At the track yesterday, after finishing a session and pitting in, my coolant buzzer went off. I immediately shut it down. I topped the coolant off, but it took no more than 4oz so I thought maybe a small leak or something and I would keep an eye on it. After the next session, the buzzer came back again upon parking the car and letting it idle. This time it was down closer to 16oz. I called it quits for the day after that and drove it home. When I got home, I checked again and it was down 4oz again.

No symptoms: car is running fine, making great power. No white smoke, no sweet smelling exhaust. No leaks anywhere I can find, no spots on the garage floor. Champagne test - when I first start the car, there are indeed some tiny bubbles rising to the surface.

I looked at someone else's test video they posted here (http://s22.photobucket.com/albums/b3...=VID_00007.flv) but mine's nothing like that. Just one itty bitty bubble at a time coming up, not even disturbing the surface. Like 100x less than the one in this video FWIW.


I should point out that the car has all the reliability mods, and at no point did the water temps ever get above 190 the entire weekend on the track. I've never overheated the car before, and this motor has ~10k miles on it (PFS-installed reman). I run dual oil coolers and only 9 psi on stock turbos.

Is this the beginning of the end, and if so... What happened?

 

Have you opened up the coolant system lately ? Make sure all air is out. PErform a compression test next.

Later

 

I would suggest checking your coolant caps and doing a pressure test on the cooling system. Make sure to squeeze the radiator hoses as you top off the coolant. It will help push out any air.

 

The end all test is to do the following:

1. Fire up the car and get it to go through a few heat cycles
2. Shut the car down and let it sit overnight
3. Remove a spark plug from each chamber
4. Turn the motor over by hand

If coolant leaks from your spark plug holes, then you have a somewhat major o-ring leak.

 

+1

Autozone rents out the pressure testers free.

 

Opening the coolant cap when the car is hot after a track session should SPEW a ton of coolant because its under pressure. If you were able to add coolant, that means something is wrong. Mahjik's suggestions were good. WaLieN's test would be worst case scenario (coolant seal failure = rebuild).

thewird

 

After the cooldown lap the water temps are hovering right at about 160. When I pit in and shut down, I cover the cap with a rag and relieve the pressure very slowly so as not to boil water in my face.

I will see about renting or buying a pressure tester today and start there. Thanks!

 

Is the level in your overflow...overflowing?

 

Level appears to be normal. It's certainly not pulling coolant out of the reservoir when the system runs low though, so it's not generating vacuum. I've got a pressure tester reserved for tonight so we shall see!

 

Good news! Got the pressure tester hooked up tonight and pretty quickly found my problem. When I pumped the system up to around 15 psi, the AST cap immediately began to bleed off pressure to the overflow tank which I heard gurgling. Shortly it settled down to 10 psi and I started hearing a drip drip smacking the cardboard under the car. Sure enough, coolant was coming out near the driver side firewall.

Looks like one of the hoses for the heater core where it passes under the oil filter housing. No coolant was leaking out of here with the car running or parked before, but with enough pressure it was immediately obvious. I'll have to tear a bit into the car to get to it, but I suspect it's probably just due to the factory spring clamp. I'll double up with a real hose clamp and see if that stops it first.

Thanks for the help everyone! I'm glad to have found something concrete and I feel more confident that my motor is okay after all.

 

Lol, I had the same problem with the heater core. I bypassed it and haven't bothered to fix it yet although I probably should cause its getting cold at night.

thewird

 

Having just taken care of a failed coolant seal last winter, I wasn't exactly optimistic. Nice to hear good news for a change.

 

Just a quick update. I've replaced the heater core hose along the firewall. I found the reason it was leaking -- the oil pressure sender attached to my RE Speed oil filter pedestal was rubbing against the hose. It's a pretty cramped fit down there, so I ordered an extension to relocate the sender away from the pedestal and out of harm's way:

http://www.tunerschoice.com/xq/aspx/...qx/product.htm

Also took this opportunity to flush the coolant and perform an AST delete. Everything seems to be working fine now and the cooling system pressure tests and holds 15 psi with no leaks now.

Thanks everyone for your help!

 

Nice find.. A pressure tester is a great tool for finding the leaks. I like when a motor story has a good ending. ( or continuation) G

 

I'm glad it turned out to be something relatively minor!