DK50HST Running Hot

[acme97]

Today, I was doing some light work around the place - moving brush, stumps to a burn pile when I noticed the tractor was running close to red. I wasn't running hard, maybe around 1500 rpm, outside temp was about 80, had AC on. I stopped the tractor and let it cool off. Checked the screens (had a little) build up, cleaned it off and went back to work. Probably 15 minutes later, was hot again. So let cool down and moved to parking area for day. Any ideas why it would be heating so fast? Didn't see any fluids leaking etc.

 

[DieselMonk]

fan belt lose?

 

[acme97]

fan belt lose?

No, not that I noticed. I'll have to double check to make sure. I plan on checking the coolant also, but with only 41 hrs on it, I figured that would be to specs.

 

[ritcheyvs]

It may be cliche, but if you have coolant, the radiator isn't blocked, and the fan and pump are turning; thermostat is about all that's left.

 

[MotorSeven]

Make sure the pre-screen(s)-there are two- on the radiator are clean. Then look between the oil cooler and the radiator for a mouse house..... you have to really contort yourself to check that. I chased a mild overheat thing for a couple of days before I found the nest because you can't see that area very easily.

 

[acme97]

Make sure the pre-screen(s)-there are two- on the radiator are clean. Then look between the oil cooler and the radiator for a mouse house..... you have to really contort yourself to check that. I chased a mild overheat thing for a couple of days before I found the nest because you can't see that area very easily.

Good point, I did clean the screens, but didn't see a mouse nest so to speak. I think I'll take a closer look and use the compressor to blow things out, or the shop vac.

 

[Coyote machine]

The thermostat could easily be a problem if it's stuck closed and doesn't open on temp being reached. Here's what I'd do. Before starting it, AFTER checking radiator fluid level, and expansion tank fluid level run it lightly up to normal operating temp. See if it comes to normal range on gauge. Keep the AC off for now while diagnosing. Check to see if there is any fluid in the expansion tank after running it up to 'normal' temp. If whatever fluid was in the ex tank is now gone the radiator has sucked it up. Carefully, with a rag on the radiator cap and with gloves on your hands turn the rad cap 1/2 turn and see if there is any pressure or fluid wanting to escape from beneath the cap. If so, then let her cool to ambient temp and then remove the cap and recheck fluid level. Then you can try running it with the radiator cap off at idle and see if there is noticeable flow of coolant in the radiator. If not then the t-stat is probably not opening, and replacing it would be a good place to start. Once you remove the stat you can drop it in 180+ degree water and see if it opens or stays shut.
There are two other things that might be wrong- the gauge or its temp sender could be reading wrong, but considering the 80 degree ambient temp and using the AC I suspect not on these items.
Try to assume nothing and if you can't find the solution DO NOT use the tractor until you do find the cause. It is unlikely with the low hours that it's a head gasket, but anything can happen. Some 50HP Kioti's had a head gasket problem- but I can't recall which particular series/model at the moment. Maybe someone else can chime in on this....

 

[grsthegreat]

i second the cleaning of the radiator fins and front grills, screens.

I have seen this same thing happen to my tractors.... especially after mowing the fields.

caution needs to prevail so you dont damage fins of radiator.

 

[acme97]

Good advice on all the options. Unfortunately it'll be a few weeks before I'm back to the place. Now working out of Jacksonville! If you guys think of any more things just yell them out. K

 

[LastSTRAW]

It shouldn't happen on a new tractor but check your oil just in case. My neighbour's 4600 was overheating last year. He couldn't find a coolant leak until he checked the oil and found lots of it there. Had to replace to head gasket at $$$$$.

 

[acme97]

Update: Cleaned screen, blew out under hood, checked radiator (full), and reservoir. Reservoir was very low, so added more coolant. Fired it up and worked for hour plus and everything just fine. Thanks for all the tips. Always check the basics first.

 

[Mark Headley]

It shouldn't happen on a new tractor but check your oil just in case. My neighbour's 4600 was overheating last year. He couldn't find a coolant leak until he checked the oil and found lots of it there. Had to replace to head gasket at $$$$$.

I wouldn't personally throw a bunch of head gasket bucks in a motor that had water in the oil for however long- wipes out lubrication and the lower end can easily, prematurely take a dump. A motor that was passing coolant out the exhaust is one thing but once there's water in oil all bets are off.

 

[LastSTRAW]

It was a risk but it was his only tractor and he needed it for all his chores. It has been about 10 months since the repair. So far so good.