temp creeps up at highway speeds

[Chryco Psycho]

If you are going to an alum rad please mount it in rubber mounts , alum will not withstand the flexing for very long

 

[John h]

update:
I installed the radiator. bled the system and went for a drive. The temp was about 86 degrees and humid. as I was burping the system and adding 50/50 mix the temp of the coolant got up to 197* siting in the garage. when the system was burped and full I capped it and went for a drive. As soon as I was on the road the temps came down to 180*. I drove the same roads and exact same speeds I would drive after each flush. the car got to 186* and locked in. Even on the freeway at 75MPH and close to 4K rpm the temp never went above 188* as soon as I was back down to 65 MPH the temp went to 186* Fast forward to today. I did another test drive because it was 89 and humid. the coolant temp locked in at 186* and never moved Higher a couple of times it went lower but basically its normal temp is 186* in 2 test drives and around 100 miles driven, I'm ready to say PROBLEM SOLVED! Thanks Chris at Cold case.

Thanks everyone for all the suggestions.
John

 

[fasjac]

Nice!! Cruise on, you’re good. Glad you got her fixed.