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Old Oct 14, 2018 | 03:01 PM
  #1  
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Default Leaking coolent

Hey guys. I did a track day a couple months ago and I noticed I was leaking coolant after the second session was completed. I was able to get home with no problems. I was busy with other aspects of life and just recently fired the car back up after topping off the reservoir with coolant.

For the first few minutes after starting the car it smelled like gasoline. Keep in mind it hadn't been started for a couple months so was probably running lean. It was also running rough. I jumped on the freeway and the light where the temperature gauge is went on so I immediately turned around and when I parked in the garage I saw all this coolant dripping out under the driver side tail pipe.

I snapped a photo of where the coolant is leaking from but it's hard for me to tell because there's a metal plate there so I don't know where it's actually coming from. I'm guessing the reservoir is cracked even though I just put a new one in two years ago.

Any advice as what I should look into would be appreciated. What made me more nervous than the coolant all leaking out was that the car was running rough.

Thank you for your insights 😊

Coolant tank is above that plate

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Old Oct 14, 2018 | 04:54 PM
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Like other recent posters of cars with coolant leaks, you’re going to have to get under the car and find the leak. You can also take the snorkel off and have a look from the engine bay up top.

If your coolant light was blinking or solid on, that is an actual diagnosable method to find the problem. Exactly how low were you on coolant both times you said you were low?
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Old Oct 14, 2018 | 04:59 PM
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One of the best tools to get is a coolant system pressure tester. $100 well spent. It will allow you to test the system, find the leak without the engine running (and getting burnt with the hot exhaust). Get one of those and you will find the leak in no time.
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Old Oct 14, 2018 | 05:59 PM
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Sounds like another case of a coolant tank giving up the ghost. I'm just speculating so don't start buying parts just yet. What year is your car and do you know if it's the original tank? Can you easily see the fluid level through the plastic or is it very opaque and yellow? A leak from the cap or tank can drip down to the driver side coils and cause the rough running that you're experiencing. It seems like this is an epidemic lately but that's due to the age of our cars and the fact that this is a plastic tank that is subject to pressure and many heat cycles.

A blinking dash light indicates that the fluid level is low. A solid light indicates overheating.
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Old Oct 14, 2018 | 08:14 PM
  #5  
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Thanks for the reply's guys.

It's a 99 c2. I purchased it with 25k miles on it a few years ago and replaced the tank and the cap 2 years ago because of a leak. It's definitely coming from an area beneath the tank, I just can't spot it from under the car.

I'll buy the system pressure tool, thanks.

The temp gauge was blinking, indicating a low level of coolant. The car has never over heated in my possession.

I'm hoping the new tank cracked because maybe I had too much coolant in there when I went to track it and the pressure caused a problem. I rarely hear the auxiliary fans on the vehicle, but they were definitely running that day. Started out as a little dribble. I have since put 20k miles on it in my 3 years of ownership and the tank was aftermarket. My concern when I have these problems is that it's d chunk, intermixing, bore scoring or 'insert expensive problem to fix'.
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Old Oct 14, 2018 | 09:30 PM
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Originally Posted by OverTake
Thanks for the reply's guys.

It's a 99 c2. I purchased it with 25k miles on it a few years ago and replaced the tank and the cap 2 years ago because of a leak. It's definitely coming from an area beneath the tank, I just can't spot it from under the car.

I'll buy the system pressure tool, thanks.

The temp gauge was blinking, indicating a low level of coolant. The car has never over heated in my possession.

I'm hoping the new tank cracked because maybe I had too much coolant in there when I went to track it and the pressure caused a problem. I rarely hear the auxiliary fans on the vehicle, but they were definitely running that day. Started out as a little dribble. I have since put 20k miles on it in my 3 years of ownership and the tank was aftermarket. My concern when I have these problems is that it's d chunk, intermixing, bore scoring or 'insert expensive problem to fix'.
As long as the coolant is on the outside of the engine, the fix won’t be that expensive

