did you change the thermoSTAT? if so what temp stat are you running? how big is the hill?

if you are running too high a stat, you may not have enough reserve cooling capacity available when encountering a hill.

hovering just under 100 seems too high for a normal op temp.

also your radiator may be marginal, either plugged internally or externally.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.