Rhino35
Silver Member
- Joined
- May 28, 2013
- Messages
- 146
- Location
- Independence, KY
- Tractor
- 2013 Kioti DK 40 SE Hydro and two Cub Cadet riding lawn mowers
Seeking Expert Advice,
I could really use some insight from forumites. I apologize for the long post, but a detailed initial post will short cut questions and allow you to visualize my situation. I am a tractor owner with 12 hilly acres in Northern Kentucky. I use my tractor to smooth my gravel driveway, move gravel, move topsoil, and occasionally bushhog hilly land.
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).
Other than the overheating issue, which has been going on really since new but was excused by dealership as the result of clogged radiator screen, or clogged radiator fins, and therefore temporary (yes, hogging got debris to clog so...) and "normal" (translation - nothing to do under warranty), this compact utility tractor is a good fit for my property and occasional needs. I have never let the temperature gauge climb above the white operating range line into red line. When it starts climbing, after I've been hogging for 20-30 minutes or so, I'll work a little longer while it creeps up, then stop, usually shut down the engine (but idling sometimes while blowing things clean - the manual says to idle before shutdown), and use an electric leaf blower which I carry in the bucket to blow any accumulated vegetative (who doesn't like that word *grin*?) debris from bushhogging off the engine/engine radiator/oil cooler screens. Sometimes when it starts this climb towards overheating there ISN'T any visible accumulated debris on the removable screens, sometimes a little, sometimes a lot (in October) hogging thick summer growth bushes, saplings and dense plants/grasses so this leads me to believe I may have a restrictive thermostat problem. But...I replaced the thermostat (more below) so what are the odds two are "defective"? My workaround for nine years which prolongs the temperature gauge's climb towards red line (whenever it may start that), and incidentally is the marvel of my farming neighbors watching their "city kid" transplant bush hog, and which sometimes even stabilizes the needle a few needle widths short of the high white line, is to open the hood fully and bush hog with it wide open. Since I can't see around the open hood while seated I have gotten into the habit of engaging the "go" pedal's "cruise control" magnet, standing up over on the high side (while hogging across the hillside, never up or down) like an 1800's sailing ship sea captain and steering with one hand. All I need is a shanty hat and a pipe to complete this picture. And yes, I know standing up on a moving tractor is particularly stupid behavior, and I agree I have to finally fix the overheating problem before I topple off and get run over.
I searched this forum a few years ago for advice on removing the thermostat altogether and found one or two tractor owners who said they'd removed theirs and never had problems. But the consensus is "replace the thermometer because the engine needs it". The reason mostly given for overheating issues (and in articles I've read) is that without fluid flow slowing from a properly functioning restrictive thermostat coolant flows TOO quickly through the radiator and therefore it doesn't have time to cool inside the radiator. But what about thermostats that don't open up correctly. Or, maybe in what did/is happening with my TWO thermostats at some point even when wide open they still restrict flow too much? The other reason is the engine will run too cold and get poor fuel economy - or even suffer some kind of internal damage. I don't know about the weather environments where this runs "too cold" without a thermostat advice would be a problem, but my cold environment is controlled. My detached garage is heated and I set the temp at 40F in winter. I haven't yet needed to use the tractor on a cold day. Barring a utility electrical grid failure in the coldest part of winter the temperature inside my garage for engine start/anti-freezing will never be lower than 40 degrees.
What I've done over the years and particularly in summer/fall of 2023...
Blown out radiator fins as best I could with fan and fan belt in place, both ways, after every use with a leaf blower, and several times with high pressure compressor air ( with the little gun- shaped attachment)
Rinsed out the radiator fins with a regular hose the second year I owned the tractor - was admonished by dealership bad idea because fine vegetative debris not fully rinsed out will dry to a paste and stick.
Okay...so then I liberally sprayed brake cleaner fluid into the radiator fins, let that soak for a couple of hours, then rinsed it with a hose AND, carefully, a pressure washer at distance (dreading bending the fragile cooling fins inside the radiator)
Replaced hydraulic fluid and filters - 400 hour service
Replaced front axle fluid - it is a selectable four wheel drive tractor
Replace engine oil and filter - do this after hogging every fall
Cleaned/replaced air filter - a neighbor told me dirty air filters can cause engine overheat - not the issue.
