When I went back to my original thermostat, the overall engine temps did drop, I still was still unable to use the ac going up Bass Lake grade on highway 50. If ac on then engine temp would hit 110C, with it off, about 95-100C.

Today I modified my spare thermostat by cutting the springs out, heating it until it was opened 1/2 inch, then soldering the main brass shaft and the diverter in place. It fixes it open all the time and retains the diverter.

It was cool today at 80F, I drove up Bass Lake grade with ac on at 65-70mph and the temp hit 95C max. I am a happy camper. I know that I'll have to change back the original thermostat in November, but its a small price for the engine temp reduction.

Before, when I re-installed the old thermostat, and today when I installed the modified thermostat, I had to drain coolant. When I poured the coolant back in, I poured it into the upper radiator hose untill it started to dribble out of the radiator top hose nipple, the rest of the coolant was poured into the tank. This method seems to get more air out of the head. Later I parked the car on a hill to add coolant to the hose and found I could not add any, usually I could add coolant a couple of times before it was full. This may have been what dropped my engine temps when I re-installed the original thermostat, unable to say for sure.

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