Four functions of the coolant warning light:
1. Engine coolant level too low -- light flashes slowly (0.5 Hz)
2. Engine compartment temperature too high -- light flashes slowly (0.5 Hz) (engine compartment blower might be faulty)
3. Engine coolant temperature too high -- light is lit; pointer on the right
4. Temperature sensor at water outlet faulty -- light flashes rapidly (1 Hz) ; pointer on the right
Note: The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously."
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Old Oct 15, 2018 | 08:32 AM
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Do yourself a favor and get an OE expansion tank. I have heard over and over that the aftermarket tanks are worthless, as you have now discovered.
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Old Oct 15, 2018 | 12:59 PM
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Passing on something I just learned in another thread - Porsche Coolant Tanks for MK-I (like mine) are crazy expensive $500+. Porsche tanks for MK-II are around $120. I don't know why there is such a disparity. I bought a Made in Germany OEM tank for about $200. Make sure you have the latest coolant cap with part number ending in "04".
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Old Oct 15, 2018 | 01:04 PM
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I think this year in the 996 world is going down as the "The Year of Expansion".
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Old Oct 15, 2018 | 01:26 PM
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Yes. Last year it was water pumps.
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Old Oct 15, 2018 | 06:15 PM
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Last msg didn't post.

So, do you guys think my rough idle is un related to the coolant issue? It felt just like it did on my daily driver when I needed to replace a coil pack. Like it was operating on one less cylinder.

Also, I already own a airlift that I never used when I replaced the expansion tank the first go around. Anyone of you know if this adapter will work with it?

Assenmacher Specialty Tools FZ 22 Radiator Adapter for Volkswagen and Audi


Want to express my gratitude again for the responses! I'm not rich, and didn't think I'd own a 911 at this point in my life. Have absolutely loved every minute of driving it, but man it sucks to think the engine might be toast whenever I encounter a problem!
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Old Oct 15, 2018 | 06:23 PM
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Originally Posted by OverTake
Last msg didn't post.

So, do you guys think my rough idle is un related to the coolant issue? It felt just like it did on my daily driver when I needed to replace a coil pack. Like it was operating on one less cylinder.

Also, I already own a airlift that I never used when I replaced the expansion tank the first go around. Anyone of you know if this adapter will work with it?Assenmacher Specialty Tools FZ 22 Radiator Adapter for Volkswagen and Audi


Want to express my gratitude again for the responses! I'm not rich, and didn't think I'd own a 911 at this point in my life. Have absolutely loved every minute of driving it, but man it sucks to think the engine might be toast whenever I encounter a problem!
Yes that adaptor fits 996 48x3mm https://www.google.com/aclk?sa=l&ai=DChcSEwj2y6f3r4neAhWJjcgKHcFeBbUYABABGgJxdQ&sig=AOD64_0lpRd MbbwGV5A0AsRsN8zsAQEMuA&ctype=5&q=&ved=0ahUKEwjd-KD3r4neAhVwTd8KHVDsDC8Q9aACCDM&adurl=
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Old Oct 15, 2018 | 06:31 PM
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Coolant leaking on coil packs and boots with cracks can deffinately cause a rough idle.
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Old Oct 16, 2018 | 02:37 AM
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Originally Posted by De Jeeper
Coolant leaking on coil packs and boots with cracks can deffinately cause a rough idle.
Even without damaged or cracked coils. A day after replacing my coolant tank I had a rough idle and got a misfire code on cylinder 1. I replaced the coils and plugs even though they weren't due for changing. There was nothing wrong with the old ones - no cracks and they measured the same resistance as the new ones. The plugs looked good too. I noticed that coil #1 was a little bit wet on the shaft. Not very much, just a slight bit of moisture. There was quite a bit of coolant left in the lines when I disconnected the tank. I also disconnected the fuel lines and a fair amount of gas spilled as well. I guess some of that fluid worked its way down. I probably could have just wiped off the coil pack and reused it but I installed the new ones anyway. Cylinder 1 is directly under the coolant tank.

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Old Oct 16, 2018 | 09:01 PM
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Bill, thanks for sharing that. That's a big relief to know that the coolant leaking from the tank could be causing the misfire. An obscene amount dripped out in that area, so hopefully that's the cause.
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