It's the expansion tank mount. Oil cooler too.

If you haven't already get a free loaner pressure test kit from the parts store so you can pinpoint your leak without the engine running.


I had a water pump leak from the weep hole that I could not find, with the test kit it was obvious. Either the leak was slower when the engine was hot or it was evaporating before it was obvious where it was coming from.

Yes I got an pressure tester, but when I removed the air intake it looked obviously that the hose with the temperaturesenor was leaking