1998 chevy c1500 no heat HELP???

brentj45 · 11-30-2008, 10:26 PM

1998 chevy c1500 5.7 350 have no heat i have replaced heater core, new thermostat, new blower motor, all blend doors work great, truck dosent lose water at all, and replaced lines to heater core still no heat and water seems to circulate great all hoses get hot etc. help please!!!

gmctrucks · 11-30-2008, 10:34 PM

Welcome and howdy from TEXAS. Did you check to see if the pipes for the new heater core had plugs in them and what part of the world are you from? Maybe block the radiator with a piece of card board so that the radiator can get hot. I would have to do that to my 1957 Ford F100 it was a cool truck as well.

stumpuller454 · 11-30-2008, 10:34 PM

Could be a blend door in your HVAC unit that won`t open or close, could just be stuck sending cold air through it, or something to do with the heater controls on the dash,.....>stump

brentj45 · 11-30-2008, 10:40 PM

from north carolina, and yea i had the cardboard idea just havent tried it yet im really getting fed up with messin with it but tired of freezin my *** off as well

mudseeker · 11-30-2008, 11:02 PM

maybe try burping the system, you might have air in the lines.

gmctrucks · 12-01-2008, 12:48 AM

I hear you it's 53' over here in TEXAS and were with the heaters on and the electric blankets and some are even pushing towels under the doors well not that bad but we don't care for that cold weather.

leolkfrm · 12-01-2008, 05:56 AM

You mentioned the hoses all get hot.....are the inlet and outlet for the heater both the same temp? what is the engine temp Gage showing?
if no gage, when the truck has been driven are the radiator hose so hot you can hardly hold on to them or luke warm? When you reassembled the dash are you you sure you hooked all the plugs, I tend to agree the blend door is not functioning if everything is hot....Something to try, with the engine off operate the controls for temp from cold to hot and listen to see if the door is moving

bradrhale · 12-01-2008, 01:34 PM

just to make sure, you have checked all three blend doors?? mud might also be right in the fact that you have an air bubble trapped in the core. if you have not owned this truck since the beginning, make sure that you do not have a cutoff valve in the line. so people do not think to check the blend door when they cant get cold from the ac. so they will take a ball valve and put it inline to manually turn off the heat during the summer months. have seen that several times and once in a truck that i bought.

brentj45 · 12-03-2008, 06:10 PM

you will never guess what the problem was... after missing two days of work and replacing alot of parts, i happened to take the cover back off the heater core and it feel in the floor the clip that holds the heater core in place had came loose and the heater core was just laying there so on my way home tonight i had a kick *** heater and thanks for all your help

bradrhale · 12-03-2008, 06:11 PM

thats a new one to me. thank you for sharing.

11-30-2008, 10:26 PM	#1
brentj45 Junior Member Join Date: Nov 2008 Location: Hickory, North Carolina Posts: 5	1998 chevy c1500 no heat HELP??? 1998 chevy c1500 5.7 350 have no heat i have replaced heater core, new thermostat, new blower motor, all blend doors work great, truck dosent lose water at all, and replaced lines to heater core still no heat and water seems to circulate great all hoses get hot etc. help please!!!

11-30-2008, 10:34 PM	#3
stumpuller454 Senior Member Join Date: Dec 2007 Location: Grande Prairie, AB Posts: 2,043	Could be a blend door in your HVAC unit that won`t open or close, could just be stuck sending cold air through it, or something to do with the heater controls on the dash,.....>stump __________________ SUPERCHARGED 454 K2500 GMC! 450hp and 600ft/lbs http://www.youtube.com/watch?v=WJ27RJHfJKE "sailing with Captain Morgan often!"

11-30-2008, 11:02 PM	#5
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,376	maybe try burping the system, you might have air in the lines. __________________ i'd rather be hunting

12-01-2008, 05:56 AM	#7
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	You mentioned the hoses all get hot.....are the inlet and outlet for the heater both the same temp? what is the engine temp Gage showing? if no gage, when the truck has been driven are the radiator hose so hot you can hardly hold on to them or luke warm? When you reassembled the dash are you you sure you hooked all the plugs, I tend to agree the blend door is not functioning if everything is hot....Something to try, with the engine off operate the controls for temp from cold to hot and listen to see if the door is moving __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

12-03-2008, 06:10 PM	#9
brentj45 Junior Member Join Date: Nov 2008 Location: Hickory, North Carolina Posts: 5	you will never guess what the problem was... after missing two days of work and replacing alot of parts, i happened to take the cover back off the heater core and it feel in the floor the clip that holds the heater core in place had came loose and the heater core was just laying there so on my way home tonight i had a kick *** heater and thanks for all your help Last edited by mudseeker; 12-03-2008 at 08:25 PM. Reason: censor

11-30-2008, 10:34 PM	#2
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,037	Welcome and howdy from TEXAS. Did you check to see if the pipes for the new heater core had plugs in them and what part of the world are you from? Maybe block the radiator with a piece of card board so that the radiator can get hot. I would have to do that to my 1957 Ford F100 it was a cool truck as well.

11-30-2008, 10:40 PM	#4
brentj45 Junior Member Join Date: Nov 2008 Location: Hickory, North Carolina Posts: 5	from north carolina, and yea i had the cardboard idea just havent tried it yet im really getting fed up with messin with it but tired of freezin my *** off as well

12-01-2008, 12:48 AM	#6
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,037	I hear you it's 53' over here in TEXAS and were with the heaters on and the electric blankets and some are even pushing towels under the doors well not that bad but we don't care for that cold weather.

12-01-2008, 01:34 PM	#8
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	just to make sure, you have checked all three blend doors?? mud might also be right in the fact that you have an air bubble trapped in the core. if you have not owned this truck since the beginning, make sure that you do not have a cutoff valve in the line. so people do not think to check the blend door when they cant get cold from the ac. so they will take a ball valve and put it inline to manually turn off the heat during the summer months. have seen that several times and once in a truck that i bought.

12-03-2008, 06:11 PM	#10
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	thats a new one to me. thank you for sharing.

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