Poor cab heat

2520tlh · Jan 12, 2007

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 · Jan 12, 2007

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 · Jan 12, 2007

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 · Jan 12, 2007

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 · Jan 12, 2007

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 · Jan 12, 2007

GATOR445 said:
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 · Jan 12, 2007

2520tlh said:
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 · Jan 12, 2007

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 · Jan 13, 2007

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 · Jan 13, 2007

dirtworksequip said:
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.....

dirtworksequip · Jan 13, 2007

radman, you'll have to start a new thread on the thermacter and draftbobulator. Pics will help in solving the problem. Whew........I sure hope its not as tough as the cab heat problem.

p.s. Glad to see you get the heat problem fixed. Now Deere and their dealers should know what to look for. In fact they should put out an update notice.
Sincerely,
DIRT

radman1 · Jan 14, 2007

Ran the tractor past couple of days. Temp near 10. Engine and cab heat now as expected and can maintain the heat. Just finished blading off some light snow. All is right in my little world.

turbo36 · Jan 14, 2007

radman1 said:
Ran the tractor past couple of days. Temp near 10. Engine and cab heat now as expected and can maintain the heat. Just finished blading off some light snow. All is right in my little world.

Yahoo! It looks like Deere engineering came through.

dwmaster · Jan 14, 2007

Congradulations.
The other day I backed my 4320 out of the garage and left it at idle in the driveway for over an hour. It was -21 below with a little wind. When I got back I was shocked to climb in the cab and it was cozy warm in the cab. The controls were not even on high.

ICGREEN · Jan 14, 2007

This is the one thread I've logged on for. I know you're thrilled it's fixed but now what am I going to read??? Anyone else have a nearly unsolvable problem that can be posted? Maybe we should help the President with Iraq.

gemini5362 · Jan 15, 2007

I had some colder weather today it was 22 degrees this morning. I checked the heater on my Montana and got the following results. After 6 minutes it was blowing out warm air from the vents. After ten minutes the cab was starting to get warm enough to be comfortable. I checked this by starting the tractor up letting it sit at an idle and then seeing how long it took to warm up. I did not do any work with it or do anything other than let it sit at an idle. The tractor was sitting outside and the windows were covered in ice. I did close off the vents to the outside fresh air.

BTDT · Jan 15, 2007

dwmaster said:
Congradulations.
The other day I backed my 4320 out of the garage and left it at idle in the driveway for over an hour. It was -21 below with a little wind. When I got back I was shocked to climb in the cab and it was cozy warm in the cab. The controls were not even on high.

Was this a test or did you forget that you had cranked it up?

dwmaster · Jan 16, 2007

Yes...... I forgot that I had backed out of the garage. I can't believe you figured that out, I should of known. I backed it out of the garage to get the skidsteer out. I used the skidsteer to load the sander to go sand a driveway real quick then return and use the tractor to go do some driveways in the area. Well I got sidetracked and didn't remember it was in the driveway running till I got back. With the 50 50 blend fuel in the tank I was pleased to see it was still running considering it was at a low idle.
Anyway you proved that this is a very clever bunch not much gets by U's.

turbo36 · Jan 28, 2007

I finally got a chance to try out the tractor after the dealer fixed the roof seal. Wow, what a difference! After a 15 minute warm up at 1,500 rpm I ran it up to 2,700 and started to blow snow, within 5 minutes I had my jacket off and was turning the heat down. I am now a very happy camper.