Thread: Head gasket failure or something else?

Have you replaced the thermostat after all these flushes? Could be clogged up with junk causing undue pressure. FYI the 3800 is RARELY known to blow a headgasket even if it gets overheated so I doubt that is the case. Where was the fuel smell coming from? The exhaust or somewhere else? Could be running rich if there is a vacuum leak.

Hey thanks for the reply
So this happened with the thermostat still out. Started freaking out because it didn't happen with flush 1 or 2 and I'm pretty sure I ran the car longer than I did on flush 3 when the coolant overflowed.
But someone told me that it probably happened because I had the thermostat out and the water wasn't cooling down at all, and when I turned off the engine and stopped the flow/circulation it expanded out? Seems to make sense I think right? Still confused as to why this never happened on my first 2 flushes though. I did a 4th flush and made sure to burp some air bubbles out for a good while too, and same thing happened once I shut her off, overflowing out my reservoir again. I've put the thermostat back in and plan to flush it some more to test the theory and see what happens. If it overflows again I know something is wrong.
And yea I've heard it's hard to blow a head gasket on these engines, but I tend to over worry lol.
As for the gas smell and running rich I'm not sure, I can't see any vacuum leaks and it seems to run good with no idle issues.