Poor cab heat

[radman1]

Let us know what result you get. My guess is it won't make any difference. Both thermostats will remain closed because the engine heat won't get high enough to open either one. Although I will admit, that the heater should put out a warmer air at operating temps with a hotter thermostat. I am not impressed with the heat coming out of the heater currently with the lower Temp thermostat.

 

[turbo36]

Let us know what result you get. My guess is it won't make any difference. Both thermostats will remain closed because the engine heat won't get high enough to open either one. Although I will admit, that the heater should put out a warmer air at operating temps with a hotter thermostat. I am not impressed with the heat coming out of the heater currently with the lower Temp thermostat.

I agree but I have to let them try, I will be surprised if it works.

 

[radman1]

Update. Service dept. picked up my JD 3720 and went over it with the regional rep. It performed worse for them getting cab heat than in the past because the temp is now in the low 20's and the engine was not even close to getting warm. They repeated all the things that were tried in the past. Checked for air block, heater control valve, took various heat readings in the cab at the vents, engine temp. etc. At least the regional rep is getting involved. Rep wants to try a hotter thermostat. Both service manager and I think it won't help but will give it a try. Service manager is going to JD meeting in Tampa, FL next week and will try to get some answers. Next plan by service manager is rerouting the hoses if hotter thermostat doesn't work.

 

[turbo36]

Update: The dealer e-mailed me and said the problem is solved and I should have no more issues. They replaced the 160 degree thermostat with a 180 degree as that has worked in the past for poor cab heat issues. According to the dealer with the new thermostat the tractor warmed up in about 10-15 minutes and the heater "would blow you out of the cab". Well, at first I was excited until I realized they tested it in near 50 degree weather so it wasn't a good test. I thanked them and said I would test it on the first cold day.
We got 8 inches of wet heavy snow on Friday so this was my chance to check the "fix" my dealer performed on my tractor.
I started the tractor and drove it out of the barn into the 32 degree weather and waited 20 minutes with the tractor at 1,000 rpm. Unfortunately the results were not the same as the dealer's; the needle on the temp Gage moved about 1/4" from rest but the air temp coming out of the heater ducts was 66 degrees. I ran the tractor up to 2,500 rpm and started blowing snow, after a few minutes the needle moved another 1/8"- 3/16" and the air temp increased to 80 degrees. This is an improvement but certainly not enough if it gets really cold.
Later in the day when the temp moved up to 38-40 degrees the needle moved another 3/16" and the heater air temp increased to around 100 degrees.
It is pretty clear to me that quite simply they have too much capacity to get rid of heat.

 

[Labrat]

I replace my radiator screen with an aluminum panel with 4, 2” holes drilled in it for the winter months. The coolant temp went from 125 at idle to 165 at idle and 185 under load. I think these jd rad fans super cool the block with all the air they move along with the efficiency of these new engines the coolant temps are to low with no engine load.

 

[radman1]

Update: The dealer e-mailed me and said the problem is solved and I should have no more issues. They replaced the 160 degree thermostat with a 180 degree as that has worked in the past for poor cab heat issues. According to the dealer with the new thermostat the tractor warmed up in about 10-15 minutes and the heater "would blow you out of the cab". Well, at first I was excited until I realized they tested it in near 50 degree weather so it wasn't a good test. I thanked them and said I would test it on the first cold day.
We got 8 inches of wet heavy snow on Friday so this was my chance to check the "fix" my dealer performed on my tractor.
I started the tractor and drove it out of the barn into the 32 degree weather and waited 20 minutes with the tractor at 1,000 rpm. Unfortunately the results were not the same as the dealer's; the needle on the temp Gage moved about 1/4" from rest but the air temp coming out of the heater ducts was 66 degrees. I ran the tractor up to 2,500 rpm and started blowing snow, after a few minutes the needle moved another 1/8"- 3/16" and the air temp increased to 80 degrees. This is an improvement but certainly not enough if it gets really cold.
Later in the day when the temp moved up to 38-40 degrees the needle moved another 3/16" and the heater air temp increased to around 100 degrees.
It is pretty clear to me that quite simply they have too much capacity to get rid of heat.

