Horizontally Opposed Man

Hello All!Would love some input on this :2010 Gt3 Dedicated track car all coolant fittings welded side pod mufflers removed ,The overflow tank seems to get over pressurized .Resulting in some “spritzing “of coolant Around the blue cap .The dealer felt like it would have to be either a head gasket or a cracked head.We’ve done a compression test and a hot leak down both came back completely normal if not close to perfect.On the track the car is as quick as ever and does not leak coolant.Any suggestions for further diagnosis and out right wildass guessing are much appreciated!Oh !New cap and overflow tank installed and symptoms seem to persist!

Speedster911

The " blue Caps" are known to go bad. Have you tried replacing with a new one?

Horizontally Opposed Man

Yes multiple times!

996FLT6

Don’t overtorque the brake fluid lid. You may hear a crack. Flimsy like the coolant thingie mentioned.

Fisher

Leak check/purge tools are great for troubleshooting coolant systems and preventing air pockets.

Olemiss540

If the tank and cap are good, it could have air in the lines and need bled, have you tried 45 min of driving with the flip up on the tank enabled?

It very well could be a head gasket issue only caused during HOT running conditions. An easy way to check is to see if the system holds excess pressure overnight. Since it is a closed system, if pressure is getting added from the engine, once the system is cold again it will have residual pressure felt in the hoses and when the cap is removed.

mm450exc

Did you manage to find the problem?

Elliotw44

My car has a similar "issue". But once the level got lower enough it doesn't dribble any more. My understand is this is all by design.

Horizontally Opposed Man

So wanted to give you the final word on the coolant tank overflow .It turned out that the car indeed needed a new head gasket I believe on the drivers side .We went ahead and re milled the heads and replaced the head gaskets on both sides and the car has been flawless since then.To diagnose we checked the coolant fluid for hydrocarbons and in fact they were present .Excellent repair by GMP in Charlotte NC .

Elliotw44

Great info! Thanks for sharing.Something I'll need to look into.

Robocop305

Good job finding the problem. I guess this is an engine out repair? I haven’t heard much about this issue. I wonder if your car ever got extremely hot.

RAudi Driver

Even better job coming back here and closing out the thread. An asset to all of us.

mm450exc

Thanks for the update!

I also only have this problem on track. No problem with normal driving. Will get the head gaskets checked.

Elliotw44

Following up.
Got my car coolant tested for hyrdocarbons today. Came back negative(no hydrocarbons detected). So either there is some normality to the coolant spraying and/or only on track/correct conditions to have the hydrocarbons be present in the coolant.

Horizontally Opposed Man

So you have coolant spraying out of the cap of the coolant tank but only on the track?