Thanks for the reply. I had a new t-stat laying around so I went ahead and replaced it. That seems to have cured it...but it's only 75F out tonight.

Before I changed it, I noticed that with the engine cold, the upper radiator hose was still full. Am I correct that it should be pretty empty when the engine is cold?

To replace it, I just opened the housing, replaced the t-stat, buttoned it up and refilled the tank. I hope that's OK.

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Mr. BILL

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