No heat in Hiniker cab

deere3715

New User
I have a 1971 4020 that I recently purchased and intend to use to feed round bales in the winter. It has a Hiniker cab that I cannot get heat out of. I have flushed the heater core, lines, and cooling system and added new coolant. I have also installed the high temp thermostats and put cardboard in front of the radiator. The shutoff valve going into the core opens and closes properly. The high temp line is plumbed into the top of the oil cooler and the return line goes back to the lower hose. The tractor was run at 5 degrees F today and blows ice cold air at idle and cool air at throttle up. I can feel warm coolant going into the core and barely warm coming out of the core, so I know it is circulating to some extent. I would only like to get enough heat out of this to keep the windows clear in the cold weather. Any help would be appreciated.
 

If all else fails temporarily splice a length of clear tubing into the hose that feeds the heater and watch what's going through the hose while the tractor is running. Lots of bubbles means compression is getting into the cooling system. Bubbles don't transfer heat well. I suppose it would work on the return hose too.
 
I had the same combo decades ago on a "67 4020. Wondering about being airlocked....air in the system. You"re obviously getting some circulation, but not enough. Had that on a 65 Mustang once......flooring it down the road cured it, but how do you do that on a 4020? I can"t remember where the hoses hooked into/out of the system, but I don"t think it got flow from the oil cooler....maybe nearer the water pump?
 

Here's the parts schematic how JD plumbed the heater on the 4020 factory cab. i was thinking one end should be plumbed into water pump or thermostat housing tubing.
mvphoto13535.gif
 
I am going to check for combustion gases in the cooling system just to be sure the head gasket isn't leaking. Also the water tube by the thermostats does warm up faster than where it is currently tapped into on top of the oil cooler. Don't know if there would be more circulation by the water pump than by the oil cooler, although the oil cooler is fed from a tube going directly to the water pump. Would anyone know how to get an airlock out of the system should that be the problem. The current system appears to have been in place for many years, so I would assume it had to have worked.
 
I assume by the "valve going into the core" you mean the one that's connected to the pull switch on the dash that says "pull for heat"?

The only thing I could add is to make sure that your lines are hooked up so that the pressure side of the pump goes into the heater core, and the outlet follows the route leading back into the radiator. If it doesn't circulate correctly, you won't get spit. You may be getting only gravity fed warm water.

I have a Hiniker on my 3010 with a pretty small inlet line (3/8) and the heater works great. It was the easiest hookup without putting on a new water pump.
 

I have no idea what you have tapped into for supply. As previously stated the heater core must be supplied with the hottest and highest pressure coolant in the system. That would be just prior to the thermostat(s).
Coolant must be returned to the lowest pressure point in the system which is the coolant pump inlet.
What is the actual coolant temperature?
Is there a block heater being used to warm the engine before starting?
 
I have replumbed this like recommended. I have tapped into the front bypass tube by the thermostat housing, instead of by the oil cooler as was previous. The return line is plumbed into the lower hose. I am getting zero fluid flow with this set-up. I had the operating temp to the point where you could barely touch the bypass lines by the thermostat. I also took the return line off and sucked coolant all the way through the system and reconnected and still no flow. I am considering looking for a coolant pump to put inline to assist in pumping. Any other ideas?
 
Is there a chance your core is restricted? It wouldn't be unheard of. You may be getting "some" flow through it but not enough to transfer much heat. Something to check. Mike
 
The core was taken out and flushed with a garden hose. It flowed freely in both directions. I'm not even getting flow to the heater core.
 
Was the core and lines flushed with the valve and all lines connected together?
How much flow is there from the coolant pump? Is the impeller worn and the tractor is mostly thermal cycling by gravity?
 
As long as the heater valve is open. Supplying the heater core from the coolant bypass line should provide the highest pressure and most heat.
Just plumb the heater core in series with the bypass line and cap that port at the intake hose.
Can you post a picture so we can see what is what?
What is the actual coolant temperature ?
 

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