Update. JD service manager is coming to my place to change out the thermostat tomorrow. I know that you changed out your thermostat but still didn't get good results. My service manager and regional rep said the thermostat to use is sort of special for this problem and not the typical, hotter, JD thermostat. He said this one will allows a little bit of flow before it opens, opens more slowly and is a higher temp thermostat. It is suppose to help this problem. They knew of someone in Michigan who had the same problem with poor cab heating. I thought that might be you!(turbo36) He said a dealer in MI changed a thermostat in a 3720 recently but they think he didn't use they correct replacement thermostat. Could that be you?
I'll let you know if the problem is fixed.

 

[turbo36]

Update. JD service manager is coming to my place to change out the thermostat tomorrow. I know that you changed out your thermostat but still didn't get good results. My service manager and regional rep said the thermostat to use is sort of special for this problem and not the typical, hotter, JD thermostat. He said this one will allows a little bit of flow before it opens, opens more slowly and is a higher temp thermostat. It is suppose to help this problem. They knew of someone in Michigan who had the same problem with poor cab heating. I thought that might be you!(turbo36) He said a dealer in MI changed a thermostat in a 3720 recently but they think he didn't use they correct replacement thermostat. Could that be you?
I'll let you know if the problem is fixed.

It probably was my tractor, they just used a standard hotter thermostat, nothing special.

 

[radman1]

Turbo36
Had different thermostat installed today. Temp today was 50, so I don't know if it made much of a difference. My gut feeling is it is the same as before. I did buy a infrared temp gun from HF. The temp at the thermostat housing was 158 after running for 20 minutes. The thermostat is suppose to open at 180 and my guess it is not getting hot enough to open the thermostat. However, under load, the tractor temp gauge now goes slightly higher and the heat blowing out of the heater feels warmer as expected. Next cold day will be the real test.
The new thermostat looked exactly like the old one. The part number for the new thermostat was M811601.

 

[CATMAN]

Thanks for the update radman1. I am still following this thread. You just need a good 20-30F day to test it at idle to 1500 rpm with no load applied to the engine, then see what temperature the cab heater puts out. Did they mention anything about "water hammer" affecting the original thermostat? If this works, I am just trying to find the logic or reasoning if this repair cures your complaint.(seeing how the original t-stat tested OK) I guess we will just wait and see.

 

[wolc123]

What will you do next summer, put the 160 thermostat back in? Would not the higher block temperature, especially with the additional air-conditioning load, shorten engine life?

 

[radman1]

What will you do next summer, put the 160 thermostat back in? Would not the higher block temperature, especially with the additional air-conditioning load, shorten engine life?

I don't think overheating will be an issue. I ran the tractor this summer on 100F days while bush hogging. The temp gauge would climb to just over 1/2 way to the red zone. Overheating doesn't seem to be an issue with this tractor. Using the tractor today with moderate load, the temp gauge climbed to about the same level as when I used it this summer during the heat. At 180 the thermostat should open fully. A tractor that overheats with a 180 thermostat will likely overheat with a 160 thermostat. It is probably more detrimental to a diesel engine running at too cool of a temp than running at 180-200. A 160 thermostat seems almost too low. I believe most auto thermostats run in the 180-200 range.

 

[gemini5362]

After reading in your post that with the heater return line clamped the engine warmed up it reminded me of an emergency fix for autos. If you have trouble with your car overheating on a very hot day you can turn the heater on high and that will allow the heater core to act like a small radiator and sometimes it will give you enough extra cooling to get where you can get it fixed. Sounds to me like you are having kind of a reverse problem when heater is on gives too much of a radiator and cools the engine down. If you have the heater set to off or the coolest heat temp etc what does that do to engine temp. If engine temp is more normal with it off. I would ask the dealer to try a cheap easy temp fix to see if it helped. get some fittings and adapt the heater return line down to where it runs through some 1/8 inch metal tubeing (as in plumb in a 1/8 inch bell fitting and then go back to regular heater hose size.) hopefully this will slow down the flow through the heater core. If that works then with the dealers blessing you could keep it in place and be an easy fix while JD is coming up with a permanent fix. If by some chance it works and JD uses that for a fix I want to know about it so I can ask for royalties.

 

[dwmaster]

Restricting the flow through the Heater will not acomplish what he wants to do which is get more heat in the cab. He is not trying to maintain heat in the engine!!!!! If he wanted to do that he could just leave the heater shut off. The real issue is the motor is not produceing enough heat to provide some extra heat for the cab.

