Hey, so recently I took the intake manifold off and replaced the leaking rear valve cover gasket, which is all gravy (no oil leaks), but in the reinstallation process I attempted to start the car a few times with 2 coolant hoses mixed up. After fixing that problem, I was burning coolant in the exhaust for maybe half an hour. Pulled the plugs and cranked her over, nothing bad in my engine. Changed oil as well, and it looked unaffected. Couple days later and my car is reaching 3/4 temp on short drives. Pressure tested today and I have no leaks, but with the rad cap off upon starting the engine a volcano burst of coolant splashes out. So a bad airlock exists within and a shop tried to eliminate most of it. To date, my car is not overheating and the coolant reservoir is correct for the first time ever. However, the mechanic said it's either a faulty thermostat (which I am replacing today) or the head gasket is starting to go. The former thankfully makes sense since my car runs perfectly and only the cooling system has been an issue.


Any insight from the experienced would be great, thanks!

 

Until the head gasket blows, it doesn't cause any problems. A head gasket is either good or it isn't, there is no "in between".

The thermostats can go bad when an engine over heats. So that is a maybe. I just hope you are not putting in a thermostat from autozone. Their thermostats just don't work well with the VQ engine.

If the gauge is still running high, maybe it's a sensor problem. Get a OBD reader and look at the engine temperature. It should be running around 200 degrees, give or take a couple.

 

if your head gasket is going, you will usually either see some smoke in the exhaust, or oil in the coolant.. if you want to test the thermostat you can place it in a pot and bring up the heat while monitoring the temp.

 

Yep, coolant burning in the exhaust but I still have good power. Pretty sure my head gasket is going, just replaced the thermostat and exhibiting the same symptoms. So not worth fixing, I have 313,xxxkm. Time for a 3.5 swap, thanks for the input guys!