rond951

Symptoms: recently (last 2 ish wks) when returning from 30-40 min. Interstate driving 70-80 mph with occasional roll on boost 15-16 psi. When I get to my garage shut her down coolant in reservoir is sloshing between min-max marks. Never noticed this on any prior 951. Then today after a few 3-4 pulls 16 psi dialing in my E-Boost when i got home shut her down coolant tank up to the fill neck, no movement or overflow. Within 30 mins. coolant level back to normal 1/2 way between min/max. Turbo electric pump cycles fine and fans are working. Neither today or prior 2 wks tank and cap do not get super hot, I can put my hand on cap. No temp gauge issues, no coolant on dipstick or gunk bottom of filler cap. No outward signs of coolant/oil anywhere. No tailpipe smoke.

HeavyKevy68

If you look at my post a few down from yours, I am experiencing the same symptoms. Where is your temperature gauge reading when this is happening? I did a compression test (Not a leak down) and my #4 cylinder is a little lower than the rest and the threads on the spark plug are perfectly clean whereas the other plugs are dirtier. I believe mine is a head gasket issue and as a result, it's increasing pressure in the expansion tank. I ordered a test kit that tests for exhaust gases in the coolant but likely I'll be tearing it apart soon. One other issue was although I bled the system like 50x, I keep getting air in the system. Ugh......