Another overheat problem
#1
Another overheat problem
Recently bought 71 Cutlass Supreme. Temp runs up to 220 on highway,drops to 200 in town driving.New waterpump,radiator flushed by a dealer using Petra flush system.New 180 thermostat.Fan seems to be operating properly.350 with a/c. Looks like original radiator. I知 not a mechanic but I may have to start training.Lots of issues with this Olds. Thanks for any help.
#3
Be sure that the radiator is clean inside & outside. You can look for cooler spots with a temperature gun. Check the ignition timing. Try to get things back to original specs and see what it does. Check the thermostat to be sure it is opening properly.
Last edited by Ozzie; September 3rd, 2020 at 09:23 AM. Reason: added information
#4
Recently bought 71 Cutlass Supreme. Temp runs up to 220 on highway,drops to 200 in town driving.New waterpump,radiator flushed by a dealer using Petra flush system.New 180 thermostat.Fan seems to be operating properly.350 with a/c. Looks like original radiator. I知 not a mechanic but I may have to start training.Lots of issues with this Olds. Thanks for any help.
#6
#7
#8
Yes, high RPM at cruise speeds can definitely lead to elevated temperatures.
My car will run at 180コ all day around town but at 70+ MPH with the AC on in 100+ summer temps the engine is turning 3400 RPM or so and the coolant climbs above 210コ. If I slow down to below 3000 RPM the coolant temp drops below 200コ. Just not enough radiator cooling capacity to dissipate the heat generated by the engine at those RPM, ambient temps, and AC operation.
My car will run at 180コ all day around town but at 70+ MPH with the AC on in 100+ summer temps the engine is turning 3400 RPM or so and the coolant climbs above 210コ. If I slow down to below 3000 RPM the coolant temp drops below 200コ. Just not enough radiator cooling capacity to dissipate the heat generated by the engine at those RPM, ambient temps, and AC operation.
#11
You could try a 180 high flow thermostat, probably will not help. It sounds like a flow issue vs air flow. As said, usually cars run hotter at low speed. The fan basically is not needed at speed and the shroud also should not be needed at speed. Make sure all the air dams are in place and maybe drain out the coolant then add a couple of things of CLR or similar, drive around for a week then flush good.
#12
The original purpose of the spring in the lower hose is for the vehicle manufacturer to be able to fill the cooling system on the assembly line using a vacuum method. Period. It is true the spring will keep the hose from collapsing. However if the hose is getting sucked closed it is because of a restricted radiator that cannot supply enough coolant to the suction side of the water pump.
Last edited by Dynoking; September 5th, 2020 at 11:53 AM.
#13
Recently bought 71 Cutlass Supreme. Temp runs up to 220 on highway,drops to 200 in town driving.New waterpump,radiator flushed by a dealer using Petra flush system.New 180 thermostat.Fan seems to be operating properly.350 with a/c. Looks like original radiator. I知 not a mechanic but I may have to start training.Lots of issues with this Olds. Thanks for any help.
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October 29th, 2011 12:30 PM