Poor cab heat

[radman1]

Check to make sure the control actually opens the valve all the way.

I too have a heater problem with my Kubota. You have to be careful to only just barely move the heat control off of the coldest setting or it will drive you out of the cab. They must have designed the thing for arctic use.

Pat

That was checked and is moving normally.

 

[radman1]

outlets are on the left side. Their is a plastic tee with a cap on it just below the right side of the cab on the return line which must be for bleeding the line.
View attachment 63951

Thanks for the picture. Thats how it should be. To the pump or to the block. Not to the lower radiator hose. Maybe a different water pump could solve the problem and reroute the return hose.

 

[CATMAN]

radman1, your 3720 is a 3 cylinder diesel. dwmaster's 4320 is a 4 cylinder diesel. This is apples and oranges! Thanks, dwmaster for the piece of information, I guess I should have look at your profile. radman1 you can't use dwmaster's photo for help. I have looked at both engines and their water pumps on JD Parts and there really isn't any common shapes/designs for the coolant hose ports. 3720 has a casting with water pump, t-stat housing and outlet to cylinder block all in one piece. 4320 has water pump separate, then it bolts to the front housing which in turn bolts to the engine block. A 4320's thermostat is barrel shaped and looks light it slides down a tube where the upper radiator hose attaches on the front housing itself. radman1, hopefully the JD factory will help out with a solution for your lack of cab heat. I have cured a 40 foot motorhome's front heater lack of heat complaint(engine at the rear) by ignoring CAT's installation guidelines for OEM manufacturers, and plumbed front motorhome's heater inlet to upper rear of cylinder head (Note: t-stat at front of cyl. head) and put heater core return hose directly into the suction side of the water pump(CAT water pump has a port available). This solved the problem. Basically, I achieved this by getting maximum pressure difference between the inlet and outlet while still considering a reasonable compromise for a location that I can capture the heat of the coolant and push it 40 feet forward and then 40 feet back(returning directly to water pump helped here) Just a little info.

 

[radman1]

radman1, your 3720 is a 3 cylinder diesel. dwmaster's 4320 is a 4 cylinder diesel. This is apples and oranges! Thanks, dwmaster for the piece of information, I guess I should have look at your profile. radman1 you can't use dwmaster's photo for help. I have looked at both engines and their water pumps on JD Parts and there really isn't any common shapes/designs for the coolant hose ports. 3720 has a casting with water pump, t-stat housing and outlet to cylinder block all in one piece. 4320 has water pump separate, then it bolts to the front housing which in turn bolts to the engine block. A 4320's thermostat is barrel shaped and looks light it slides down a tube where the upper radiator hose attaches on the front housing itself. radman1, hopefully the JD factory will help out with a solution for your lack of cab heat. I have cured a 40 foot motorhome's front heater lack of heat complaint(engine at the rear) by ignoring CAT's installation guidelines for OEM manufacturers, and plumbed front motorhome's heater inlet to upper rear of cylinder head (Note: t-stat at front of cyl. head) and put heater core return hose directly into the suction side of the water pump(CAT water pump has a port available). This solved the problem. Basically, I achieved this by getting maximum pressure difference between the inlet and outlet while still considering a reasonable compromise for a location that I can capture the heat of the coolant and push it 40 feet forward and then 40 feet back(returning directly to water pump helped here) Just a little info.

Yes, I agree the designs are different, but the concept of dwmaster's water pump with the return to the pump is more ideal than the return hose to the lower radiator hose. The return heater hose on my 3720 should be of the same design as the 4000 twenty series cabs. The ideal solution would be to have a different water pump designed for the 3000 twenty series cabs and plumbed directly to the water pump or have it return directly into the block. According to my service manager, JD knows that there is a problem but doesn't really have a solution. The bizarre part to me is why others on TBN don't seem to have the problem but my dealer has 3 known 3000 twenty cab tractors and all have this problem. Service guy told me they just ordered another cab 3720 for a customer and it will be interesting to know if this one also has the same issue. That customer had heard of a heating problem from another dealer but ordered it anyway. (My dealer has only sold 3 3000 twenty series with cabs and just ordered this last one. All were sold in the past summer and fall.)

