Poor cab heat

[radman1]

mike311
I feel this is much more than air in heater core. Air in the heater core would not explain an engine temp of 113F after fast idle for 15-20 minutes but rise of temp to 146F after clamping return heater hose. Engine temp then rapidly falls back to 113F after unclamping return heater hose. No way air in the heater core would do that. A control valve problem on the heater would also not do that. With the control valve off the hot water from the feed hose would still bypass to the return hose.

 

[CATMAN]

Well it sounds like the JD 3 cylinder engine doesn't generate enough heat on cool to cold days under light loads with the amount of block and front of engine casting "surface area". That surface area is losing the little available heat that the engine has under light load. Note: A heater core is just a little radiator and when you clamp off the that heater hose, you eliminated the heat loss that the heater core would remove. Thats why the engine temperature climbs to 146 degrees F. Sounds to me like JD will have to manufacture and apply external engine block insulation to both sides of the engine and to the front of the engine and possibly the oil pan. Along with this, they may need to remove direct-drive engine fan and replace it with a thermostatly controlled DC electric fan or electric fan clutch on direct-drive fan. The biggest issue for JD warranty dept and their engineers will be the cost to retrofit all tractors/customers that have these complaints($$$$). I wonder if they may try something like a DC electric heater on the heater core(but these may overwhem their stock alternator and electrical system). I sure JD was hoping that cardboard in front of the radiator would help=cheap. If too much surface area is the cause; I suspect you may be in for a long waiting period if the solutions cost too much. As one other poster mentioned, I am surprized that JD hadn't done cold weather testing in a cold room or testing in Canada or Alaska for these types of possible complaints before releasing their product to the public. I have been to PACCAR's Tech Center(Kenworth and Peterbilt) in northwest WA. I"ve seen their cold room and if memory serves my correctly, it would achieve -40 to -60 degrees F. A simple test of removing the fan (but keep the pulley attached to the water pump and the belt on to drive the water pump) then run the engine. IF no improvement, then with the fan still off, add cardboard to both sides of the engine compartment to hold in the heat, but don't let it touch the exhaust system. Retest and see if there is improvement.I don't expect you to do this, as the tractor is still under warranty, but I would think someone in the JD organization would be trying different ideas, even if they are a temporary measure until JD Factory comes up with a more permanent solution.

 

[minimax]

I think deere tested the heat because the web,video say you can change the temp in the cab 30 deg in 5 min. checkout the build and price part under a 3720 on deere's website and click on the camara.

radman and turbo how many hour on the meters??

minimax

 

[JasonMac]

Well it sounds like the JD 3 cylinder engine doesn't generate enough heat on cool to cold days under light loads with the amount of block and front of engine casting "surface area". That surface area is losing the little available heat that the engine has under light load.

My 3Cylinder Engine generates enough heat. I can start my tractor on the coldest of days, sitting outdoors... let the tractor idle with the heat on and within 7 minutes the heat is up to par... and that is from outside temperature to very warm. 7 minutes!

Now if I cold start the tractor and use it under some load within 5 minutes the heat is very comfortable, even on the coldest days last winter. After 10 to 15 minutes you could operate the machine in your T-shirt and be comfortable... so I guess I got lucky because my 3cylinder engine generates enough heat.

 

[turbo36]

I think deere tested the heat because the web,video say you can change the temp in the cab 30 deg in 5 min. checkout the build and price part under a 3720 on deere's website and click on the camara.

radman and turbo how many hour on the meters??

minimax

6 hours.

 

[radman1]

I think deere tested the heat because the web,video say you can change the temp in the cab 30 deg in 5 min. checkout the build and price part under a 3720 on deere's website and click on the camara.

radman and turbo how many hour on the meters??

minimax

30 hours on tractor.

Update. Service manager said they have another customer's cab tractor with same problem but they just got a 3520 cab in that seems to be fine at this point. They haven't heard back from JD yet. He says there are some other threaded plugs in the block that he thinks are clean out/flush plugs. We might be able to tap into one of these for the return line. He is also considering putting a valve restrictor in the return line to see if this can help if the problem is due to pump circulating water too fast.
Even with the control valve on the heater turned off, the engine won't heat up. The heater control valve when off diverts the water from the heater core to a bypass and then returns the water by the return hose. If the heater core was removing too much heat, the tractor should heat up with the heater control shut off, which is not the case. (However, the engine will get about 5 degrees warmer with the heater valve shut off.)

 

[Willl]

Just a thought, maybe using some sort of restictor(sp?) in the heater hose.

Should be simple to simulate, just partially kink the hose.

 

[tglass]

Something must be different in the engine water jacket on the 3720. My 3320 will run you out of the cab. What I understand the 3520 is the same engine with a blower or turbocharger. The 3720 is a different engine. Wonder if the block is the same?

 

[minimax]

So much for the hour idea, I was think something went wrong a so many hours but it does not look like that I have 200 hr and have heat still.I wonder if the break in engine oil has some thing to do with the diff. oil than 15-40w oil because beak in oil much lighter oil like 5-30w????

 

[NoMo]

Something must be different in the engine water jacket on the 3720. My 3320 will run you out of the cab. What I understand the 3520 is the same engine with a blower or turbocharger. The 3720 is a different engine. Wonder if the block is the same?

Actually, the 3520 and 3720 have the same engine. It's just that the 3720 has an intercooler for the turbo whereas the 3520 does not. The 3320 engine is different.

I suspect Deere tested the cab heat, but did so with the tractor under heavy load... thinking "who would be out just putting around in the cold".