Heater problems??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ChevyDude · 03-21-2005, 01:47 PM

Well first the 25a fuse was burned up, easy fix on the one which fixed the blower motor back to blowin'. So now after the truck is warm and you slide it to heat...it comes out hot and then within a min. is only blowing cold air??? Heater core was recently replaced and is not leaking??? I don't know??? Anyone with an idea of what could be wrong?

Alex

sneakysnake · 03-21-2005, 01:51 PM

Have you checked your water level in your radiator?

**guyryan100** · 03-21-2005, 02:06 PM

or your thermostat could be stuck open

mrein3 · 03-21-2005, 02:19 PM

Or you didn't burp the system.

You may have a slug of air in the system that needs to get "burped" out.

wyoman64 · 03-21-2005, 02:33 PM

All of the above, plus . . .does it have a circulating block heater? If so, check that it is not bypassing the heater line and causing a circulation "loop" in the cooling system.

ChevyDude · 03-21-2005, 04:06 PM

Thanks Guys...I'll check it out.

jhow66 · 03-21-2005, 04:33 PM

Heater control valve on inter fender. Check to see if it is opening. If it is not opening the hose will be cold on heater side while hot on the engine side. (hot water backing up from return line-hence hot air until water cools .

03-21-2005, 01:47 PM	#1
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	Heater problems??? Well first the 25a fuse was burned up, easy fix on the one which fixed the blower motor back to blowin'. So now after the truck is warm and you slide it to heat...it comes out hot and then within a min. is only blowing cold air??? Heater core was recently replaced and is not leaking??? I don't know??? Anyone with an idea of what could be wrong? Alex __________________ Alex 1971 Lil' Red 350 SBC 700R4

03-21-2005, 02:19 PM	#4
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	Or you didn't burp the system. You may have a slug of air in the system that needs to get "burped" out. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

03-21-2005, 02:33 PM	#5
wyoman64 Registered User Join Date: Feb 2004 Location: Northern Black Hills, SD Posts: 38	All of the above, plus . . .does it have a circulating block heater? If so, check that it is not bypassing the heater line and causing a circulation "loop" in the cooling system. __________________ 1969 Chevy K20 Fleetside 1979 Chevy K10 "ROBAHOR" (Rusted Out Beyond All Hope Of Repair)

03-21-2005, 04:06 PM	#6
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	Thanks Guys...I'll check it out. __________________ Alex 1971 Lil' Red 350 SBC 700R4

03-21-2005, 04:33 PM	#7
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Heater control valve on inter fender. Check to see if it is opening. If it is not opening the hose will be cold on heater side while hot on the engine side. (hot water backing up from return line-hence hot air until water cools . __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

03-21-2005, 01:51 PM	#2
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Have you checked your water level in your radiator?

03-21-2005, 02:06 PM	#3
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 485	or your thermostat could be stuck open



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