Hey everyone,
I developed a coolant leak a week or so ago. After a drive home, I went out to the garage to find a puddle of coolant on the driver's side, more or less even with the trailing edge of the rear tire. I had my expansion tank replaced 2.5 years ago when I first bought the car, so I didn't immediately think that was it, but when I dug around, I did find a hairline crack on the inside of the tank (facing into the engine bay). It didn't seem to be leaking from that spot, but I epoxied over it anyway in the hopes that if it was it, I'd buy myself some time. Drove around the block, still leaked. Given where the leak continued be hitting the ground, I thought maybe the non-visible outside side of the tank may have been cracked as well, so I ordered a replacement and replaced it this weekend.

Old tank didn't have any obvious cracks other than the one I had already seen. New tank went in, I flushed all coolant while I was at it, and proactively replaced the water pump since the system was empty anyway and I couldn't find a record of it being done by previous owner.

So, after all of the above, it still leaks! Seems to be hitting the ground in the same place, and now I know for sure it isn't the expansion tank. I didn't seen any obvious cracked hoses or loose clamps while I was in there. Only leaks while running, but engine isn't even up to full temp, so doesn't seem to need a lot of pressure to leak.

Any ideas what else it could be? I'm taking it to my Indy in the morning, but I feel kind of defeated. I'm glad I got some proactive stuff done, but ultimately, that was a lot of work for little net effect.

Thanks in advance for any thoughts or ideas on what I may have missed.

-Don

 

Take a cup of water and pour it ON the tank. There's a hose which will catch any overflow. Watch where that water goes....if its the same spot as the coolant, I would suspect the coolant cap is gone. This is how I figured out mine wasn't sealing properly. New cap, no more leaks.

 

Ditto. I had same experience as AWDGuy. And get the latest (.4?) cap.

 

Thanks guys. Newer cap, less than 2.5 years old. I did double-check after your suggestion just to be sure, but doesn't look like it's coming from there. Top of tank is bone dry.

 

Since you replaced the coolant tank and have a new cap, water pump, it has to be one of the hoses, and there are quite a few of those. See here - http://www.autoatlanta.com/porsche-p...section=105-05
Maybe with the help of a shop, you can pressurize the system and locate the leak. It really should be evident once the system is pressurized since it is leaking enough to puddle on the ground. Good luck!

 

Thanks Joe. Agreed it's likely a hose (fingers crossed), though guessing labor to replace a few of those is going to hurt depending on where they run to. Oh well, I keep telling myself I got some proactive stuff out of the way and it was somehow worth it.

I'll respond to the thread once I hear back from my Indy. He's got the car already this morning.

 

Well, shop got back to me and it appears to be coming from the AOS. I guess I read in another thread that there was a coolant attachment on the AOS, just didn't register that it was going to be the culprit. I'm letting Indy do the work as I didn't have much fun with the water pump replacement this weekend, and that is supposed to be the easier of the two projects to do. My big ol' hands were likely not going to be able to reach everywhere needed to replace the AOS myself.

Good to know what it is though, and that it wasn't anything 'too' major. Can't wait to get it back. I love driving that car.

 

Thankfully it was the AOS leaking externally, not internally. And yes, there are two coolant lines running to the AOS. From your original description of where it appeared to be leaking, I considered the AOS but thought it was to far in to be the culprit. Anyway, good thing to have found and replaced. I have replaced my AOS and it is a PITA job. Given the 3 day job and numerous wounds I sustained, I think I would gladly pay someone to do it again.