Intermittent Coolant Leak - any ideas?

[blue62]

Originally Posted by LAP1DOUG

I have been having an intermittent coolant leak that I have not been able to figure out:

It only leaks about 1/2 quart at the right rear wheel after hard high RPM autocross runs.

I replaced the water pump with a new OEM unit thinking maybe this was the first sign of the pump bearings going, but same results after replacing. I had already changed the thermostat to a low temp unit some years ago, so I left the thermostat as is.

I replaced the coolant cap with the newer version, but no change in problem.

I pulled out rear carpet and checked tank for any leaks with engine at maximum operating temperature with the fans running, but no leak there.

It is definitely not an inter-mix issue as oil looks fine, and I'm only finding coolant on the ground after autocross runs. Driving around on the street will not cause any leakage.

Anyone else ever experience such an intermittent leak?

Thanks for any info, and Happy New Year!

My guess would be that under the conditions you describe that the coolant temp is reaching a level where pressure and expansion are forcing the coolant out the overflow. the overflow tube is above and in front of the right rear tire.