4720 Cab Tractor Slow to Warm UP

[Spudland_Dave]

From my point of view here a few hundred miles away I'd say its probably not the t-stat either...A busted t-stat USUSALLY shows up in summer/warm months, not winter...Key word is USUALLY.
Without going out to check my tractor for sure...but I think that the T-Stat does not control the temp of the air in the heater core....you got water circulating there no matter the temp of the water...just like in a car...so I'd think you're cooling the water as fast as your generating the heat. I've gotten to the habit of shutting the fan off till I see some heat on the gauge..yesterday I had heat in NO time at all.. Once the gauge starts moving I turn on the fan and I got a warm cab in no time. Actually USING the tractor makes a difference in how fast it warms up too.

 

[TCowner]

Radman, thanks. I remembered your story from a couple of years ago. When I purchased the 4720 in January the factory CD player was on back order so I had them deliver the tractor with the am-fm radio. When the cd player arrived and I realized they had to remove the cab roof to get access believe me, the problem with the roof seal was a concern. I actually mentioned to the service rep that some other cab owners had experienced problems with the roof sealing. The roof went back on with no problems and I had great heat all winter long.

This is why I think I know what I'm talking about. Great heat last January at temps below zero and now average heat at best at temps of 20 above.

My brother and I are going to the woods this afternoon to cut wood. I will be using the grapple and might have to plow through some snow so I plan on giving the tractor a good workout. I had told the service rep that I would report back tomorrow but unless somehow the cab "heals" itself today I will begin pushing the the idea of starting with the roof seal issue. Thanks again.

 

[turbo36]

I would have them recheck the seal in the air box over the cab. I had a problem with my JD 3720 cab. Yes, it could be the thermostat but it would seem a bit unlikely in a tractor that new. I went through a new thermostat with higher setting than standard and multiple trips to 2 different dealers, talks with the area JD rep, JD technical help etc. Finally, a leak was discovered in the air box. I didn't start noticing the problem until the temps were in the 30's. An easy way to check if it is the air box, is to clamp the water hose leading to the cab on a cold day. If the engine heats up quickly with the hose clamped but cools again after removing the clamp, you have a problem with an air box leak. A leak pulls too much cold air into the air box and cools the air out of the heater as well as cooling the entire tractor water system. Do a search on "Poor cab heat" to hear the entire story.

The dealer installing a new radio, also makes the possibility of a leak very high IMHO.

I had the same deal with my 3720 Cab, after they fixed the seal the engine heat came up in the normal fashion.

 

[Kyle_in_Tex]

I believe that if the thermostat was stuck open, with all the cooling capacity, it would never get warm enough in 20ｰ weather to keep you comfortable. Solar radiant warming is a factor on sunny days.

Good luck in figuring it out.

 

[nmu98]

It was 13 degrees this morning. It took my tractor about 5 minutes of running to start to push warm air. After 8 it was OK to put it to max and it blew warm air. After 12 minutes I had to turn the heat down as it was blowing hot air. This was simply clearing ice and snow from the driveway.

 

[4720 OWNER]

Start tractor, follow manual and put throttle forward about 1/2 ( about 1300 rpm), let sit for 5 min while the diesel fumes dissapate, turn fan on low and start doing whatever. At 10 min the hat comes off, at 15 the gloves come off, at 20 starting to wonder why i still have a coat on. At 30plus down to short sleeves and short pants and looking for palm trees and tanning butter start turning temp down and fan on minimum to keep the cab from fogging over!!

Oh and by the way, John Deere boots work well in JD tractors, seem to just fit the pedals correctly and the proper amount of traction.

 

[TCowner]

4720 Owner, Where was the needle on your temperature gauge when the tractor was warmed up? With a piece of cardboard blocking a good portion of the airflow through the radiator the temp gauge now goes to the middle or just slightly above like it did since it was new. I had tried the cardboard trick before but must not have used the tractor long enough. Once the temp gauge approaches the middle of the range I get plenty of heat so it seems as though the cab roof seal is OK.

When I remove the cardboard the temp gauge slowly drops back and I have less heat. My dealer rep thinks it has to be a thermostat issue. As long as the cardboard trick is working I am going to wait until after January 1 as I have some time off the next few weeks and have some firewood work to do and don't want to be be without a tractor. We also have some snow predicted over the next several days.

 

[Karl2]

Just curious, for those of you with the 4000 cab tractors where does your temp guage run say after about 15 minutes? Under normal conditions mine runs just a tad over the half way point on the guage. It was well under that last night and I was operating for about 45 minutes so I'm thinking its a thermostat issue.

My coolant gauge usually reaches the half mark regardless of outside temp but how fast it gets there depends on temperature, but I wouldn't count on great accuracy from these gauges (see thread about fuel gauge). As for cab heat it takes a long time to warm up when tractor is idle after start (in winter tractor needs to warm up for a good 15-20 minutes otherwise it's sluggish) but gets very warm pretty quickly with machine at work. That's when I remove my jacket and work in a t-shirt even when it's 20 below out. I am told heat up time is normal for a tractor that sleeps out in the cold.