The Stovebolt Site Forums The Shop Area Engine Shop Heater stopped working, 54 3100

I drive my 54 maybe 1,000 miles a year. A couple years a go the heater stopped getting warm. Now it is getting cold in PA and would like to drive it more.
Any ideas on what I need to fix to get heat?
Thanks

Does the temp gauge show that the engine is heating up? If not the the thermostat may be stuck open.

If the engine is getting warm (180) or so degrees then perhaps the heater core is stopped up not allowing the hot coolant to flow through it.

Does it have enough coolant in the radiator? If it is low it won't circulate to the heater very well.

My bet is a stopped up or plugged heater core.

I assume you do not have a shutoff valve in your hose going to the heater that might be in the off position? Just sayin....

After being sure all the valves are open, try reverse-flushing the heater core. Adapt a garden hose to the heater system, and run water backwards to its usual flow. The return line for the heater core generally gets attached at or near the water pump, so make that hose the "input" line during flushing. Let the other line run free- - - -don't flush the crud back into the cooling system. Also be sure you install a 180 degree thermostat- - - -a 160 won't get the coolant hot enough to provide much heat to the cab.
Jerry

Thanks Guys,
The 2 hoses coming off the heater control valve are hot. The one coming fron the heater core to the thermostat housing is cool. Does that mean my heater core is clogged?

Yes... if there are no valves in the hoses, that's a good sign a little bit of heat is getting in, but is severely restricted by a clog so that by the time what little gets through it's cold.

Thanks Roy,
Can I back flush the core or do I have to have it professionally redone?

Gunner - you can give it a flush yourself, but be ready for the leak inside that may well happen afterwards always a good idea to take the core to a shop and have it cleaned because they'll pressure test it and catch the leaks before they happen

Bill

As red58 said, you can back flush it. Just be ready. Sometimes they will leak. But certainly worth trying. If it does leak, take it out and have a radiator shop fix it.

If you get lucky and it doesn't leak, you'll have heat.

I wouldn't turn full hydrant pressure on it though, a little at a time to get things flowing. Then you can allow more to go through.

But if you hit it with full hydrant pressure, you may be assured of a leak. Those old cores only had around 7lbs of pressure on them.

if you have no flow,the hoses to the heater control valve won't be hot, the water has to be moving through the hoses to make them hot. With the exception of a little conduction. according to the factory installation instructions no hose should go from the thermostat housing to the heater core, it goes from the pump to the heater, out of the core to the control valve, then to the thermostat housing. look on the old online chevy manuals, it is in accesories or something. It isn't acutally in the shop manual. make sure you have it plumbed correctly.

where in eastern pa are you located?