Drained radiator coolant - it looked pretty good to me.
Replaced OEM thermostat with Kioti OEM thermostat - identical overheating problems!
Replaced radiator coolant with Kioti coolant, but adjusted the mix to 40% coolant and 60% distilled water because I read water actually is a better fluid to carry away heat.
Put in a small bottle of "Water Wetter", which a motorcycle racing buddy said is used in water-cooled motorcycle engines. It is supposed to increase the heat transfer more than coolant and water alone.
Checked the fan belt tension - the fan is turning correctly.
Nothing changed how the engine warms up correctly (about six minutes at idle to get to the 11 o'clock needle position inside the white lines), or to really alter this temperature climb thing it does after running for awhile with a load on it (bush hogging grass or the meadowland).
What I think I'll do next, unless convinced a smarter course of action is recommended by people with experience, is once again use brake fluid and a pressure washer to try and clean the radiator fins. If that doesn't fix it then remove the thermostat and just see what happens. It's easy to do. If it overheats sooner, or faster, then it wasn't two malfunctioning, overly restrictive OEM thermostats. Maybe a water pump putting out too little flow? Maybe radiator fins still too clogged with fine, pasty, debris? Rods aside the radiator clogged? A design flaw of this model where the radiator is just too small? Or maybe just...a heavy bush hog, heavy grass/meadow vegetative material, steep hills, and a high total weight of the tractor with implements - which means I have the wrong tractor for my needs.
So that's it - and thanks for reading. The owner of the dealership and I have talked about my nuisance overheating problem a half dozen times over the years. He thinks I may still have clogged fins. His shrugged-shoulder advice is, "bring it in and let my mechanics diagnose the problem". He charges $100 each way to trailer six miles BTW and $160/hour labor. I dunno...it's the Information Age...and I'm appealing to you forumites before I take the step of turning it over to the dealership.
Rhino
I could really use some insight from forumites. I apologize for the long post, but a detailed initial post will short cut questions and allow you to visualize my situation. I am a tractor owner with 12 hilly acres in Northern Kentucky. I use my tractor to smooth my gravel driveway, move gravel, move topsoil, and occasionally bushhog hilly land.
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).
Other than the overheating issue, which has been going on really since new but was excused by dealership as the result of clogged radiator screen, or clogged radiator fins, and therefore temporary (yes, hogging got debris to clog so...) and "normal" (translation - nothing to do under warranty), this compact utility tractor is a good fit for my property and occasional needs. I have never let the temperature gauge climb above the white operating range line into red line. When it starts climbing, after I've been hogging for 20-30 minutes or so, I'll work a little longer while it creeps up, then stop, usually shut down the engine (but idling sometimes while blowing things clean - the manual says to idle before shutdown), and use an electric leaf blower which I carry in the bucket to blow any accumulated vegetative (who doesn't like that word *grin*?) debris from bushhogging off the engine/engine radiator/oil cooler screens. Sometimes when it starts this climb towards overheating there ISN'T any visible accumulated debris on the removable screens, sometimes a little, sometimes a lot (in October) hogging thick summer growth bushes, saplings and dense plants/grasses so this leads me to believe I may have a restrictive thermostat problem. But...I replaced the thermostat (more below) so what are the odds two are "defective"? My workaround for nine years which prolongs the temperature gauge's climb towards red line (whenever it may start that), and incidentally is the marvel of my farming neighbors watching their "city kid" transplant bush hog, and which sometimes even stabilizes the needle a few needle widths short of the high white line, is to open the hood fully and bush hog with it wide open. Since I can't see around the open hood while seated I have gotten into the habit of engaging the "go" pedal's "cruise control" magnet, standing up over on the high side (while hogging across the hillside, never up or down) like an 1800's sailing ship sea captain and steering with one hand. All I need is a shanty hat and a pipe to complete this picture. And yes, I know standing up on a moving tractor is particularly stupid behavior, and I agree I have to finally fix the overheating problem before I topple off and get run over.
