fbgh2o

In diagnosing my running hot condition, we discovered (my neighbour - 30+ years as auto mechanic), that the hose from the bottom of the radiator to the housing for the thermostat does not get hot - it could be grabbed with a bare hand right after the dash temperature gauge registered 100C. This does not sound right and, in my limited knowledge, implies that coolant is not flowing.

Is it likely the thermostat (which is brand new) or the water pump that is not pulling coolant?

Note while driving the car it runs at about 95C and does not overheat, so I assume that pump is still circulating coolant - which leads me to think it is the thermostat.

I posted earlier on pressure loss in the system and running hot condition, which persists despite everything suggested (repeated bleeding etc.) and thought that I had it all figured out as a defective thermostat, but now I question myself.

Darwantae951

Well unless you have a failure in the bearing or impeller (which I feel would be easily noticeable) then I'd first suspect the thermostat. You say it's brand new, huh? Where did you buy it from?

Travis - sflraver

Is the thermostat in backwards?

fbgh2o

Good point Travis, but I would have hoped that a skilled mechanic would figure that one out.

Darwin - I believe it is a Wahler thermostat, but I left the garage to source it (figures it was the only part that i did not provide).