 

[mike311]

radman, you stated your dealer knows of 3 3x20 series cab heaters not working properly. Did your dealer install block heaters in these 3 tractors as well as yours? I'm not sure what type of heater goes in your tractor but if it is installed in the coolant "jacket" of the engine, there was a possibility that air got into your coolant system during installation of the block heater. If you have air trapped in your heater core, it is not going to work its way out due to the location of it. Again, my brothers tractor had a dealer installed block heater and his problems were identical to yours. mike

 

[minimax]

I argee that some thing is fishie here because no one else on here has a prob.,but your dealer has had three???

minimax

 

[CATMAN]

If your dealer was interested in verifying that the heater core is bled and no air is entering system and also could monitor the flow of coolant, then I suggest the get some clear plastic tubing(sold at Lowes and probably Home Depot) of the correct size and some smooth barb unions of the correct inside diameter(5/8" or 3/4") and install them at the water pump heater hose inlet and outlets.(This would only be 6-12" worth of additional hose for "test only" purpose at each location) Also install them at the heater core up at the cab(under the roof). At the same time as this, They should visually inspect that the cab heater valve control is totally open INTERNALLY when the cab selector is rotated. They could also fill the cooling system as much as possible at the radiator, then pull the hose at the heater core(under the roof) and use a small funnel to add the rest of the coolant to top it off. This should achieve 99-100% coolant fill. Reattach heater hoses with 6-12" clear plastic "test hose splices" onto the heater core. (These hoses would only be additional lenght of hose for test only). DON'T CUT FACTORY HOSES. The reason that dealers are stubborn to go to this extra effort and expense, is because WARRANTY won't pay for this under NORMAL channels. The dealers has to get the JD district representative involved first, explain the situation, explain what procedure they want to try and test for , and then get a "GOODWILL or POLICY" authorization number. This allows the dealer to get paid for his unusual testing time/labor and parts. This requires more time and paperwork at the dealers' end. I feel with 3 tractors in their area with the same complaint and the factory doesn't really seem to help much or "it is currently under investigation" reply, someone needs to go the extra effort. As a customer, I suggest you complain directly to John Deere about the problem (not the dealer), then ask for the district reps name and work phone number and explain the problem. Call back two to three days later to follow up with the district rep. (be polite but stand your ground). The old saying is that "The squeaking wheel gets the most grease". Sometimes one has to play the game this way to push the factory into action. This action should never be the first step, but a lot of customers don't know there are higher channels of management when it comes to Warranty Issues and Operational complaints, AFTER you have given your dealer two or three attempts at the same problem. Don't ruin your relationship with the dealer, you are just trying to get the factory to open up their wallet to hunt down a solution and sometimes those solutions are found at the dealer level(by mechanics) and sometimes at the engineering level. After a solution is found, then hopefully the engineers write a "Service letter" or "Tech bulletin" to explain that complaint/solution to all the other dealers in North America/World. This is just a little insight to the dealer/district rep/factory=engineering groups/warranty groups that have their own accounts($$$$) to protect and sometimes it gets to be a game of "Pass the Buck". This is where the customer has more POWER than the dealer when it comes to complaining to the right areas or ALL areas. Hope any of this info helps your cause.

 

[turbo36]

I argee that some thing is fishie here because no one else on here has a prob.,but your dealer has had three???

minimax

I posted awhile back that my new 3720 was working just fine when tested it at 45 degrees, well, this weekend it got down to 30 and tried it again but this time I got different results! At 1500 rpm the temp Gage barley moved and the temperature of the air coming out of the heater ducts was 70 degreesit looks like I have the same condition. I plan to call my dealer tomorrow.

 

[radman1]

Turbo36
I'm sorry you seem to be having the same problem. Now I feel it's not just me. Let me know how it turns out. Have them check the engine temp after running 15 minutes and again after clamping of the return heater hose. My guess they will see a dramatic increase in engine temp only to have it drop after unclamping the hose.

 

[radman1]

Catman
This problem is more than air in the heater core. The heater core will put out 120F heat, if the engine gets hot. The problem is the engine won't heat up on a cool day unless under load. Both the feed and return heater hose temp follow the same as the engine temp. Cold engine = cold hoses. Hot engine = hot hoses. If there was air in the heater core, the temp in the hoses and engine should still get hot, while the heater blows cooler air which is not the case.
The dealership has really been good throughout this issue and they agree this is not right. (Although they keep selling cab tractors.) Next line of action may involve going up the food chain to area rep, JD etc.