3720 JD cab with poor heat

[capp0021]

I recently received a new 3720 cab and at first the heat didn't work at all. I had to go out of town and the dealer came and did something but I don't know what as I was out of town and now with Christmas... Anyway, it works now but not well. It has been cold here, it was maybe 5 degrees the day I drove it around to test it. There was not much snow so I couldn't really work it other than drive down the street. As it is now, if you sat in the cab and it idled you would freeze to death. When driving it I got fair heat but not what I feel it should put out. The heat gauge came up over half an inch...as warm as my old 3720 without a cab would ever run even when working fairly hard. I sure wish they had numbers on the gauges. Anyone have any tips or ideas? I tried a cardboard in front of the radiator and if it helped it was only slightly.... I have found no posts from anyone having any similar issues.

I don't know if a different thermostat or hotter one would help? Maybe the fan could be removed? I really wish it would just work right...

Any help or ideas would be great, thanks!

Pat

 

[kuboman]

I would wonder of the valve that controls the flow of coolant to the heater core is not opening very much. Either that or the heater is really undersized.
How old is the machine?

 

[capp0021]

That's the thing....it's 5 days old! I may go to the dealer and go drive one around on the lot to compare to mine... They say they don't put out much heat unless you're working them, which is not much of an answer or solution.

 

[mjncad]

I'd bet the cab roof seal is damaged. I hear that is a common problem on cabbed Deere's.

 

[capp0021]

Yeah, I was just reading about that now...I couldn't find a pertinent post until I started mine! I did have a radio installed, but you would sure think they would know about this issue... Like I said earlier, I had NO heat at the start, so I wonder if they have been in the roof twice now...

I'm going to go talk to the dealer tomorrow...or today I guess, its pretty late here.

I don't know if anyone reading this has read the older post (from 2005-7), but I may be starting to get paranoid now, as this new tractor smokes and smells stronger than my 2005 3720 (without cab - that's why I got a new one!) also.

anyway, thanks - we 'll have to see and I will post results for the next guy with this issue.

 

[greg_g]

Mine had poor heat, which was fixed by a tech who'd apparently never worked on a 3720 cab before. It was indeed the heater core valve not opening fully, an issue remedied by a simple adjustment of the cable between the cab and the core. But he apparently thought he could remove the cab roof by himself. Either that, or he over-estimated his ability to lift the roof by himself. That mistake damaged the roof seal, and of course they didn't have a replacement in stock. The damaged areas were "fixed" with auto store weather seal. I'd already had previous issues with the selling dealer, and this was just one too many. I shifted my warranty work to another dealership.

//greg//

 

[Cigar Face]

Here's a recent thread about your issue and the fix
http://www.tractorbynet.com/forums/...ng/265483-obtaining-heat-inside-3320-cab.html

 

[sixdogs]

On things like this I have learned to start with the easiest answer first and work up from there so my guess is on the flow valve not fully opening. Remember that tractors take a long time to warm up when it's cold old and even a half hour at low air temps would likely barely do it. Low heat until things warm up.

 

[kuboman]

You will have a temp knob in the cab which adjusts the heat output by opening or closing a valve. This may be out of adjustment. Also on a lot of machines there are shut off valves in the heater lines at the engine. One or more of these may be mostly closed. Just some more options to check.

 

[sunnyside360]

I have a 2007 3720 which I bought new March 2007. The heater was anemic when new similar to yours. Turned out the roof seal was damaged and leaking cold outside air into the roof chamber. Heater worked fine after dealer replaced the seal. The roof had to be removed at the dealership to install the radio prior to delivery so the seal may have been damaged then but not sure. I found the problem by removing the roof to check items described by other posters above. Roof install/removal is definitely a 2 person job otherwise the seal is likely going to be damaged. Other popular causes of weak heat in the 3x20/4x20 cabs has been air trapped in system and heat valve adjustment as noted above. Your dealer should fix this issue under warranty.

