Chronic Kioti DK40 SE Overheating - Seeking Advice on Removing Thermostat

[murphy1244]

Did you use the hose to flush out the cleaner that you applied? It's odd that so many people don't want to use a hose on their radiator because they think it will create mud, or the dust will build up from moisture, but nobody refuses to drive in the rain for that same reason.

It sounds like your fan belt is nice and tight.

Since you are still getting dirt out of your radiator, you really need to get the hose out and get it all cleaned out.

And maybe try some A/C coil cleaner.

 

[ruffdog]

I back blow my radiators every time I mow. There was a thread (kubota?) a few years ago that sounded like this one with overheating. The person finally removed his radiator and did a thorough washing/cleaning on his driveway. He had a picture of all the compacted chaff that came out from between the fins and it was A LOT. Being that the OP has been using a leaf blower I would bet that he has compacted fins. USE A LIGHT on every square inch of radiator to see if it is totally clear. Your engine will love you for it.

 

[Alan46]

I back blow my radiators every time I mow. There was a thread (kubota?) a few years ago that sounded like this one with overheating. The person finally removed his radiator and did a thorough washing/cleaning on his driveway. He had a picture of all the compacted chaff that came out from between the fins and it was A LOT. Being that the OP has been using a leaf blower I would bet that he has compacted fins. USE A LIGHT on every square inch of radiator to see if it is totally clear. Your engine will love you for it.

Great idea! It not to hard to do that!

 

[Gregster613]

Great idea! It not to hard to do that!View attachment 882449View attachment 882449

Like Alan46, I back blow mine almost every time I use the tractor for any length of time - my down flow exhaust kicks up a lot of dust that gets sucked into the radiator area and I want it ready to go whenever I need it!

 

[Alan46]

I just thought that I haven’t blown mine out for maybe 5 years or so, but I do remove the screens after each use of the BH and after using the chipper, temp gauge has never gotten past the suggested halfway point!

 

[Rhino35]

A thermostat is designed to keep the engine at a certain temp
to run efficently

willy

Yes, I understand this is a design feature. On some "thought level" of my "not all products are made right" realization of how even small cost margins can drive ultimate designs I have to wonder if the radiator in this Kioti tractor wound up just being too small. If it is too small then Kioti could be guilty of a design failure for challenging use conditions. If it is proper size then...well, my appeal to you and other experienced tractor owners to help me figure out what is going wrong. Which, I really do appreciate!

It's a tractor, and one of the main things tractors do is drag around mowing implements like bush hogs up and down hills in summer - powering them with the PTO. For any tractor to have such a narrow performance margin between staying at its ideal operating temperature and overheating from what, to my jaundiced eye, seems like fairly little accumulation of vegetative debris seems like a design mistake. I get it when the first screen gets clogged with the obvious stuff - that has to be removed - and that is easy with a portable left blower. But the finer stuff that gets in between the radiator fins - that shouldn't be a show-stopper after half an hour of bush hogging. I shouldn't have to quit and go back to the garage and used compressed air to blow that out, or rinse it out. So maybe the radiator really is too small.

Or, the thermostat isn't married up right in some sense. Maybe one opening at a lower temperature would do the trick to keep the engine cool, even if there is a fuel consumption cost to doing that?

Or, a six foot bush hog is too big. I should be using a five foot bush hog?

Or, my hills are steeper and the Kioti designers figured few customers would tax their cooling system like I must be doing with loaded tires, the FEL and the bush hog. Engineers stop short of creating "over-engineered" products on purpose because it costs more to do it "right". They can't upwards cost something a competitor doesn't similarly match in cost - or they won't sell. People are always cost conscious. The famous story of Henry Ford commissioning his engineers to determine what parts were failing over time in his Model T. When they came back and said there was one bolt that never failed the story is Ford told them to make it less strong and save a penny (something like that).

So my fiddling with the coolant water to glycol mix, and trying Water Wetter, and trying another OEM thermostat were things I could think of. Checking the fan belt tightness, super flushing the radiator with the AC cleaning product...great suggestions from our forum.

I bought the infrared temperature gun so next time it starts to overheat I'll take readings and maybe identify a restriction point.

Hey, you got the long reply - really meant for everyone!

 

[Rhino35]

Did you use the hose to flush out the cleaner that you applied? It's odd that so many people don't want to use a hose on their radiator because they think it will create mud, or the dust will build up from moisture, but nobody refuses to drive in the rain for that same reason.

It sounds like your fan belt is nice and tight.

Since you are still getting dirt out of your radiator, you really need to get the hose out and get it all cleaned out.

Yes, very thoroughly. When the dealership owner shook his head and told me rinsing it out was a mistake (years ago) I should have grabbed a pen and paper right then and there and written, "Tractors should never be used in rain", and said, "Be sure to alert future customers!"

Maybe I'll still do that!

