ea82 spfi, I have been having a problem with the cooling system for some time. The main annoyance is that whenever I drive the car, as it warms up the temp gauge creeps up past normal operating temperature and stays about 3/4 of the way up but still out of the red, then eventually drops down to a quarter of the gauge like it normally runs. during the time it's reading hot, the heater is lukewarm so I figure the thermostat has not opened.
Here's what has been done:
new OE thermostat, <- maybe I didn't line up the bleed hole properly?
radiator of unknown condition taken from parts car after sticks jammed through old one and it dumped. Seems to have been working ok since I installed it. I don't know if the coolant temp sensor is working right but it seems to read the same as the other one.
new water pump and hose
I did all this work during a short period of time so I'm not exactly sure when each symptom occurred. I do remember having difficulty burping the coolant system after replacing the radiator. when it was supposed to open the thermostat and the coolant level should have dropped, instead it would start overflowing and coming out of the radiator.There is some coolant loss while driving but not very much. Exhaust isn't very telling, no white smoke.
I hear gurgling noises from dashboard and the overflow container especially when turning the car off after driving for a while.
no mixing of coolant in the oil
some crud on the radiator cap and in the tube but I'm not sure if it's a significant amount
passenger side head has a noise similar to a belt slipping, sounds like the valve train or cam. Not sure if head cracks or gasket leaks can be heard. It does seem to run rich and miss a little so I might have a valve issue?
I figure I should start by inspecting the thermostat and passenger side valves, and I suppose eventually the head if nothing else rules out the issues.
Any advice would be appreciated,