Ninetynine996

After a very spirited drive today, I parked in the garage and about an hour later found a puddle of antifreeze near the rear drivers side wheel. I am assuming it's a cracked coolant tank. Any advise? Also how much should I expect to pay to replace the tank if it is the problem.

pl

that sucks, man. 996s should running around with diapers.
try to search got "coolant", and you will find lots of info.
call princeton porsche and ray cateno porsche(edison) on monday, they should give u a accurate #.
in a rough way, i think u look at a few hundread bucks. plus you need to flatbed your car to the dealer.

marlinspike

Yeah, sounds like the expansion tank to me. Don't drive it. There's a repair procedure detailed on renntech if you want to do it yourself. This seems like a good place to ask: did everybody else's also go after a spirited jaunt. I know the one in my dad's 996 did, and the bmw 540 also seems to have broken radiator/coolant lines always after spirited drives. That's not to say you can't do spirited drives and have nothing happened, but I'm just saying it seems like if coolant parts are going to go on a newish german car it's always after a spirited drive.

woody-77

Check the cap first and see if it is leaking from there if it doesn't look like you lost a lot of coolant. You will see coolant or the reminance of coolant in the top of the tank. When my cap leaked it looked like a lot of coolant but I really didn't lose too much. I replaced my cap, no problems since.

You can also try taking the cap off and tightening it back down again this sometimes works.

jlb532

Ditto to Woody's comments. Found what I thought to be a large puddle under the rear driver's wheel. (and all over the engine). Per suggestions on this board, I tried replacing the cap first-it did the trick. And I only wound up needing to top off about .5-1 quart. Not too bad.
Definitely try a new cap first.

mundman

I found a puddle under left rear of car. Expansion tank replaced under warranty. $325 incl labor car never overheated on the way to the dealer.

bet

Did the DIY 2 weeks ago. PITA but doable. Tank can be had for about $72 at Sunset.

Unless the coolant is just pouring out you can continue to drive it. Just keep an eye on the level. In general the amount of coolant lost is minimal compared to the amount of coolant in the system. You may be surprised. You drive it the next time and it will not leak (of course this doesn't mean you don't have a problem).

marlinspike

It's a pressur-ized system, you risk blowing it if it's leaking, and with the engine in the rear you might not notice, which will nicely warp your heads...don't risk driving it.

Ninetynine996

Thanks for your help guys. BTW it turns out my tank was about 1/2 quart low. Filled it back up to max. Put the cap back on and drove it for about 25 minutes. The temp guage didn't rise above 180...drove back home....no coolant leak. Not a drop. Weird. Going to Princeton Porsche in a week for an annual service so I'll let them check it out.

marlinspike

Just FYI, typically when you lose all your coolant you aren't going to see the temp rise (low coolant will though) since there is nothing for the thermocouple to measure.

pl

you may just need a new cap then.

pl

i found this the hard way on west side high way the other sunday night.

bet

Interesting on the thoughts of no indication of temperature rise when coolant is lost. On a former '00 Boxster, I damaged a radiator (didn’t know it at the time) that was leaking coolant very quickly. First the low coolant light flashed and then the temperature gauge started a quick and steady rise towards the red. I pulled into a parking lot when the temp gauge went past what I know was normal and prior to it getting into the red The same thing happened to friend on the track when one of his coolant hoses punctured.

As for it not leaking again don’t discount this too quickly. The 996/986 coolant tank leaks are typically caused by "cracks" that are small in nature. In another post, Toolpants posted a picture of the “cracks” which are difficult to see because of the discolorization of the tank. After speaking with a couple of mechanics on the issue, it seems unlikely that a catastrophic failure of the tank would take place given the nature of the “cracks” where they typically appear, and if it did the low coolant light would warn of such a problem. Typically the tanks “leak” (essentially seep) for a long period time while never producing the telltale sign of coolant on the floor. If you feel under and on the sides the tank more than likely you find “crusting” which is a sign the tank and/or the cap has a problem and needs replaced (usually the tank b/c the cap area has a drains into a rubber hose to drop out on the floor vs. spilling long the side of the tank…you can see this drain hose when looking at the tank). You may get an occasional low coolant flash but nothing consistent until the coolant level drops too low. Under certain temperature conditions this could take a quite a while. When I replaced my tank there were a few very tiny cracks in the tank on the underside in “valleys” plastic but it only allowed coolant to form a small puddle about the size of two quarters once. In fact when it did that I ordered the new tank. I continued to drive the car for 2 weeks and never saw coolant on the ground again.

bet

Wow. How long did you dirve the before you realized you lost all your coolant? Was the engine damaged? I wish Porsche would put a oil temperature gauge in the car. It could act as a safety net if this type of thing happens.

jb26jb

The tank is probably cracked. Next hot day after you shut it off and the pressure will cause the crack to expand again and you will have another leak. Tank is 165 at sunset for 99-01, taking the tank out is not that bad its the temp sensor that's tough not to crack.