Overheating 350 w/ AC on?
Question:
Thanks guys.This usually happens after I have been driving for about 20-30 minutes on the highway.When the engine temp gets to normal,it then goes up to 180,fine,then it will go back down to 160,fine,then to 180 and then to 210.I went ahead and got a 160 thermostat and put it in and I’ll let you know how it goes.
Response:
My 90 Gmc ,350 ,auto,600 edelbrock carb.The timing is right.It has a new water pump,180 thermostat,radiaitor is full and clean of corrosion.The truck never gets over 160 anytime,any weather,any temperature until the air is cut on.It starts to get warm and hovers around 180 and then starts going higher and higher and got up to 210 yesterday and I cut the truck off.I would like to know why it’s doing this?Thanks
Response:
You may need to split the rad and A/C condensor, and using a nozzle on your garden hose (careful not to damage the fins), blow out the stuff collecting in your rad and condensor. Maybe bad thermostat?
– Hide quoted text — Show quoted text -> My 90 Gmc ,350 ,auto,600 edelbrock carb.The timing is right.It has a new > water pump,180 thermostat,radiaitor is full and clean of corrosion.The > truck never gets over 160 anytime,any weather,any temperature until the > air is cut on.It starts to get warm and hovers around 180 and then > starts going higher and higher and got up to 210 yesterday and I cut the > truck off.I would like to know why it’s doing this?Thanks
Response:
That is not too high a temp for hot weather with a/c on. Usually those engines ran 195 thermostats. Your thermostat may be stuck partially open allowing it to run cool, and overheat with a/c on. Roy – Hide quoted text — Show quoted text – > You may need to split the rad and A/C condensor, and using a nozzle on your > garden hose (careful not to damage the fins), blow out the stuff collecting > in your rad and condensor. Maybe bad thermostat? > My 90 Gmc ,350 ,auto,600 edelbrock carb.The timing is right.It has a new > water pump,180 thermostat,radiaitor is full and clean of corrosion.The > truck never gets over 160 anytime,any weather,any temperature until the > air is cut on.It starts to get warm and hovers around 180 and then > starts going higher and higher and got up to 210 yesterday and I cut the > truck off.I would like to know why it’s doing this?Thanks
Response:
Chris, Turning on the AC put an additional load on your engine. You didn’t describe the type of driving state you are in when the engine begins to warm up after AC is on. If you are idling or in stop and go in heavy traffic, it is normal for the engine to warm up due to the additional load on the car, minus good air flow into the engine compartment (through the radiator). According to the information I have gleaned regarding GM engines (across the board), 210 is considered their "normal" temperature. If I remember correctly, this is about halfway up the temp gauge, and therefore, far from an overheat temp. If you were getting to 260 or 270, then I would start to worry about overheating. I have had several GM cars (including a ‘91 Chevy Silverado 350) and I seem to recall all of them getting to 210 in traffic with the AC on in summer. I further seem to recall the radiator fan kicking in at about 210 without the AC on. If you don’t notice the fan coming on at 210 with the AC off (check for slight change in engine idle, or sometimes you can even hear it), or it doesn’t come on full time when you switch on the AC, then you might have a small problem. If the engine stays around 210, I would say you have a completely normal GM engine temperature. Another thing to consider is your engine coolant, just since we are on the topic. If it is not properly diluted (I use 30-70 water to coolant) then you could get a bad (inaccurate) reading on the temp gauge, regardless of season. Hope this helps, HB4 > My 90 Gmc ,350 ,auto,600 edelbrock carb.The timing is right.It has a new > water pump,180 thermostat,radiaitor is full and clean of corrosion.The > truck never gets over 160 anytime,any weather,any temperature until the > air is cut on.It starts to get warm and hovers around 180 and then > starts going higher and higher and got up to 210 yesterday and I cut the > truck off.I would like to know why it’s doing this?Thanks
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