I searched this forum a few years ago for advice on removing the thermostat altogether and found one or two tractor owners who said they'd removed theirs and never had problems. But the consensus is "replace the thermometer because the engine needs it". The reason mostly given for overheating issues (and in articles I've read) is that without fluid flow slowing from a properly functioning restrictive thermostat coolant flows TOO quickly through the radiator and therefore it doesn't have time to cool inside the radiator. But what about thermostats that don't open up correctly. Or, maybe in what did/is happening with my TWO thermostats at some point even when wide open they still restrict flow too much? The other reason is the engine will run too cold and get poor fuel economy - or even suffer some kind of internal damage. I don't know about the weather environments where this runs "too cold" without a thermostat advice would be a problem, but my cold environment is controlled. My detached garage is heated and I set the temp at 40F in winter. I haven't yet needed to use the tractor on a cold day. Barring a utility electrical grid failure in the coldest part of winter the temperature inside my garage for engine start/anti-freezing will never be lower than 40 degrees.
What I've done over the years and particularly in summer/fall of 2023...
Blown out radiator fins as best I could with fan and fan belt in place, both ways, after every use with a leaf blower, and several times with high pressure compressor air ( with the little gun- shaped attachment)
Rinsed out the radiator fins with a regular hose the second year I owned the tractor - was admonished by dealership bad idea because fine vegetative debris not fully rinsed out will dry to a paste and stick.
Okay...so then I liberally sprayed brake cleaner fluid into the radiator fins, let that soak for a couple of hours, then rinsed it with a hose AND, carefully, a pressure washer at distance (dreading bending the fragile cooling fins inside the radiator)
Replaced hydraulic fluid and filters - 400 hour service
Replaced front axle fluid - it is a selectable four wheel drive tractor
Replace engine oil and filter - do this after hogging every fall
Cleaned/replaced air filter - a neighbor told me dirty air filters can cause engine overheat - not the issue.
Drained radiator coolant - it looked pretty good to me.
Replaced OEM thermostat with Kioti OEM thermostat - identical overheating problems!
Replaced radiator coolant with Kioti coolant, but adjusted the mix to 40% coolant and 60% distilled water because I read water actually is a better fluid to carry away heat.
Put in a small bottle of "Water Wetter", which a motorcycle racing buddy said is used in water-cooled motorcycle engines. It is supposed to increase the heat transfer more than coolant and water alone.
Checked the fan belt tension - the fan is turning correctly.
Nothing changed how the engine warms up correctly (about six minutes at idle to get to the 11 o'clock needle position inside the white lines), or to really alter this temperature climb thing it does after running for awhile with a load on it (bush hogging grass or the meadowland).
What I think I'll do next, unless convinced a smarter course of action is recommended by people with experience, is once again use brake fluid and a pressure washer to try and clean the radiator fins. If that doesn't fix it then remove the thermostat and just see what happens. It's easy to do. If it overheats sooner, or faster, then it wasn't two malfunctioning, overly restrictive OEM thermostats. Maybe a water pump putting out too little flow? Maybe radiator fins still too clogged with fine, pasty, debris? Rods aside the radiator clogged? A design flaw of this model where the radiator is just too small? Or maybe just...a heavy bush hog, heavy grass/meadow vegetative material, steep hills, and a high total weight of the tractor with implements - which means I have the wrong tractor for my needs.
So that's it - and thanks for reading. The owner of the dealership and I have talked about my nuisance overheating problem a half dozen times over the years. He thinks I may still have clogged fins. His shrugged-shoulder advice is, "bring it in and let my mechanics diagnose the problem". He charges $100 each way to trailer six miles BTW and $160/hour labor. I dunno...it's the Information Age...and I'm appealing to you forumites before I take the step of turning it over to the dealership.
Rhino
I agree with the dealer. But if only 6 miles to the dealer, why not just drive it to them? That would save you $200 and they likely can determine what is going on. Have you used a temp gun to verify it is actually overheating? Could be a simple bad connection on the sending unit itself. If the technician at the dealer is good, it will be no problem for him to solve this issue.
