Kubota Suddenly Running a Bit Warmer?

[Putneymountain]

We have a 2 year old Kubota M62 with about 400 hours on it. In all the time we've had it, the temperature has never gotten above about 1/3 of the measurement dial. We always assumed this was normal.

Suddenly, from one day to the next, its temperature is right in the middle. This was surprising in particular because it has suddenly gotten colder here in New England - so it's not a change in the environmental temperature.

The radiator is completely clean.

The coolant overflow tank is completely full.

Questions:

What should this tractor's temperature measurement normally be? 1/3 or ½ up the dial?

Was the tractor’s operating temperature unusually cool during its first two years and has now become normal?

Or was it normal before and now it is a bit warmer than it should be?

What would be the likely cause for a change like this? The thermostat?

Anything we can do to sort out the close?

Thanks in advance for any help.

 

[85Hokie]

The dial is simply a reference point - unless it is calibrated to a specific number - it as you mentioned is a point of where it was and now where it is.

The best thing to do is find out HOW hot the water really is - a simple way is to measure the top of the radiator neck and see what that says, something around 200+F would a good base number and then find out what the bottom neck of the radiator is reading - something like 100+ F would be a good start.

YOU must get everything up to hot before doing any of this - bailing, cutting grass or whatever - get the water up to that mid point on the meter.

AS far as what could be wrong - the sending unit which can get off over time - the resistance will change and thus give reading that is a bit different than before or the meter itself could be going bad too.

I am betting the water is getting hotter - for a reason we do not know yet - you say the radiator is CLEAN inside and out? HOW sure?

Is the fan belt tight? IF it is loose, it will allow the engine to run hotter

Thermostat could be not opening all the way - but I bet that it is not the problem.

And lastly there could be a small pin hole in the head gasket - I do not think this is the problem either.

 

[Lug66]

Did the cooling system get serviced (drain, flush, refill) at two years?

 

[jaxs]

I don't intend disrespect for you nor our members but this isn't something to surf the net for free advice on. A single overheating event for any diesel is almost certain to cause life shortening engine damage and risks total destruction.. This isn't your grandpa's old gasoline motor that could spew steam then cool down and be ok. At minimum use a lazar thermometer to read temperature at various places after engine reaches operating temperature then compare to FACTORY SPECS. Smart money is turning it over to a pro for analysis and chat about bucket hooks on the web.. Hopefully it's only a wacky gauge or sender but internet buds can wag at it til Christmas and still can't determine what it is.

 

[GreensvilleJay]

re: The coolant overflow tank is completely full.

hmm... usually the level should be 1/2way between 'min and max' lines

if the tank is 'completely full', that would indicate a problem, unless of course your manual says it's supposed to be 'completely full'.

along with other things to cause a gauge to read 'different', the CVR feeding power to the gauge could be damaged. Most 'old school' systems have a Constant Voltage Regulator to power the temp and fuel gauges to 'average out' readings to a more 'constant' value. If your tractor is 'old school', it's another possible source to look at. Kinda important to have the WSM electrical section to see what are normal/nominal values for sensor and readings.

 

[RCW]

Like others mentioned, I’d probably start with an infrared thermometer.

Any guesses about whether it’s hotter or not is speculation without some data.

The spade connector on my BX temperature sending unit needs periodic cleaning.

I’ve had times the gauge read VERY close to H within 2 minutes of starting from cold.

Temperatures with a thermometer read just above 100 F; nothing was really hot except the reading on the gauge. I could touch most engine parts with my hand.

Get a thermometer and clean and put some dielectric grease on your sending unit….start simple. Make sure radiator is clean.

 

[TheOldHokie]

We have a 2 year old Kubota M62 with about 400 hours on it. In all the time we've had it, the temperature has never gotten above about 1/3 of the measurement dial. We always assumed this was normal.

Suddenly, from one day to the next, its temperature is right in the middle. This was surprising in particular because it has suddenly gotten colder here in New England - so it's not a change in the environmental temperature.

The radiator is completely clean.

The coolant overflow tank is completely full.

Questions:

What should this tractor's temperature measurement normally be? 1/3 or ½ up the dial?

Was the tractor’s operating temperature unusually cool during its first two years and has now become normal?

Or was it normal before and now it is a bit warmer than it should be?

What would be the likely cause for a change like this? The thermostat?

Anything we can do to sort out the close?

Thanks in advance for any help.

Middle of the NORMAL range is nothing to get excited about. That's pretty much where it should be. Your lower third is a lot lower than my L3901.

Why did it change - who knows. Could be as simple as the thermostat is not opening as early or as wide as it used to. Keep an eye on it but don't fix it until it's really broke.

Dan

 

[RCW]

Middle of the NORMAL range is nothing to get excited about. That's pretty much where it should be. Your lower third is a lot lower than my L3901.

