Good Full size truck forum

[PaulT]

I am having some problems with my 97 Chevy 3/4 ton heater. When I have problems with my tractor, or anything remotely connected to tractoring, I just ask this wise group for advice. Does anyone know of a similar web site for full-size (chevy) truck help? Maybe someone here might even know what I should do.

Heater stopped putting out as much heat as it used to late summer. I didn't worry about it then, because it was summer. Now its winter and I miss the heat. It still gets warm, but not hot. I can smell anti-freeze a little when the fans on high, and its really strong outside (if I roll the window down at a drive-thru, for example). The temp gauge runs normal (cycles between 140-195), so I didn't think it was the thermostat. The fluid level doesn't change, so its not leaking anywhere. Just today I find out there's a heater valve available for the truck (parts america online says so). This looks like a valve to close off the heater core from hot water flow. I never knew such a thing existed, or was factory installed on my vehicle. If my k2500 350 cid truly has one of these, it seems like it could be partially stuck. Any ideas??? Do I really have a heater valve, and whats it do, how/when does it activate?

PaulT

 

[Bird]

PaulT, I'll be watching for the responses on this since it really makes me curious. The only times I've seen such a problem that included the odor of antifreeze, the heater core was leaking (but you say the fluid level hasn't changed - that puzzles me). And yes, you definitely have a valve that regulates the flow of the coolant through the heater core. Trouble is, I don't remember enough about that model to help you./w3tcompact/icons/frown.gif

 

[Chuck52]

I had a similar problem with my Dodge caravan. The temperature guage looked OK....started cold, went to normal range....but I was getting no heat. I had it at the dealer for something else and they got error messages from the computer about the thermostat. New thermostat, good heat. The temperature guage still looks the same. Maybe it's like the thermostat on the wall of my office. It's there for decoration so far as I can tell. Anyhoo, thermostats are cheap.

Chuck

 

[therrien]

Paul
If you smell coolant the heater core is most likely leaking. Check the floor and under the dash on the passenger side. There is a valve to regulate the water flow through the heater core. It would be seen on one of the 5/8" or 3/4" hoses under the hood near the fire wall. If your temp adjustment on the dash is a slide knob, the valve would use a cable to activate it. On GM's this cable disconnects from the valve or from the mechanism on the dash. Once you find the valve you can turn it with pliers tempararily to the hot position until you can repair it.Once this valve is open, the temp. of both inlet and outlet hoses of the heater core should be about the same.If they are not, and your sure the valve is open, the heater core is most likely part way blocked. Sometimes back flushing the system can clean them but not allways.
You should also check your coolant at the radiator when it is stone cold. Checking at the overflow bottle is not acurate if there is a small leak in the system.


Doug T B1700 TLB

 

[Russ]

Heres a site you might try

http://gm-trucks.com/

Russ

 

[Molerj]

I had a friend that had the same problem in his car. Turned out after much searching that
the heater core was partially plugged. Went to a radiator shop & they flushed it out & it
is working fine. You may want to try http:// www.wrenchead.com

 

[Molerj]

Let's try this instead http://www.wrenchead.com & then go to under the hood. You will have to sign up to go to the
message board.

 

[Gatorboy]

<font color=blue>I am having some problems with my 97 Chevy 3/4 ton heater</font color=blue>

Boy, that is one heavy heater. /w3tcompact/icons/smile.gif

Dave "Gatorboy" Hoffmann

 

[PaulT]

Always good for a chuckle.Thanks for lightening my spirits. /w3tcompact/icons/smile.gif

PaulT

 

[Wheeldog]

Paul,

I don't drive a Chevy, but I've found the best information on my truck from the bulletin board on www.off-road.com (and not just about giant tires and lift kits /w3tcompact/icons/smile.gif). The guys who are on that board tend to be people who've done a lot of work on their vehicles and have seen or heard most any problem you can think of. I don't know anything about the Chevy guys, but I know that there are a lot of them and maybe they can help.

http://www.off-road.com/chevy/

Rob

 

[rdln]

Also look at inside of windshield for a haze created by mist coming from defroster. I had an s-10 with a core that went at 50k miles, dealer labor was quoted at $400 found a gmc mechanic to do it at his home for $200. An all out failure of core might be an unpleasant surprise as hot coolant comes out of vents.

Steve
Champagne Taste, Beer Budget

 

[mwagoner]

PaulT
Give thisa try I have had a lot of luck looking for problems with my 96 k1500.
http://www.pickuptrucks.net/pickup_truck/Posting_Boards/

I can't get it make a link/w3tcompact/icons/frown.gif

Matt

 

[Rch]

I had an '89 Lincoln that wouldn't put out heat despite a functioning tempature gauge that indicated normal operating temps. The heater input was tapped off the head of the engine (a crossways V6) The long and the short of it was a head gasket leak into the water jacket that would block(vapor lock !) the take-off port for the heater. Revving the engine real high would overcome the resistence the bubble of exhaust gases caused and the flow would resume temporarilly through the heater. Fortunately it was under warranty and was a $880 bill circa 1996. The Ford garage screwed around for 2 months with thermostats, electronic/vacunm controls.

RCH

 

[PaulT]

The mystery has been resolved. The heater core was fully blocked by calcium-like deposits. No water was flowing in. There is no valve on the heater hoses on this truck (97 3/4 ton). On my 96 1/2 ton Tahoe, there is a valve. The thermostat was working ok, but I changed it anyway, and there was a lot of crud on it (probably from whatever clogged the heater core). The thing that really ticks me off is that I paid a local Chevy dealer over $500 to replace the heater core less than 2 years ago. My buddy at the radiator shop can't understand how this could have happened if they really did replace the core AND flushed the system sufficiently. Don't trust those dealerships as far as I can throw them!!!/w3tcompact/icons/mad.gif

The smell of antifreeze is coming from a small split where the cooling fins of the main radiator come together with one of the side tanks. It was loosing level ever so slightly, but the crack is pretty high up on the radiator, so it only leaked steam after the level went down below that point - not a lot of volume, but pretty easy to smell. The smell was being picked up by the fresh air intake as the heater blew (cold) air into the truck. Since the radiator has plastic tanks, it cannot be brazed, so after I use up the antifreeze I have topping off the reservoir, I will probably spring for the ~$300 to replace the radiator. I'm not in the mood to do it right now since my other car (96 tahoe) just got a new intake manifold since the old one cracked where a water passage was (leaking anitfreeze like a sieve). When it rains, it pours./w3tcompact/icons/sad.gif