Chronic Kioti DK40 SE Overheating - Seeking Advice on Removing Thermostat

[Alan46]

Alan,

Ummmm, okay, I'll confess. Taking off the bushhog, or the FEL, that is easy I know for most people, but it is a real adventure for me. I won't if I can possibly avoid it. I do have neighbors who would help me so I'll keep your suggestion in mind. Thanks!

I didn’t mean to remove anything just drive around without putting any strain on the motor!

 

[Rhino35]

I had the same problem on a 33 hp tractor when running the bush hog temp would creep up slowly started after 35 min to an hour to reach 220 I stopped the tractor at 230.

I finally gave up when I could not find the cause, so my solution was go to the junk yard and buy a 12VDC auto fan with a shroud (I think it came off and older Volvo). I mounted it in front of the radiator blowing through the radiator.
I wired it from the battery to a switch and when the temp started to creep up to 190 I switched on the fan
PROBLEM Solved I could run all day.

EDIT: I had been running it with the hood off so I could run it longer before shutting down and just left it off since the fan wouldn't fit with the hood mounted.

When mine started its creep towards overheating I'd leave the hood up while bush hogging. This is admitting to stupidity, but...I'd engage the hydrostatic "go" pedal with the cruise control magnet and stand up and to the side, steering with one hand, so I could see the next row to cut.

 

[garry1p]

Well I hope you find the problem.
I did everything suggested for you so far.
Took radiator to repair shop rodded, cleaned and pressure tested.
replaced the radiator cap
had good flow with the thermostat open
no air bubbles in the radiator (cking for bad head gasket)
added an overflow bottle
etc,etc,etc
I never replace the gauge or the sending unit

With the electric fan I could run all day and not overheat so I figured the gauge and sending unit was OK

You are right, not a good idea to stand and drive a tractor.
I ran mine for 3 years with no hood never a problem (it was parked inside).

 

[Rhino35]

I appreciate the suggestion to take off the hood. I keep the tractor parked inside.

I bush hog most of my hillsides once a year in the fall. I do it then because the ground isn't wet and soft as it is in spring. The vegetation can get real thick and high and without a hood a lot of "stuff" would get dragged near, and probably into, the engine compartment. It's sturdy inside so I may give this a try if all else fails.

 

[Slowpoke Slim]

OP,

I can't see how taking off the hood would do anything for you at all. Honestly, it makes no sense.

The only reason Gary did it was because his added electric fan wouldn't clear the hood.

 

[Slowpoke Slim]

Ok, after slogging through your posts, I think the only (rather obvious thing) that I never saw mentioned was your radiator cap.

Has it ever been changed? Has it ever been tested? They can be pressure tested. So can your entire coolant system.

What you have described, with all other things being eliminated (at least it sounds like all other things have been checked), sounds like chronic low pressure, or open no pressure of the coolant system. If your radiator (whole coolant system actually) isn't building pressure, it will ALWAYS overheat. Even when it's cool outside. Modern closed system coolant systems have to build pressure to work properly.

My advice would be to have the cap pressure tested. If that comes back good, then have the coolant system pressure tested. Don't know what auto parts stores are in your area, but there are several that will either loan or rent out things like pressure testers. Many will also pressure test your cap if you take it in there.

If it's not one or the other of those issues, then your radiator is not flowing coolant across all it's cores.

All this is first assuming things like your fan and fan shroud are good and in place (shroud).

 

[Slowpoke Slim]

If you really want to try running it with no thermostat, then take your "old" thermostat and cut the center out of it and reinstall just the outer ring portion back in the housing. That will give you the same flow rate as a fully opened thermostat that's functioning normally.

 

[Slowpoke Slim]

My problem is...2013 Kioti DK40SE 41 HP tractor with 440 hours (which averages only 48 hours a year and is spot on my usage per year) that chronically overheats AFTER some period of use. 6 foot wide heavy duty Tarter Bushhog and OEM FEL, both I always leave attached because that is my 68 year old not very good with tools path of least resistance. The rear tires (Industrial type all around) are loaded with RimGuard, and for stability on hills I have one 4" wheel spacer on each side I purchased right away to increase the rear wheel's width. How long before the temperature gauge starts to slowly climb depends - but it will, and even in 60-70 degree cooler weather - and will even when it doesn't seem to be "working" hard hogging and driving up and/or across the hills (two wheel drive, flatter land, cutting 20 inch high grass). I could have bought this same model hydrostat tractor with 45 HP and looking back wonder if I should have (if it had a bigger radiator?) because I have suspicions my tractor could just be underpowered. Kioti tractors have heavy frames for sure.

Always garaged, very well-maintained by me after dealership did the comprehensive 50 hour new tractor service. I bush hog about 7 hilly acres 2 times a year (the really hilly parts usually once a year in October).

I have a nearly identical setup with my Branson. My engine hp is 37, but my pto hp is 32. Almost an exact duplicate of what you're running. Mine is also "heavy" (4200 lbs bare chassis) and my rear tires are also filled with Rimguard. All that to say, I am also running a 6' brush hog, and our summers regularly get to 90-95 degrees with humidity. The only time I have issues with getting hot is once my radiator and coolers get plugged with chaff from mowing. And I'm running a cabbed tractor with a/c. And when it's hot out, you better believe I have that a/c cranking.

Once I blow the chaff out of my radiator and coolers, the temp gauge drops right back to the normal range again. Sometimes I can go for hours, sometimes all day, sometimes I have to stop every "lap" I take on the field. It really depends on the field and how much chaff I'm kicking up on that job. Last job I did the field was very soggy wet so there was no chaff at all to contend with. I ran for 6 hours straight (well I did stop to replace one broken shear pin) with no overheating issues at all. Meant to add, this was a field with average weed/grass height of top of the hood, and a few areas where the weeds were 6 feet tall.

Point of all this ramble? I don't think you need to second guess your tractor choice, either size or hp rating. There's something else at play here.

 

[LittleBill21]

I will add this to this post, and I know some people might find these expensive. But the amount of stuff I can diagnose in seconds with a thermal camera is unbelievable, this can almost tell you in seconds where the issue is for most things.

Amazon.com

 

[Rhino35]

If you really want to try running it with no thermostat, then take your "old" thermostat and cut the center out of it and reinstall just the outer ring portion back in the housing. That will give you the same flow rate as a fully opened thermostat that's functioning normally.

This is a great suggestion!