Driving home 1100 miles from where I bought this 86GT AOD Conv twice the temp gage spiked to full hot and so I immediately pulled off the road and shut it down. Everything seemed normal and I could even touch the radiator so it appeared to be an electrical glitch. I had all ready deduced not a head gasket issue the night before as radiator was still full of water when cold. Still couldn't rule out the AOD overheating yet.
Sure enough playing with all the AC controls and driving fast again up to 75mph I was finally able to reproduce the conditions that made it spike hot (noticed that the fuel gage read high too)...aha. I had flipped the fan to max and forgotten about it.
Turns out running the heater/ac fan on high is the culprit as it must draw too much current lowering the voltage and fooling those gages. Putting it back on low speed and no issues whatsoever for the remaining 400 miles home.
So there is the solution for probably alot of us driving in AC fan required areas running fans on high.
Hope this saves someone else a lot of grief or unnecessary fixing.
Sure enough playing with all the AC controls and driving fast again up to 75mph I was finally able to reproduce the conditions that made it spike hot (noticed that the fuel gage read high too)...aha. I had flipped the fan to max and forgotten about it.
Turns out running the heater/ac fan on high is the culprit as it must draw too much current lowering the voltage and fooling those gages. Putting it back on low speed and no issues whatsoever for the remaining 400 miles home.
So there is the solution for probably alot of us driving in AC fan required areas running fans on high.
Hope this saves someone else a lot of grief or unnecessary fixing.