overheating already

[Y33TREKker]

Have you checked your coolant level in the radiator and made sure that the system is burped of any excess air pockets? Generally, the thermostat is located at about the highest level in the system of coolant passages, and if the coolant in the specific passage where the thermostat is located is a little low (meaning that it can in essence be percolating), it will read the higher coolant AND air temp and not the relatively lower temp if it were just coolant that was there.

Sometimes it's the simple stuff, and given how finicky our transmissions can be about having the proper fluid level, why should we expect that our coolant systems will be any different?

You could also always take a few manual temp readings using an infrared heat gun to see if the coolant is actually getting as hot as the temp gauge says it is.

[angeno]

Thanks for the thoughtful suggest. But actually, here's how I know it's not that. When the VX starts overheating, usually the first sign is the fact that it's power is WAY DOWN meaning that it accelerates MUCH more slowly and only then do I notice that the temp gauge is creeping up toward the H line. So it's not just merely an erroneous temperature reading. The engine is definitely running too hot (when this happens). But all I have to do to make it go back to normal is turn off the A/C and just drive at a steady rate i.e. not under load for a while. Then the problem corrects itself.

But this is not the way I want to spend the rest of my natural life, by walking on egg shells so I don't cause my VX to overheat. That's why I thought perhaps that the engine might just be old and tired and in need of either a rebuild or replacement. Not possible?

Have you checked your coolant level in the radiator and made sure that the system is burped of any excess air pockets? Generally, the thermostat is located at about the highest level in the system of coolant passages, and if the coolant in the specific passage where the thermostat is located is a little low (meaning that it can in essence be percolating), it will read the higher coolant AND air temp and not the relatively lower temp if it were just coolant that was there.

Sometimes it's the simple stuff, and given how finicky our transmissions can be about having the proper fluid level, why should we expect that our coolant systems will be any different?

You could also always take a few manual temp readings using an infrared heat gun to see if the coolant is actually getting as hot as the temp gauge says it is.