Fabrice, your car is MkII so your tank is much bigger and much harder to remove. Just follow the tips in post #21 or if you are desperate, you can try removing the black bracket that holds the top of the tank to the car frame. Two up-side-down screws that will be difficult to remove and reinstall but with that black bracket off, at least you can get the tank out. Just push the tank toward the front of the car as much as possible to get to those two screws.

I went out and logged my coolant temperature, and in no case did it increase above 95 degrees C. Just as I explained above, this was after running and sitting at a stop light. If I either pulled away or just increased RPM to 1500 or more, it would drop to 93 C within 15 seconds. The gauge is actually pretty accurate. Paranoia is off for now.

Thanks Paul and Ahsai for your advices. I'll lower the engine. It looks so much easier than taking out the tank bracket. Didn't manage to work on it today as I went to the Spa circuit to visit some friends driving at a track day. There were a few very nice 996s there. These 996s really grow on me! Tomorrow I'm back there again and I'll be driving my RX-8 on the track. So I'll be working on the Targa again Wednesday morning. Cheers, Fabrice

Done. In a total of 3 hours. Cost in parts : 100 Eur. Proud and happy! I love 996s!

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Great! So how did you remove the coolant tank? Engine lowered to the max and removed some other stuff?

Guys I know I've read this before somewhere but do you know what coolants are compatible with the genuine Porsche coolant? $50 for a gallon is pretty steep just for having the Porsche name on it.

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It's advisable not to mix Porsche coolant with other coolant so I would stick with the genuine coolant. Have you tried porschepartshub? There is G12 coolant that seems to be compatible but it's not much cheaper so I don't really see the point. Btw, best time to flush all the coolant if it's original. It's quite easy if yoi have an air compressor.

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Alright. I'll buy the $50 unicorn jizum sh*t. I do have an air compressor. How? How much total coolant needed? 3 gallons for a 50/50 mix to give 6 gallons?

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Yes, you need 3 gallons of genuine coolant + 3 gals of distilled water if you do a complete flush. Check out my write up here. 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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Thanks dude!

The VW/Audi G13 coolant is the same stuff as the Porsche brand and it's only $26.04 a gallon. -Jason

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Genuine coolant is $27.99/gal (+ shipping) from Porschepartshub.com http://www.porschepartshub.com/oe-porsche/00004330149 Why go aftermarket??

Porschepartshub.com Only $15 shipping to CA for 3 gallons of genuine coolant

/\ /\ /\ That's definitely cheap for genuine Porsche coolant. The VW coolant is not aftermarket, its genuine VW just not in a black Porsche bottle. -Jason

I never understand why people complain about the price of the genuine coolant 1) The coolant is cheaper ($28/gal) than an oil change even if you do a complete flush 2) You only change coolant like what, every 6yrs?

Some people want to save a buck and some just don't care. I like to save a buck here and there when I can, but I also want the best for my car at the same time. -Jason

Yea but it's not like we can get the same quality coolant at 50% of the price for going non-Porsche. In fact, you just illustrated that the VW/Audi coolant costs about the same.

I can assure you it's not the money saving aspect but a matter of principal. I'm no chemist but I have taken chemistry before. Ethylene Glycol is not a very expensive chemical. Usually there is various brands out there that buy it from a manufacturer like Dow in Germany - and yes I've visited that plant, it's a city - and then add some BS ingredient so they can patent it to make money. At the end they are the same. Of course there are some coolants that the base may be a different chemical and should not be mixed but I bet Porsche or anyone else pays like $50 for a 50 gallon drum of that stuff.

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I'm getting this.

If you sign up on the website so you can get 10% off, 3 gallons of VW antifreeze would be $70.31 and shipping is $6.39 to LA. $76.70 out the door and you should get it next day. -Jason

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I lowered the engine. So easy. And I removed the plug screwed at the end of the fuel rail. I did'nt have to remove the tank bracket. Fab

You can get coolant for you 911 at the local NAPA auto parts store. Pentofrost SF. It's the same as G12. $11.25 for a 1.5 liter bottle.