Heating Problem

02S10X · 10-12-2006, 05:52 AM

Bought an 02 xtreme 4.3L. It had heat when I got it and now the heat is getting colder. Coolant level is ok and I changed the thermostat. Defrost mostly is blowing cooler than other vents, when the control panel is turned off it seems to blow hotter down at the foot vent. My question is could this be a clogged heater core or the hot cold switch on the control panel?

bradrhale · 10-12-2006, 10:50 AM

could be several things. i dont think that you would have a clogged core but anything is possible. you do have a valve that opens and closes the hot water entering the heater core that is malfunctioning. i have had that problem before. you might also have a problem with the control panel like a fuse or something actually in the panel.

bobcat5544 · 10-12-2006, 01:17 PM

With the truck running and heater/ac on will air blow out of the vent you select (defrost, dash vents, floor). With the controler on cold select vents. move the knob from cold to heat does any heat come out, when doing this listen on the passanger side under the dash do you hear a constant vacuum sound.

02S10X · 10-13-2006, 05:51 AM

I talked to a guy at a GM dealer yesterday, he told me they have seen this problem before. He said to back flush the heater core, the dexcool antifreeze for some reason gets gummed up in the heater core. Of all the trucks they have done this on he said it has worked. I will try it this weekend and let you know.

10-12-2006, 05:52 AM	#1
02S10X Junior Member Join Date: Oct 2006 Location: Akron,OH Posts: 2	Heating Problem Bought an 02 xtreme 4.3L. It had heat when I got it and now the heat is getting colder. Coolant level is ok and I changed the thermostat. Defrost mostly is blowing cooler than other vents, when the control panel is turned off it seems to blow hotter down at the foot vent. My question is could this be a clogged heater core or the hot cold switch on the control panel?

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10-12-2006, 10:50 AM	#2
bradrhale Moderator Join Date: Apr 2006 Location: Texas Posts: 3,605	could be several things. i dont think that you would have a clogged core but anything is possible. you do have a valve that opens and closes the hot water entering the heater core that is malfunctioning. i have had that problem before. you might also have a problem with the control panel like a fuse or something actually in the panel.

10-12-2006, 01:17 PM	#3
bobcat5544 Full Member Join Date: Sep 2006 Location: St. Louis, MO Posts: 27	With the truck running and heater/ac on will air blow out of the vent you select (defrost, dash vents, floor). With the controler on cold select vents. move the knob from cold to heat does any heat come out, when doing this listen on the passanger side under the dash do you hear a constant vacuum sound.

10-13-2006, 05:51 AM	#4
02S10X Junior Member Join Date: Oct 2006 Location: Akron,OH Posts: 2	I talked to a guy at a GM dealer yesterday, he told me they have seen this problem before. He said to back flush the heater core, the dexcool antifreeze for some reason gets gummed up in the heater core. Of all the trucks they have done this on he said it has worked. I will try it this weekend and let you know.