I have a 1995 Chevy Silverado 1500 Ext. Cab Z71 4x4 that I’ve had since '97. Last year it started over-heating, the temperature stays exactly where it is supposed to when I’m running down the highway, but starts to over-heat when I slow down to make a turn (up to about 230), but cools back down at an idle.
The Truck has a standard 5.7L TBI 350
Trying to remedy this problem I’ve changed the thermostat 4 times (with a 160, 180, and 195), changed the radiator, changed the map sensor (thinking that it might be leaning the fuel out to much), changed both temperature sensors, replaced the water pump 3 times (the 3rd time I ordered a Flowcooler waterpump from Summit), changed the instrument cluster and computer thinking it might be electrical, replaced the catalytic converter (thinking it might be restricted), I even replaced every hose on the motor, I then installed a brand-new GM 5.7L 350 crate engine but it did the same thing.
After installing the new engine I replaced the knock sensor, the O2 sensor, changed the throttle body (with one from another motor i had for my son’s '94), replaced the distributor, replaced the injectors, checked and made sure there wasn’t and blockage in the center intake, cut the exhaust at the catalytic converter just to make sure there was no restrictions.
I recently tried a manual temp gauge just to see if the motor was actually getting hot, which it is.
ANY help would be greatly appreciated.