 

[capp0021]

Ok, so I tested the cab roof seal with a punk (to light fireworks - I couldn't find a cigar!) inside the garage...couldn't find any leaks. Something funny going on with airflow around the right front turn signal/work light but it isn't anything major. The dealer said they bled the system after my first complaint of NO HEAT WHATSOEVER.... You'd think they would have known to do that after installing the block heater.

So today it was single digits above...here in Fargo, ND....anyway, blew some snow, just an inch or so but the heat was ok, not great but ok. I even had to turn it down some, LOL. One thing I think makes a huge difference is the sun was out/no clouds. I think If I would have done it at night it wouldn't have felt so warm.

Anyway, I am going to try it for a while and see what happens. There is a 3520 on dealer's lot that I will warm up and tool around the lot in if I think the heat still isn't up to par(to compare to). I should say too that the dealer said they didn't take the roof off, the radio was installed at the factory. And for those who mentioned a valve just outside/below the cab on the heater hose...there isn't one that I can see anywhere. So, there is still a possibility the knob cable is out of adjustment...like I said, I will try it for a while and see what happens. And I should reiterate that I do have a solid piece of cardboard in front of the radiator...I'd say it helps just a tiny bit....

Got my first ding in my 59 front mount blower today, I suppose there will be more to follow! Hit a curb...anyway, today I bought another set of skid shoes and installed them so now I have shoes inside the blower and outside as well...I wanted them outside to help me stay away from curbs to preserve my yellow paint and inside because I have 5' (commercial zoned) sidewalks and I think it helps to have the ones turned in as JD intended. Those things are over 47 bucks each!!! I also got a couple elbows for the hoses that run the spout...they were straight and when you turned hard to the right the tires would rub. If I had forgot about it and turned hard to the right and went over a bump so as to raise the right side of front axle I swear I would have ripped the hose out. At least the dealer gave them to me no charge - said it shouldnt have left the lot like that. The specs do call for straight couplers but I suppose the 59 is used on multiple tractors - some may not have an issue. One other thing that got on my nerves was they didn't remember to tighten the lock nut on the top link and it turned and sometime when I raised the blower I broke off the (storage?) stem....sloppy...anyway it didnt do much but a little scratch on the grill guard and they ordered a new one (after I dropped the broken one on my salesman's desk). It is things like this and them not bleeding the system after install of block heater that makes you second - guess what they say and do...

All right, I have already written too much...Had to vent a little. Thank you to all who responded, I certainly appreciate you sharing your experience.

 

[Cigar Face]

Well as you already know, deisels do like a blanket in front of the radiator. Alll of my companies peterbillts have them up front. Most of our new cat dozers run luke warm and not blazing hot like a gasoline car. Especially since your in fargo, you are probably better off with a blanket or some sort of sheild in front of the radiator. I think some guys arent taking in the fact the extreme temperatures you have up there. Thats an extreme amount of coldness for these small deisel engines and to get the proper heat without other measures is unreal. I think your tractor is most likely working 100 percent after thinking about it and reading your last post. Thats just me though and you know what they say about opinions hahah

 

[Brimstone10x]

I have ran into no heat on acouple of these tractors and found that the heater hose was squashed between the black inner roof and the rops from the factory. so after the valve is ruled out make sure both hoses get hot . good luck

 

[jdboy4410]

it is true,it takes time for a diesel to produce heat,they run cold till they start working,but if your temp gauge is in the normal operating range,it should produce hot water for the heater core,those hoses should be nice and hot going in and out,the control valve out of adjustment is the right direction to look first,the hot water needs to flow in and out,if there is air trapped,it will create an issue as well.i use a tool called an air lift,which when the cooling system is empty,you attach it,apply shop air,and it creates a vacuum within the cooling system,once drawn down,connect the coolant supply hose down in a bucket full of coolant,and it will suck it into the cooling system with no chance of an air pocket to form.it fills the system fast too,usually within 30-45 seconds.i would think you should see at least 100-120 degree temps coming out of the air ducts when the system works properly.i don't know JD's specs on it nor do I know how big of a core they are using.at that temp,it should warm the cab easily.if the a/c makes the cab good and cold,the heat should make it good and hot,,,,

 

[BlackRaptor]

