Deere 135 C Heat Issue (Lack of)

[67kato]

Hi All,

I have an '06 Deere 135C with an HVAC issue. I am not getting the heat to work in the cab. I spent the better part of a day taking out the interior of the machine to get to the HVAC unit under seat only to find that the unit works as it should with the exception of the temperature of the heater hoses. They were luke warm at best. I put it back together and chased the lines back to the motor. There are no valves, just straight hose connections to the block near where the thermostat attaches (in front of and below the thermostat - see pic). I replaced the thermostat and purged the air out of the system per the manufacturers specs. The radiator and overflow tanks are both full. Still no heat??? The temperature gauge comes up quick and stays a little bit above the middle as it has since I bought the machine a few years ago. It has never gotten any hotter and has never given me heat in the cab.

I am going to try and install a piece of clear pipe in the heater line at the engine to see if I am getting flow. I am not 100% on this but it seems like there is air still trapped in the engine? Could the water pump impeller be shot? I don't think so because it would overheat. My head hurts from banging it against the wall.

Confused and cold!!!!

Any ideas.

Tx,
Kato

 

[Delmer]

If you have it all apart, are you sure there's no valve in the line or at the heater core? The only other possibilities are air in the heater core, or the core plugged up. I suppose a radiator hose could collapse inside too, unlikely though. Really it's unlikely that the core is plugged up without swamp water being added to the radiator, have you drained and flushed it ever? what did the drained antifreeze look like, the sediment at the bottom of the bucket especially.

Before you hook up the clear tubing, take both heater hoses off and blow out the core, both ways, with a garden hose and air at the same time or alternating. Run it into a bucket if you can to see what comes out.

 

[67kato]

Tx Delmer. I confirmed there were no valves with the dealer and looked for myself. We got the machine just after the 2000 hr service was performed. I changed the fluid and it looked good. Green and free of sediment. I am going to try and flow test the line with a garden hose and see what happens. My gut is that there is an be air bubble in there. The odd thing is that it should have cleared in the couple of years that we owned and operated it.

 

[lantraxco]

Don't see any valves at all anywhere in the parts breakdowns.... Pretty much gotta be a flow issue?

 

[Delmer]

Check everything. Flow through the core, and coolant out each hose. It wouldn't be the first time something was installed with plugs still in it. Even if it was plugged "completely" with sediment, one hose would get hot, and the other would be lukewarm. This almost has to be something wrong from the start.

If it is air, one way of helping the air work out is to increase the pressure, making the bubble smaller, and the pump less likely to cavitate.

 

[67kato]

Delmer, That's what we will try tomorrow/Saturday. Kw is in there now getting the fluids and filters changed.

 

[67kato]

Lantraxco,
A wish there was a valve and it was broke. That would have been much easier that what we are going through now. It's time for flow testing. Tx

 

[lantraxco]

Worst case, disconnect both lines and blow her out with the garden hose, lol... not too much pressure though, turn the heater core into a sprinkler?

 

[67kato]

That's the plan low pressure! Tx

 

[heymccall]

That machine looks to have a live heater core, so, therefore, heat is regulated by #41 in the drawing. Have you confirmed that the door (#41, Deere calls it a shaft) is actually moving when requested? On my other non-Deere HVAC units, I've had both actuator (#25, Deere calls it a motor) failures, and/ or shaft breakage.
I agree that the hoses should be hot, but actuator or shaft failure has gotten me on many a machine.
Hell, I had a Cat 325CLCR with **** poor heat, and, damned if one of the heater line shipping caps wasn't stuck in the core's inlet tube.

 

[heymccall]

Is your heater hose coming from 69A?