Heater sucks!!!

[webfoot]

It has been getting pretty cold around here lately, the last couple days the high temp has gotten clear into the low 20s. My heater seemed like it worked fine in the fall but as I was driving on the freeway in some thick fog it was freezing to the windshield and the defrost vents felt like they were blowing out 60 degree air. I was still pretty chilly despite having an arctic carhartt jacket on.

I would not think the cold air would keep the coolant THAT cold, does this sound more like a nearly plugged up heater core?

[70cst]

I would think there is an issue as you should be getting heat...

Ideas fellow board members?

[domeier]

Might want to take a look at the firewall, too. Plugging up all the air leaks makes a big difference.

[trev1]

Sounds like the thermostat is stuck open. Engine is not getting up temp. Replace the thermostat and see if it helps.

[Bert W]

I was thinking a stuck thermostat also, or nor thermostat, or a low temp. thermostat. I like the plugging the holes idea also.

[webfoot]

Hadn't thought about the t-stat, that makes sense though.

[PanelDeland]

Could also be a clogged heater core.Take the hoses loose and run the water hose thru it.Flush both ways.Especially if it's a newer replacement.For some reason they have made the lines thru them smaller and they clog easier.

[trev1]

Yep...less than 20 bucks and less than 20 min.. first place I would start....IMO

[cdowns]

i'd take the blower motor out and check to seee if the phlenum is clogged with 40 years of crap causing no air circulation

cost is $20 less than that $20// i've found time with no money is better than money alot of times when solving problems

[oldblue1968chevy]

im with cdowns

[slikside]

Originally Posted by cdowns

i'd take the blower motor out and check to seee if the phlenum is clogged with 40 years of crap causing no air circulation

cost is $20 less than that $20// i've found time with no money is better than money alot of times when solving problems

This certainly won't hurt, but it won't help it get hotter. How is the airflow? If you can feel some volume coming through, it's not the blower. I'm inclined to think more of a core blockage or the thermostat.

[VetteVet]

If it sucks then the motor is running backwards.

sorry J/K

First thing is check the air flow from the vents. Then check the lever on the heat door control for free travel no binding. Then check the top and bottom heater hoses after the engine warms up for equal temperature both warm to hot. If you have AC then the control valve might be stuck on the inlet hose to the heater core.

[webfoot]

Air volume is decent, I'd say similar to what my chevelle puts out. Still what I would consider inadequate, but I think thats about as good as these ol things get.

[Dark Knight]

If your engine isn't getting up to operating temp, try blocking half of the radiator with a piece of cardboard. Watch your temp gauge though. I've got a 160 t-stat in mine, but didn't change it before winter. Now my truck barely warms up. The cardboard works. (Then I noticed all the big-rigs with the snap on covers over the front of their trucks.)

[1972RedNeck]

Originally Posted by webfoot

Still what I would consider inadequate, but I think thats about as good as these ol things get.

These trucks have HUGE heater cores. I've got a little laser-pointer-thermometer-thingy-mabobber and it says my output air temp is 145* on a 30* day. I have a 180* thermostat.

[z10kl]

Is the air comeing out warm at a low fan speed and then cools when you turn the fan to high? If so the core is clogged and the air is cooling it faster than the water can move though it. Mine was doing this and I removed the hoses form the motor and took a hose and blew through it backwards. At first hardly any water would go through. Then some grit and rust started coming out and I could tell The flow was getting better. Heats better now.

[special-K]

It must be in the thermostat. You're not "making" heat. These trucks have heaters that are second to none. They put out more heat than you will ever need. If the heater core was clogged you'd feel a hot heater hose going in and a cooler one going out. If the plenum was clogged you'd still have the heat,just less air bowing through. In fact,you'd have a very hot heater. I never wear a jacket while in my truck and it's rare the fan is ever blowing more than low. It only goes on high to deice when I first start it up or to defog when I get in the truck wet. Then,the temp is either set down or if it's on hot to dry the air I need to open the wing vent or crack a window. A proper working heater will make you sweat like a pig with fan on high and temperature set on hot.

[franks72]

This is what I found in mine.
http://67-72chevytrucks.com/vboard/s...d.php?t=396843

[trev1]

Webfoot,what did you find? Would sure like to know.

[webfoot]

Haven't played with it yet. We haven't been above freezing for about 2 weeks now so my motivation to go out and work on it is low. I will update the thread when I find out.

[Mudder]

Low water/anti freeze mixture. Make sure it has plenty of water in it. After I redid my heater with new door rubber it would actually run you out.