dotframe

Noticed my coolant started dropping a bit so I added some distilled water. After only a day, it was back down another 1/2 inch. I can smell anti-freeze from the engine bay but can't see it leaking anywhere. Don't see any oil in the coolant tank.

Shop owner said he suspects it is just the coolant tank cap but will pressure test the system.

I have also had a rough idle on cold start and just praying that these two symptoms are not related!

Hoping for the best. My wallet is in no position for surprises right now.

Kahdmus

I went over a speed bump in December and cracked the rear hose. Parts were cheap, an hour labor. When I did some initial searches, it seemed somewhat common for the coolant tanks to leak..

Fingers crossed its only a minor hiccup.

Jim137

I have the same thing going on...replaced cap, then coolant reservoir but still the same leak. It is at the shop now. Good luck.

Neb

I have the same thing too, just replaced cap. Will monitor. The parts guy said the O rings on the resovoir pressure release vent can leak also.

Topaz330ci

What year and models do you guys have?

Please share the results once the problem has been found as there are 4 cases in 4 posts and it would be interesting to hear what the causes are/were.

Thanks,

Alin

fbgh2o

If it was leaking around the cap, you would probably see it around the filler neck as a pinkish white crust. Is there any evidence on the ground of a leak. I would look under the tank to see if it has cracked and is dropping down onto the exhaust manifold (which would lead to a more perceptible smell).

dotframe

Mine is an 03 with ~50k miles. The coolant tank is not too yellow and i think the cap is original.

Saw some pink crust around the top of the tank but after cleaning it off I haven't really seen more show up.

Hope to get an update today.

Rhasslinger

This is crazy, I have the exact same issue right now on my 99 C4. Definitely interested in hearing what the outcome is. thanks!

dotframe

Verdict turned out to be the coolant tank cap. When they tested it, it held 0 pressure. Pressure test on the coolant system came out clean, whew.

I don't know why but I was under the impression the 996.2 didn't have the same weak cap but I guess they did. He said that he hasn't seen an old cap like mine in a while, he thought they had all been replaced by now

I should have tried a new cap before bringing it in.

Barn996

Glad it was simple.

dotframe

Just a follow up for the archives..

The new cap has completely eliminated my leak. My old cap was blue/green in color and the new one is black. I don't know where I got the idea that this was only on the 3.4 cars but it definitly was an issue on my 03.

Sneaky Pete

Ditto.....sometimes the obvious is over looked thinking it has to be a major bill. Glad it worked out.

washington dc porsche

Did the leaky cap cause any increase in the operating temperatures?

Topaz330ci

Good outcome! I'm going to check to see if my cap is black as well...

Jim137

Mine is a '99 3.4. Started out with just smelling it, then I could hear it dripping on the header on the pipe for the middle cylinder. Things progressed and I could see it dripping to the point where it running toward the drain in my garage floor. As I mentioned before, I replaced the cap first, then the coolant reservoir and all of the hose clamps I could get to, but the problem persisted. I reached in and felt everything I could get my hands on, and everything was dry. I was worried about head gasket but dealer says no.
I just picked it up from the dealer yesterday, and they took the reservoir off and inspected it and the hoses...said it was fine (which of course is true because it is brand new). They put it back together and said it is fine now, and no more leak in the 3 times I have driven and parked it since. Still a slight smell of coolant...I hope it is fixed, will keep you all posted.