 

[gemini5362]

DWMaster maybe you should read my entire post before you post your comments. I believe I explained in my post that the problem might be the heater core was acting as an addtional radiator which was providing an extra amount of cooling. When I read his earlier post I noticed that when he clamped off the return heater hose he mentioned that engine temperature went up. For what ever reason it might be. The physical indications are that restricting the water movement through the heater core caused the temperature of the motor to increase. My idea was expanding on that observation. Do you perhaps have a better idea for him to try ?

 

[gemini5362]

I did clamp my heater return hose yesterday with a vise grip and then started the tractor cold at 29F and windy. At fast idle the temp gauge was 1/2 way over (in the green range) in 11 minutes. Removed the clamp and temp began falling a 1-2 minutes to 1/4 way over. Took tractor out and did hard blading work for 10 minutes and heat went back up to 1/2 way and heat in the cab. Worked tractor for 10-15 more minutes then let it idle. It took about 15 minutes to eventually cool the engine/water back down and blow cool air again in cab.
.

DWMASTER
This is the part of his thread i was responding to

 

[radman1]

After reading in your post that with the heater return line clamped the engine warmed up it reminded me of an emergency fix for autos. If you have trouble with your car overheating on a very hot day you can turn the heater on high and that will allow the heater core to act like a small radiator and sometimes it will give you enough extra cooling to get where you can get it fixed. Sounds to me like you are having kind of a reverse problem when heater is on gives too much of a radiator and cools the engine down. If you have the heater set to off or the coolest heat temp etc what does that do to engine temp. If engine temp is more normal with it off. I would ask the dealer to try a cheap easy temp fix to see if it helped. get some fittings and adapt the heater return line down to where it runs through some 1/8 inch metal tubeing (as in plumb in a 1/8 inch bell fitting and then go back to regular heater hose size.) hopefully this will slow down the flow through the heater core. If that works then with the dealers blessing you could keep it in place and be an easy fix while JD is coming up with a permanent fix. If by some chance it works and JD uses that for a fix I want to know about it so I can ask for royalties.

If I turn the heater control valve down completely the tractor will warm up more but still not up to operating temp. My understanding is that there is always some flow through the heater core even when the valve is turned down. I have tried partially clamping the return hose. This will reduce the return flow and help heat the tractor. However, now less flow goes through the heater core and thus less heat is put into the cab. Net effect is warmer engine but not enough heat in cab. At one time we considered putting a valve in the heater hose and partially closing it but the net effect would be the same. I need a hot engine and hot cab.

 

[gemini5362]

That makes sense I did not think about recducing the flow would reduce heat in heater but actually that is what the temp control does duh.

I dont remember all of the posts but have you completely totally enclosed the front of your radiator. I know you said you did not want to have to do that on a 30,000 dollar tractor. My list price 48,000 dollar silverado actually has a cover to do just that for cold climates. It covers everything so no air comes in the front of the truck just what it gets underneath

 

[dwmaster]

No I Don't.
Interesting observation on my 4320 the other day. I was out when it was -5 below and -40 with the windchill. I shut the heater off for a while then turned it back on. The temp gauge climbed and then fell at least 1/4 to 3/8 of an inch. That heater system and core robs alot of heat! The good news is is even at those temps I had the fan and temp on low.

 

[tglass]

I've got to hand it to you for your patience. If it were my tractor, after all this time I'de be steaming when I walked in to the dealer, He and Deere would probably be so tired of me calling they'de probably offer to give me my money back. I'de still refuse. This is getting interesting. Got to hear the outcome.

 

[radman1]

I've got to hand it to you for your patience. If it were my tractor, after all this time I'de be steaming when I walked in to the dealer, He and Deere would probably be so tired of me calling they'de probably offer to give me my money back. I'de still refuse. This is getting interesting. Got to hear the outcome.

The first time I talked with them, I was getting a little mad. But they have really been trying to help solve this problem. Also the weather has really been good to me so far this year. Cab with poor heat is still much better than sitting out in the wind and a lot quieter. On a cool, sunny day, the amount of solar heat through the windows does a good job of making it comfortable in the cab. Suppose to be in 30's this weekend and will see how it performs in colder weather and hotter thermostat.