I recently replaced the radiator itself, because the upper radiator hose blew up on me. I tried eliminating some suspect parts, so I replaced the radiator cap with a fancy valve relief lever, a lower temp 180 DEG F thermostat, new coil wires, new sparkplugs, oil change and new coolant.
I also changed the water pump two years ago. No leaks or drips from the cooling system.
Some of the symptoms are coming back still. Like the temperature would rise above the middle of the temp gauge when I stop and idle at the traffic lights, but it goes back down to middle when I start moving. Although on the freeways, the temp gauge needle floats below the middle line and it looks all normal.
I thought I did eliminated the trapped air, so I am gonna try to fix that once again. Meanwhile, I will check the seal and seating of the thermostat as well.
Slightly off topic, but it could be another related problem: I had the engine mounts replaced (front and back) the car is shaking rough on reverse and when on idle. I didn’t do the mounts. I get an cylinder 4 misfire error code right about the same time I got these shakes. I also get these flickering instrument panel light inside the car once in a while even though I already replaced the main battery cable.
I don’t know if I missed anything, but that’s the update so far.