Coolant reservoir - from where does it normally leak?

What part of the reservoir does it normally leak? Mine is the original with part ending in .01. The reason I ask is that the coolant level resides at the "low" mark. However I have filled it to the "full" level with distilled water 3 times over the past several weeks and it keeps going back to the "low" level. But I never see any conspicuous indication of a leak. Is it possible the leak is from above the "low" level? It's going in Monday for an oil leak (CPO) likely the variocam which is no big deal, but I wanted to have a case for the dealer to replace the coolant reservoir under warranty. Thanks.

Mine did the same thing for months than really leaked bad. Mine even passed a pressure test at Porsche, they burped it using the vent, its right behind the cap, lift it up its spring loaded and drive around for an hour, it should get all the air out, if thats what is wrong. The answer to your question is the bottom of the tank cracks, it cooks from heat from the muffler. If you are leaking, you'll see stains under the exhaust tip.

Okay, this response is sort of sideways to your question, and done without a complete and total search of all posts on this topic, but... I don't believe you should be using distilled or any other type of water in the coolant resevoir. I believe the coolant fluid is unique to Porsche. As I recall in my memory banks, adding water will actually cause corrosion problems internally in the cooling system. I could be wrong. Hopefully Macster will see this thread and correct me and also give you the straight scoop on why the level is not holding. However, you are, in my opinion, absolutely correct about changing out the reservoir preemtively - if the reservoir plastic is orange-ish, then it is old and could crack. Should be pretty much clear/white plastic.

Two of the more common leaks are a split in the bottom and the cap, I think the cap is up to rev 4. If you have 01 you might want to update. At first it tends to leak when parked for awhile after a good ride. The engine heat soaks and the pressure buildup tends to push water out. If you can get a mirror under there you might be able to see stains on the inner quarter panel/bottom of the reservoir.

Mine leaked from the level sensor which is on the bottom. The fluid level never went below the low line on the reservoir though, so it might well be leaking from the same place. In addition to looking, you can also feel the underside of the for built up crud (wear a nitrile glove pls)

Mine leaked a very small amount for almost 4 years until I finally decided it was time to replace it. The original white tank turns yellowish from engine heat and time. Not the easiest thing to do on your Porsche, but worth it knowing that no more antifreeze is leaking somewhere in your engine compartment.

"While you're in there...", you should carefully examine the level sensor for cracks. Mine had some, so I replaced it. relinuca

They don't *normally* leak But when they do...reservoir cap seems most common cause, and is easiest to fix. After that (from what I've digested from similar topics on this and other boards) it's the result of aging plastic cracking at stress points--any connection to the reservoir. Having said all that...if what you're seeing is that the coolant level returns to the "low" mark and then stays there, dropping no further...then the leak is probably located at a height in the reservoir where the coolant runs when the engine and coolant are at full operating temperature, when the cold level is at the "low" mark. Or else the reservoir is bulemic and doesn't like being fuller than "low". Good luck.

Definitely leaking. It's on the exhaust tip and located a few drops on the pipe when I had the rear passenger side jacked up. CPO should cover it if it's the tank. They won't drop the tranny for this, right?

I think one must lower the engine a little bit in order to slide the reservoir out--can be done by supporting the engine with a jack, loosening the motor mounts and then jacking the engine down just enough for the reservoir to clear. Should not have to remove the engine or transmission. At least that's what I've read...I've lucked out so far and haven't needed to replace mine. Good luck.