I was pushing snow last Thursday during the big snow storm here in MN is was after dark and 3f still air temp is what the pickup said when i moved it out of the driveway. I noticed that if i idled the tractor at its normal 1000-1100rpm bottom of the throttle it would lose heat pretty quick i found if i needed to idle it to keep it at least at 1500rpm's just to maintain engine temp and when moving it around i ran it in A range 2000 RPM. At 2000 RPM's the heat was kicking out HOT HOT air and i was in a t-shirt pushing snow listening to the radio drinking coffee which was amazing by the way. I also drove it 3 miles into town to push the parents out than 3 miles back never once did i have problems with it not keeping the cab hot if anything even in a t-shirt with it being 3f outside not counting wind chill i was overly hot and had to turn it down. I also have no blanket or anything on the grill and it heated up just fine.
I does take a VERY long time to get upto operating temp but thats a normal diesel in the winter. i normally start it let it idle a few min than throttle it to 1500 rpm let it idle at that till the temp gauge shows heat before i even think about working it. I've always been super picky about never working a cold diesel engine. So if yours wont give you heat i would question something is wrong. Should not need a blanket.

 

[greg_g]

I had a block heater installed. Not so much for the engine, but as a pre-heater for the cab. The direct injection engine doesn't need much help getting started. But it's nice to have the coolant already partially warmed when air starts coming out of those vents.

//greg//

 

[sixdogs]

The block heater is a great idea I forgot about. The ones that connect to a heater hose line and have a little pump built in in to circulate the coolant are the only ones to use.They really speed along the warm-up process since the circulated coolant fully warms the engine.

 

[greg_g]

The ones that connect to a heater hose line and have a little pump built in in to circulate the coolant are the only ones to use.

That's not a block heater, it's a tank-type heater. And I bought one myself (900w), under the very same misconception. Bought a second one (1500w) thinking there was something wrong with the first. Turns out neither actually had a pump inside, they relied strictly on the "heat rises" principle (conduction). And the length of heater hose that rises up the front of the cab frame is just too long to "conduct" as far as the heater core. Put both tank heaters in a yard sale, and went with a 1000w block heater. I don't have hot water in the hoses, but I do have a block full of warm water. So when I start the engine, the water pump physically circulates that water (convection) in the direction of the heater core.

That's not to say there are not higher end tank-type heaters with internal pumps. But the standard fare sold at auto parts stores - doesn't. At least not the two I bought.

//greg//

 

[sixdogs]

OK, that works but I have had KAATS brand heater hose type heater that sure made a sound like they had a pump in them. I could hear a pulsing "whoosh" type sound that sure sounded like something was pumping. Now that you mention it maybe I do remember the word "recirculating" rather than "pumping" on the package. It's been a while.

The entire block would be warm, or relatively warm, and I lived a climate that very often saw 25 below. My plow truck was left in the barn and I plugged it in the night before a storm and could hear that repeated whooshing sound when I first plugged it in as well as in the morning.I guess it could be a recirculating sound. Whatever it was, the coolant was warm when I got in and it sartted like summer. Note, remember to leave heater cables on "high" to allow coolant to circulate.

A block heater is surely the best choice but I coudn't acess the block plug to install it. Plus, for me, the KATS heater worked.

 

[capp0021]

Today I was changing out the 59 sb spout couplers from straight to 45's. I had put on 90's but one line was just tighter than I'd like. The 45's work and look great. No tire interference now.

Anyway, it was in the teens and sunny so there was a lot of heat from that...when it was sitting idling it was actually colder with the heat on than to just turn off the fan. Point is, there was just a thin layer of snow but you know, nice new green tractor, gotta use it some... I had to do a lot of turning and back and forth but the heat got nice and warm. Other thing I did was to do a better job with the cardboard. I.e. - I cut it to fit perfectly over the radiator and used some dense foam to make sure it is pressed tight so no air through the radiator.

I am thinking it works as good as it will work. I would love to take the roof off and check the cables to the knobs but it would be a cold pain in the ***** (do these forums kick out foul language?) and I don't want to mess up the seal.

Thanks to all,

Pat