Heater not working (1 Viewer)

[mixmaster]

I am pretty much an 80 newbie, I've only had it for about 3 months now. Anyways, I searched but didn't find any info, so, sorry if this is a dumb question.
My heater doesn't work, that is about all there is to it. Is there a heater valve somewhere that could have gotten closed to keep some heat out in the summer. My brother in law closes his heater valve in his 40 in the summer, so I was just wondering if there was something similar on the 80. Any other suggestions or comments appreciated. Thanks.

 

[Rich]

Yes, there is a heater control valve. For a picture, you can go to https://forum.ih8mud.com/showthread.php?t=6845&page=3. The picture labled coolant feed depicts the heater control valve slightly obscured by a coolant line that your truck will not have. The heater control valve is located in the picture on the firewall above and behind the vacuum valve that has the large green label. It is cable operated.

 

[mixmaster]

Right on, thanks man. I wonder if the cable is stuck or something like that.? Guess I will have to play around with it a bit. Any other suggestions? Thanks again.

 

[Rich]

If heater valve is operating ok then heater cores are clogged. Heater cores are best flushed by removing the inlet and outlet tubing and directly back flushing through the outlets with a garden hose.

The picture labled coolant filter in the link I posted above shows the heater core outlets. They are in the upper right hand corner of the picture. The front heater core outlet is above the rear heater outlet. They both join with a tee and connect to the metal pipe running above the exhaust manifold. The metal pipe goes to the water pump inlet.

 

[mixmaster]

Sweet, thanks again man. I need to get this thing going before it gets much colder.

 

[mixmaster]

Just thought I would post my findings in case anyone runs into this later down the road, hopefully this can help them. What happened was the cable that connets to the valve disconnected so it wouldn't open the valve. Pretty simple, just hooked the cable back up.

 

[Heffenoche]

Does the 80 thermostat have two gaskets like the 2f engine cruisers? If it does then it's possible that someone replaced the thermostat w/o the second gasket not allowing thing to warm up correctly and the heater won't work.

 

[CDN_Cruiser]

I had the same problem (and posted the same fix) - one thing that you should check RIGHT AWAY is if the cable has damaged the wiring harness cover and eaten into the wiring harness.

When I reconnected mine, I found that the cable had rubbed through the heat shielding on the wiring harness. If any of the harness is damaged /shorted, you will get some really strange things happening that are hard to diagnose.

Cheers, Hugh

 

[firetruck41]

I was able to fix my intermittent heat with good coolant flush, I didn't flush the heater core specifically, but it must have gotten enough "gunk" out to restore flow.