Poor cab heat

[2520tlh]

Ok, I may be repeating what someone else said but.....

Redman:
Looked at your time/temperatures
At 10:51
Engine - 164
Radiator - 78
The outside air is at 39 correct??

Why is the radiator running higher than 39??
I think your thermostat is not closing correctly, or it does not reseat itself.
You should try pinching the inlet to the radiator and see what the engine temps do while its idleing (it should overheat!).
It doesnt take too much bypass to overcool if the fan runs constant.
Sorry if this is a repost.

T.

 

[ShookFarm]

I too thought that temperature value to be intriguing when reading the post. However, it's obvious that you have some fluid thermodynamics at work. With the heater return plumbed into a 'T' into the lower radiator hose, you naturally will get some temperature gradient into the surrounding fluid.

My first reaction after seeing the radiator temp was there is an issue with the thermostat housing/water pump. However, that would surely be obvious to the mechanics. I quickly dismissed this idea.

The bottom line, it appears, is the heater core robs too much heat from the coolant and the engine never recovers unless it's under heavy load. There is no way to fix this unless you find a way to either restrict the fluid flow (as is done by pinching the return line) or by using a water pump that doesn't move fluid quite as fast so it can pick up more heat in the water jackets. Then you create a potential for overheating in the dog days of summer. This particular combo appears to be a knife edge. It's going to be tough to find the balance here.

The other ideas for a thermostatically controlled electric fan or electric fan clutch are also perfectly plausible. But, they don't address the root problem. They would only serve to ease the incidental cooling of the air moving over the engine block.

 

[radman1]

Update:
I think the problem may be fixed. Thanks to turbo36's post from his dealer, my dealer read his post listed on TBN and was able to see the problem. He didn't see it at first. Like turbo36's tractor, mine also had 1"-1.5" breaks in the air box sealant in the top of the cab. He also patched in the defects. Dealer said it was pulling in cold air from the outside right over the heater core. He said you could actually see more dirt around the openings from air being sucked in. The way he explained it, the air box on top of the cab is an open compartment to the heater core and fans. Cold air being sucked in, especially over the heater core, cools the whole box.
My dealer also checked his other 3720 cab on the lot and it also has the breaks in the sealant.
Today I picked up the tractor and used it with temp in the upper teens. Now after light load on the tractor, I can get the engine warmer quicker and get heat out of the cab. Also I can now keep heat coming out of the heater even after engine cools down after warmed up. They also adjusted the injector timing, as it too was slightly off spec. Tomorow the temp is to be in the single digits and I will try it again.

 

[GATOR445]

WHILE THIER IN THERE HAVE THEM CHECK TO MAKE SURE THE CABLE IS ADJUSTED CORRECTLY. IF IT IS NOT THE HEAT VALVE MAY NOT OPEN ALL THE WAY NOT GIVING YOU FULL HEAT OR IT MAY NOT CLOSE IT ALL THE WAY SO THIS SUMMER YOUR AC WON'T BE COOLED BECOUSE YOUR HEATER CORE WILL HAVE HOT WATER RUNNING IN IT. AND THE AC AND HEATER SHARE THE SAME AIR AN THE HEATER IS AFTER THE AC SO IT WILL WARM YOUR COOLED AIR.

 

[GATOR445]

IF YOUR HEATER KNOB DOSEN'T TURN ALL THE WAY BOTH DIRECTION IT WILL NEED TO BE ADJUSTED. FORGOT TO AD THAT TO LAST REPLY.

 

[radman1]

WHILE THIER IN THERE HAVE THEM CHECK TO MAKE SURE THE CABLE IS ADJUSTED CORRECTLY. IF IT IS NOT THE HEAT VALVE MAY NOT OPEN ALL THE WAY NOT GIVING YOU FULL HEAT OR IT MAY NOT CLOSE IT ALL THE WAY SO THIS SUMMER YOUR AC WON'T BE COOLED BECOUSE YOUR HEATER CORE WILL HAVE HOT WATER RUNNING IN IT. AND THE AC AND HEATER SHARE THE SAME AIR AN THE HEATER IS AFTER THE AC SO IT WILL WARM YOUR COOLED AIR.

According to past checks, the heater core valve was working properly. I still may put a shut off valve in the heater hose going from the engine to the cab. From what I have been told, there is always some circulation of water through the cab even if the heater core valve is shut all the way off, via a bypass. Just keeping the heat out of the hoses should help with cooling the cab. The summer cooling seems to be ok. However, it is possible with the leaks in the air box, that I was also cooling outside hot air and the AC may have been working harder than needed.

 

[radman1]

Ok, I may be repeating what someone else said but.....

Redman:
Looked at your time/temperatures
At 10:51
Engine - 164
Radiator - 78
The outside air is at 39 correct??

Why is the radiator running higher than 39??
I think your thermostat is not closing correctly, or it does not reseat itself.
You should try pinching the inlet to the radiator and see what the engine temps do while its idleing (it should overheat!).
It doesnt take too much bypass to overcool if the fan runs constant.
Sorry if this is a repost.

T.

I believe the radiator temp of 78 was correct. With the engine at 164 (measured on the surface), the thermostat had opened. Water then passed through the radiator and increased the temp above the outside air of 39. I only measured the radiator temp after the engine had warmed up.

 

[CATMAN]

Looks like the helpful TBN members can share information faster than the JD factory personnel. Hopefully this is the final solution. We will see how tomorrow goes.

 

[dirtworksequip]

HALLELUJAH,HALLELUJAH..........HEAT AT LAST. AMEN! Now as long as it doesn't throw the Earths rotation out of balance we will all be OK.

 

[radman1]

HALLELUJAH,HALLELUJAH..........HEAT AT LAST. AMEN! Now as long as it doesn't throw the Earths rotation out of balance we will all be OK.

Very funny! Although since the cab heat seems much better, it now has become much colder. Maybe the tilt of the earth changed?
Now if I can just figure out how to get my thermacter valve and draftbobulator to work.....