 

[Rhino35]

And maybe try some A/C coil cleaner.

My most recent effort. We'll see in a week or two if it helped.

 

[YLee Kioti]

what is the kioti coolant you speak of kimo-sabe'????
I emailed my dealer and he said just get some of the green stuff.

So what coolant has anyone here been using on their Kioti?
Last time I visited this topic was a few years back and frankly don't remember much about it...heh..
I've only done one flush (since 2017) and it now has 1200 hours so this coming month, I gotta get it done after the final pasture cut.

For the fins, I use a 2 gallon pump sprayer with dawn and water to get the soap deep in there.
I use them to flush out condenser and radiator on all our vehicles at least every other year.
Then use:

Radiator Genie, High Pressure Air and Water Cleaning Wands​

 

[Alan46]

what is the kioti coolant you speak of kimo-sabe'????
I emailed my dealer and he said just get some of the green stuff.

So what coolant has anyone here been using on their Kioti?
Last time I visited this topic was a few years back and frankly don't remember much about it...heh..
I've only done one flush (since 2017) and it now has 1200 hours so this coming month, I gotta get it done after the final pasture cut.

For the fins, I use a 2 gallon pump sprayer with dawn and water to get the soap deep in there.
I use them to flush out condenser and radiator on all our vehicles at least every other year.
Then use:

Radiator Genie, High Pressure Air and Water Cleaning Wands​

View attachment 1690738

I use Preston green concentrated with a first flush using water only and let it run for at least 5 minutes. Then the flush according to instructions and then flush until water runs clear and fill w/50-50 solution!

 

[Williy]

I wonder if anyone checks the radiator hoses to see if
they can collapse on the older model tractors??

willy

 

[YLee Kioti]

TY Alan greatly appreciate that.
Simple is good and this is about as good a horse sense as it gets!
Ya'll have a good weekend...!

 

[Larry Caldwell]

Time for a cooling system service. Do not hose out a radiator. Water will turn the dust into concrete. Compressed air only. For a 10 year old tractor, it's time for a cooling system flush, new hoses, and a new thermostat. To resolve your questions and future questions, see if a shop manual and parts manual are still available. One of the things my dad taught me was, when you buy a tractor, buy the manuals.

 

[RayIN]

Try dropping a gear to see it it helps the overheating; or in your case going slower at the same RPM's.
I think hydro-drive tractors are designed to run the engine at high RPM continually.

 

[Kubota Red]

I have had a lot of experience with customers overheating their tractors. I would guess that at least 80% of the time, the radiator is not fully cleaned or the fins are damaged due to the way they were cleaned. If this was in my shop, the first thing I would do is completely remove the radiator and hold it up a light. Like I said, most of the time, it "looks" clean and clear when it is in the tractor, but it is not. It is a lot of work, but I have seen guys drive themselves crazy (and spend lots of time and money) trying to fix "other" problems that did not exist.

If this was already done/suggest, sorry for the repeat, I did not review every comment in the thread.

 

[Too many Kubotas]

Do not hose out a radiator. Water will turn the dust into concrete. Compressed air only.

In other words, never use a tractor in rain or snow?

 

[Larry Caldwell]

In other words, never use a tractor in rain or snow?

There's something to be said for servicing a tractor after you use it. Or maybe you get a lot of dust during snow storms?

 

[Too many Kubotas]

There's something to be said for servicing a tractor after you use it. Or maybe you get a lot of dust during snow storms?

Unfortunately, as much as I like to maintain my vehicles, tractors, and other machinery, changing fluids, filters, etc., something like that simply won't happen in real life.

For example, I did blow out the radiator at the end of the season, but much like last "winter" there's no snow yet. Or even rain really, so it's still being subjected to dust. Will it finally snow on Thursday? I don't know. Should I cold start the tractor and blow out the radiator again, in case it does?

And what about the regular vehicles? My cars and tow vehicles also get dust in their radiators. Should I pull over in a thunder storm or if it starts snowing, or "just" clean their radiators after they've been used?

Also, now I'm curious why dust in general doesn't turn to concrete when it gets wet, including on hot surfaces.

 

[Alan46]

In other words, never use a tractor in rain or snow?

Very good observation, TmK!!!

Unfortunately, as much as I like to maintain my vehicles, tractors, and other machinery, changing fluids, filters, etc., something like that simply won't happen in real life.

For example, I did blow out the radiator at the end of the season, but much like last "winter" there's no snow yet. Or even rain really, so it's still being subjected to dust. Will it finally snow on Thursday? I don't know. Should I cold start the tractor and blow out the radiator again, in case it does?

And what about the regular vehicles? My cars and tow vehicles also get dust in their radiators. Should I pull over in a thunder storm or if it starts snowing, or "just" clean their radiators after they've been used?

Also, now I'm curious why dust in general doesn't turn to concrete when it gets wet, including on hot surfaces.

!!