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

Suicide-D · 12-10-2003, 01:24 PM

I have a weird situation going on. My heater blows cold air all the time. I have felt both heater hoses after the truck has gotten to operating temperature and they are hot but the heater air is barely warmer than outside air.

I have noticed leaves and pine needles blowing out of the heater duct. Is it possible for the leaves to have the heater core blocked and the air is moving around the core without getting heated? It feels like it blows fairly hard, just not warm.I am about to pull off the heater box but that is such a pain in the arse.

I doubt I will need a heater much, but when you need it, you need it.

Thanks,
Darryl

**CPNE** · 12-10-2003, 01:30 PM

Is it non ac? If so, remove the plastic cover that the "hot - cold" cable runs too and check to make sure the flap to divert the outside air thru the heater core is actually working. This is under the dash on the passenger side. The cable has a clamp that will allow your to adjust it.

I know these things because it was 10 below zero here this morning.

68 Suburban · 12-10-2003, 01:34 PM

Heaters? What are they used for?

:p

Suicide-D · 12-10-2003, 01:36 PM

it is non-ac... Thanks, I 'll check that

10 below... ouch I couldn't do it.

Suicide-D · 12-10-2003, 01:53 PM

Well I think the core must be blocked. I can feel the door move that CPNE said to check. But when it is in the heat position it blows a lot less than when it is in the other position.
I didn’t start the truck so I don’t know if the temperature would change depending on the position.

I guess I know what I get to do after work tonight. Oh Boy!!

I mainly use it for a defroster. I drive less than fifteen miles to work and it rarely gets lower than the low 30’s here

The pisser is I did it last year on my 68… ended up selling that truck in the spring…

mrein3 · 12-10-2003, 03:37 PM

Burp your coolant system. The stock configuration of the coolant system has excess coolant vented to the ground. After a hot summer you might have lost a bit of coolant so now you have an air bubble.

krue · 12-10-2003, 04:43 PM

I just removed and cleaned out my blower box and vents. Man I got about 10 lbs. of crap out of there! There was so much crap in there! You will be amazed by how much junk accumulates in there.

pierce · 12-10-2003, 06:19 PM

Your thermostat might be stuck in the open position.

Suicide-D · 12-10-2003, 10:08 PM

not as much as i expected...it still doesn't blow as warm as thought but it was a big difference... i'll check the thermostat later...thanks guys

dinnut · 12-10-2003, 10:47 PM

thats quite abit of crap

**Classic Heartbeat** · 12-10-2003, 11:00 PM

You should also check to see if you are getting coolent flow through the heater core. If not that would be your problem and you would need to replace the heater core. WES www.ClassicHeartbeat.com

cableguy0 · 12-11-2003, 12:35 AM

back flush the heater core you will probably get a lot of black nasty looking crap out of it. when i replaced mine the old one was 2 or 3 pounds heavier than the new one because of all the crud that was inside of it

Suicide-D · 12-11-2003, 11:09 AM

I did back flush the core, several times until the water was clear. I don't think it's getting all that warm. I'll pull the thermostat and put in another one. Which one should I put in 160, 180 or 195?

ckhd · 12-11-2003, 12:41 PM

180.

Make sure that the hose from the water pump goes into the bottom of the heater core.

12-10-2003, 01:24 PM	#1
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	Heater question I have a weird situation going on. My heater blows cold air all the time. I have felt both heater hoses after the truck has gotten to operating temperature and they are hot but the heater air is barely warmer than outside air. I have noticed leaves and pine needles blowing out of the heater duct. Is it possible for the leaves to have the heater core blocked and the air is moving around the core without getting heated? It feels like it blows fairly hard, just not warm.I am about to pull off the heater box but that is such a pain in the arse. I doubt I will need a heater much, but when you need it, you need it. Thanks, Darryl

12-10-2003, 01:30 PM	#2
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	Is it non ac? If so, remove the plastic cover that the "hot - cold" cable runs too and check to make sure the flap to divert the outside air thru the heater core is actually working. This is under the dash on the passenger side. The cable has a clamp that will allow your to adjust it. I know these things because it was 10 below zero here this morning. __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

12-10-2003, 03:37 PM	#6
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Burp your coolant system. The stock configuration of the coolant system has excess coolant vented to the ground. After a hot summer you might have lost a bit of coolant so now you have an air bubble. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

12-10-2003, 04:43 PM	#7
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	I just removed and cleaned out my blower box and vents. Man I got about 10 lbs. of crap out of there! There was so much crap in there! You will be amazed by how much junk accumulates in there. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

12-10-2003, 06:19 PM	#8
pierce Registered User Join Date: Sep 2000 Location: Cincinnati,OH,USA Posts: 464	Your thermostat might be stuck in the open position. __________________ 69 GMC 1 Ton Longhorn 37 Chevy Coupe

12-10-2003, 01:34 PM	#3
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	Heaters? What are they used for? :p

12-10-2003, 01:36 PM	#4
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	it is non-ac... Thanks, I 'll check that 10 below... ouch I couldn't do it.

12-10-2003, 01:53 PM	#5
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	Well I think the core must be blocked. I can feel the door move that CPNE said to check. But when it is in the heat position it blows a lot less than when it is in the other position. I didn’t start the truck so I don’t know if the temperature would change depending on the position. I guess I know what I get to do after work tonight. Oh Boy!! I mainly use it for a defroster. I drive less than fifteen miles to work and it rarely gets lower than the low 30’s here The pisser is I did it last year on my 68… ended up selling that truck in the spring…

12-10-2003, 10:08 PM	#9
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	not as much as i expected...it still doesn't blow as warm as thought but it was a big difference... i'll check the thermostat later...thanks guys Attached Images

12-10-2003, 10:47 PM	#10
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	thats quite abit of crap __________________ 70 longbed 496/th400/Ford 9"

12-10-2003, 11:00 PM	#11
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	You should also check to see if you are getting coolent flow through the heater core. If not that would be your problem and you would need to replace the heater core. WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

12-11-2003, 12:35 AM	#12
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	back flush the heater core you will probably get a lot of black nasty looking crap out of it. when i replaced mine the old one was 2 or 3 pounds heavier than the new one because of all the crud that was inside of it __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

12-11-2003, 11:09 AM	#13
Suicide-D Registered User Join Date: Jan 2001 Location: Katy, TX...but the love of my life resides in Dublin,OH. Posts: 1,408	I did back flush the core, several times until the water was clear. I don't think it's getting all that warm. I'll pull the thermostat and put in another one. Which one should I put in 160, 180 or 195?

12-11-2003, 12:41 PM	#14
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	180. Make sure that the hose from the water pump goes into the bottom of the heater core. __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?



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