1994 Caprice heating problems

[mdjohnston]

My Caprice doesn't heat properly. I have replaced the heater core, hoses, and thermostat. Actually have a 195 degree themostat installed. System has been flushed. I have messed with it and am wits end. At higher rpm I get more heat. At peak of heat I get around 90 degrees according to thermometer. Maybe because it is so cold out this doesn't seem like enough. Does any one know what theirs puts out? And what other problems may cause this. I have covered all the bases that I am able to. thanks.

[4evrbad]

My 94 does not put out great heat either I have a 160 stat in. Before with the stock stat the heat worked much better. The caprice does have an excellent cooling system with reverse flow. If you have a block heater which many police package 9c1 do use it, the engine will heat up quicker. Also if you are sitting in traffic or drive in stop and go conditions your caprice will run hotter, If you drive alot on the highway it tends to run a bit cooler.

[463]

there is 1 more base to cover in temp problems. thats the over looked rad cap. the quickest way to check it is to get a new one and try it. if you have a rad cap/psi test pump this can be used to prove the cap as well. this tester is also used to test the cooling system for leaks by pressureing the cooling system mty or full of coolant (when its cooled off. not hot) as the pressure gauge is increased to the psi for the car cooling system stop and let it sit for ten min to see if a loss of pressure is showing on the gauge if its had a pressure loss its time to look for leaks eg: hose clamps, rad, heater core,eng block ect. then retest. with my sons 91 caprice classic 305 cid we did a heater core replacement and the in/out pipes were not the same as factory that was removed (it was so close) so we took both to the rad shop and had the pipe end of the heater core switched to get it to fit like it should. it now heats good with the aid of a storm front placed on the grill. with my wifes olds silhouette i sent it in to the gm dealer for a flush of the injectors they told me when it was on the computer that it was running cool and recommend was to replace the thermostat. so a $110.00 for that i went on my road test and the heat gauge came right up to its normal spot. as i got back to stop and go driveing down came the temp as well as the temp gauge. so i came home pulled out my rad/system psi tester and did a cap and cooling system test (after it was cooled down) system was good and cap was week (12-14 psi) new cap 15-17 psi so on went the new cap and a road test with the way it should work no loss of heat. so it was a quick $110.00 dollar education in shops and incorrect analysis. so for a test on the removed thermostat i did the test and the thermostat fuctioned at 195 Of as it should. i have found over the years that when its -20 to 40 0f tha the coolant will leak out around hose ends thermostat houseings, heat core connections and this is seen when looking over the eng bay with a cold eng you may see coolant present. it may require a snug up of a clamp. hope this helps 463

[mdjohnston]

Originally Posted by 463

there is 1 more base to cover in temp problems. thats the over looked rad cap. the quickest way to check it is to get a new one and try it. if you have a rad cap/psi test pump this can be used to prove the cap as well. this tester is also used to test the cooling system for leaks by pressureing the cooling system mty or full of coolant (when its cooled off. not hot) as the pressure gauge is increased to the psi for the car cooling system stop and let it sit for ten min to see if a loss of pressure is showing on the gauge if its had a pressure loss its time to look for leaks eg: hose clamps, rad, heater core,eng block ect. then retest. with my sons 91 caprice classic 305 cid we did a heater core replacement and the in/out pipes were not the same as factory that was removed (it was so close) so we took both to the rad shop and had the pipe end of the heater core switched to get it to fit like it should. it now heats good with the aid of a storm front placed on the grill. with my wifes olds silhouette i sent it in to the gm dealer for a flush of the injectors they told me when it was on the computer that it was running cool and recommend was to replace the thermostat. so a $110.00 for that i went on my road test and the heat gauge came right up to its normal spot. as i got back to stop and go driveing down came the temp as well as the temp gauge. so i came home pulled out my rad/system psi tester and did a cap and cooling system test (after it was cooled down) system was good and cap was week (12-14 psi) new cap 15-17 psi so on went the new cap and a road test with the way it should work no loss of heat. so it was a quick $110.00 dollar education in shops and incorrect analysis. so for a test on the removed thermostat i did the test and the thermostat fuctioned at 195 Of as it should. i have found over the years that when its -20 to 40 0f tha the coolant will leak out around hose ends thermostat houseings, heat core connections and this is seen when looking over the eng bay with a cold eng you may see coolant present. it may require a snug up of a clamp. hope this helps 463

Thanks, I forgot to mention I replaced the radiator cap too. But they are cheap so my be time to try another. I appreciate the info.

[mdjohnston]

thanks for the info.