Poor cab heat

[WhyNot]

Hope you guys don't mind me jumping in so late but I agree with dwmaster that JD might have found the cause. Here is what i think is going on (just from what I skimmed through in this thread) Your tractor is running cool because it was designed to be ran under the harshest conditions ie. heat, dust, wide open for hours on end etc. Using it to mow the pasture or push snow and other chores does not put enough of a load on the engine to heat it up a lot. So now the water passing through the heater core is already cooler but not so cool that you would notice there was a problem with the temp of the air coming out of the vents. Now add the fact that the already cooler air is drawing in cold air after the heater core because the roof is not sealed correctly and you will notice a big difference. If it were me I would just as a trial put some tape where the roof seal is and see what happens. If the air is hot enough then take it back to the dealer and tell them to replace the seals.

 

[BTDT]

I still think it is related to engine not getting hot enough. Is the fan the only thing run off of the fan belt? Loosen belt so it doesn't cool as effectively as it would with a tight belt. Take it out and work it, see if temp comes up, comes up quicker, no change. If it was mine, I would even be tempted to turn fan around (so it would blow through radiator) to decrease air moving over block, and see if that made a difference. If A(you get water hot, and B(water is circulating through heater, then C(cab should heat up.

 

[radman1]

I was just about ready to reroute the heater hose but chickened out. I called another dealer who will look at it on monday. Talked to their service guy who thought it should be an easy fix. I told him to talk to the regional rep, Loren, who knows this tractor all to well.

 

[radman1]

Hope you guys don't mind me jumping in so late but I agree with dwmaster that JD might have found the cause. Here is what i think is going on (just from what I skimmed through in this thread) Your tractor is running cool because it was designed to be ran under the harshest conditions ie. heat, dust, wide open for hours on end etc. Using it to mow the pasture or push snow and other chores does not put enough of a load on the engine to heat it up a lot. So now the water passing through the heater core is already cooler but not so cool that you would notice there was a problem with the temp of the air coming out of the vents. Now add the fact that the already cooler air is drawing in cold air after the heater core because the roof is not sealed correctly and you will notice a big difference. If it were me I would just as a trial put some tape where the roof seal is and see what happens. If the air is hot enough then take it back to the dealer and tell them to replace the seals.

I see where your coming from, but the engine just doesn't get hot unless it is under moderate load. Then the engine gets hot, and I have all the hot air I want coming out of the heater. It is difficult to imagine that there is so much air movement over the heater core, that it can keep the engine from heating up.

 

[dirtworksequip]

radman, let me see if I understand your problem correctly. You say that you are not getting heat, but you also state that under moderate load it throws more heat than you need. I must be missing something here. I have a 3520 /cab,if its just sitting there doing nothing, idleing I would not expect to get any heat from the heater. Its just like any other piece of heavy equipment. If its not under some load.......no heat. Caterpillar 777 off road trucks are an example. Over $1,000,000 new. No load...........no heat. I guess I just don't understand when it is that you think you should be getting heat and are not.

Simply sitting there with the engine reved while better than just idleing still isn't putting the engine under load.

Please fill me in so I can better understand what the problem might be. I've followed your thread from the begining.

 

[gemini5362]

radman, let me see if I understand your problem correctly. You say that you are not getting heat, but you also state that under moderate load it throws more heat than you need. I must be missing something here. I have a 3520 /cab,if its just sitting there doing nothing, idleing I would not expect to get any heat from the heater. Its just like any other piece of heavy equipment. If its not under some load.......no heat. Caterpillar 777 off road trucks are an example. Over $1,000,000 new. No load...........no heat. I guess I just don't understand when it is that you think you should be getting heat and are not.

Simply sitting there with the engine reved while better than just idleing still isn't putting the engine under load.

Please fill me in so I can better understand what the problem might be. I've followed your thread from the begining.

Theoretically because it is an internal combustion engine it produces heat. My understanding of the purpose of a thermostat is to allow the engine to heat up to a predetermined temperature before it starts doing any cooling. So whether it is working hard or just idleing the engine should heat up to the operating temperature of the thermostat.

 

[radman1]

radman, let me see if I understand your problem correctly. You say that you are not getting heat, but you also state that under moderate load it throws more heat than you need. I must be missing something here. I have a 3520 /cab,if its just sitting there doing nothing, idleing I would not expect to get any heat from the heater. Its just like any other piece of heavy equipment. If its not under some load.......no heat. Caterpillar 777 off road trucks are an example. Over $1,000,000 new. No load...........no heat. I guess I just don't understand when it is that you think you should be getting heat and are not.

Simply sitting there with the engine reved while better than just idleing still isn't putting the engine under load.

Please fill me in so I can better understand what the problem might be. I've followed your thread from the begining.

The heater should be like that in a car. Even at idle a car's engine will heat up and thus the heater will blow out warm air given adequate time. My tractor and yours should behave no differently. It is a combustion engine, it makes lots of heat. Even at idle, the exhaust heat at the turbo on a cold day is 212F. For some reason, the circulating water returning from the cab cools the engine so much, the engine cannot make operating temp. To say that my idling block temp at the water pump should run at 97F (ambient temp was about 40) is crazy. It also is not good for the engine or efficient fuel combustion to run at that low temp. If I clamp the return heater hose off so there is no flow through the cab, the tractor will heat up to full operating temp in about 12 minutes at idle. Even JD corp says the tractor was tested at -16F with tractor idling and the operator was comfortable in a tee-shirt. 2 dealers also agree that is not how it should perform. Even if I get the engine up to operating temp, it will cool off in about 15 minutes at an idle and blow cool cab air out the heater. Does your car's heater stop putting out heat if you quite driving and let it sit while idling? The answer is NO.
This is a problem at 40F. What will it be like at 0? -15F? I may not have any cab heat even under load at very cold temps. Even with the heater and fan shut off, I cannot get the engine to warm up at an idle. Remember water is always circulating through the cab/hoses even with the heater shut off which is why clamping the hose will get the engine temp hot.

Our 2 cab ag tractors will heat up at idle and this tractor should too.
If your 3520 cab heater doesn't blow warm/hot air after a reasonable length of warm up at an idle, then you also have a problem.

 

[dirtworksequip]

I'll check it tomorrow. I'll get the cab comfortable and then let it sit and idle to see if the cab heat cools. So, far I've been satisfied with the heating system. Most of the time I have to turn it all the way down. Gets too warm in the cab.

 

[radman1]

I'll check it tomorrow. I'll get the cab comfortable and then let it sit and idle to see if the cab heat cools. So, far I've been satisfied with the heating system. Most of the time I have to turn it all the way down. Gets too warm in the cab.

Will your tractor/cab heat up if you start it, then run at an idle if the outside temp is <40? Do you live where it gets cold?

 

[dirtworksequip]

I'll check it in the morning at idle. Air temp should be around 26 to 30 degrees. I'll start it...... then check to see if I have heat at 1 min intervals.