Engine gets hot at idle

[Blessed66]

Originally Posted by burkeftm

Another thing to check is ,does your truck have a heat riser (spring or vac operated flap) between the r side exhaust manifold and the exhaust pipe. I had one with the same symptoms as you described ,driving temp would be ok ,idle at traffic light mine would go above 230 if I let it idle long enough it would boil over. The flap was seized in the closed position, Bob

Oh, that's a good one! I didn't think of this. Half the reason why I'm using headers in my other thread (not trying to threadjack or promote). It can mimic the same symptom as a plugging converter you had mentioned (Dannyboy) which includes overheating due to trapped exhaust gasses.