Why did it change - who knows. Could be as simple as the thermostat is not opening as early or as wide as it used to. Keep an eye on it but don't fix it until it's really broke.

Dan

Dan said it better than I did.

Just watch and take temperatures if you need/want to get some comparables.

I wouldn’t try to fix something that isn’t broken.

It is an important thing as an overheat can cause engine damage. Great thing that you’re aware.

 

[rc51stierhoff]

As mentioned above:
1. fluid is good / correct?
2. Changed at service interval?
3. Cap on correctly (could cause a pressure change if not which could cause increase in temp)
4. Get some data…personally a lot of OEM gauges at least on cars (newer maybe be a little more accurate) and powersport products they are not terribly accurate and it could take as much as 50 degrees for them to move…I am not saying your is, I am saying they are not as accurate as we might want from a thermometer…but I don’t really know that is true for tractors…

either way I think the recommendation on getting some data might help determine if there is a problem at all to even worry about before paying the piper.

 

[lugbolt]

can't say this is your issue but i've had the thermostats stick open in the past (they are failsafe, they stick open but not closed-usually). When stuck open the engine really has a tough time warming up. But then, it gets unstuck and works normally. May be what your issue is. Or may be something else. But I've had that happen before.

coolant does "wear out" over time, so be sure to flush it every so often for preventing other issues. RTV's, I did TONS of them. The coolant would get acidic, start eating at the inside of the block, creates rust and that rust will plug up the head gasket steam holes. Then engine overheats, usually cracks the head. Pretty expensive on tractors, the RTV's were too terribly bad. ZD mowers had this issue too but usually in my case (since RTV's were selling very well here at that time) usually rtv's 900's and 900xt's mostly.

 

[skeets]

Have you been using it in very dust conditions? I know you said the rad was clean ,I guess you have washed it out with a water hose, something else maybe check your fan belt if it is loose ,, I dont know just look for the easy stuff first

 

[yamiacaveman]

I recently had the same issue with my 10 year old b3200. I changed everything and the next step was to pull my radiator out -- but I found about a 3 foot wand air attachment at probably harbor freight or some place like that -- It easily fit down the outside of the radiator, blew everything out, especially at the bottom. Thats all it was. works fine. I have always tried to keep the radiator clean, but this was a hard place to get to, so was I in some heavy stuff or a gradual build up over time??? Anyway if you try my lazy way be careful not to bend the fins o the radiator.

 

[GreensvilleJay]

great, reminds me now that I have to BLOCK 1/2 my rad pretty soon... the BX23S needs MORE heat next month....and next ,and next and.....sigh..

 

[dvcochran]

My experience with the newer style radiators which your Kubota has is that they will look clean when they actually are not.
We do a Lot of hay with two Kubota's (and two NH tractors). I have to keep the Kub's on a tighter cleaning schedule than the NH tractors.
After every use, (back) blow out the radiator with medium pressure compressed air using a radiator cleaning tool with fan tip. If cutting (or bush hogging) or baling in dusty conditions, this frequency may be as often as every 3-4 hours.
After every finished field or days of use, while the tractor is still warm, I blow out the radiator/evaporator with air, spray down radiator/evaporator with a good organic coil cleaner (NOT acid), wait 10-15 minutes and hose out very well with water. Then blow out until dry and let the tractor run at high idle for several minutes before parking. Seeds are just insidious in a radiator and hard to get out sometimes.
Kubota's just don't have as much radiator overhead as the NH tractors have. But they will out work them horsepower to horsepower every time.

As far as going purely off the dash temp gauge, it is a 'rough' estimate, and just about every tractor is going to read a little differently. Making sure the wiring is in good shape first, Coleman Equipment has the sending unit for about $50 so it would be a fairly cheap, easy 'part swap' test. But do the simple, basic stuff that others have listed first. Clean, clean, clean, check the radiator cap, work the tractor hard and use an IR temp gun to get a real idea of the engine temp. And NO, the overflow should Not be completely full. When you have the cap off and engine running and hot, look for bubbles. They would be a bad sign of an engine problem like a head gasket, and it will cause coolant to 'puke' into the overflow.

You are getting flooded with info, so get a baseline with the simple stuff first and work from there.

 

[Putneymountain]

The dial is simply a reference point - unless it is calibrated to a specific number - it as you mentioned is a point of where it was and now where it is.

The best thing to do is find out HOW hot the water really is - a simple way is to measure the top of the radiator neck and see what that says, something around 200+F would a good base number and then find out what the bottom neck of the radiator is reading - something like 100+ F would be a good start.

YOU must get everything up to hot before doing any of this - bailing, cutting grass or whatever - get the water up to that mid point on the meter.

AS far as what could be wrong - the sending unit which can get off over time - the resistance will change and thus give reading that is a bit different than before or the meter itself could be going bad too.

I am betting the water is getting hotter - for a reason we do not know yet - you say the radiator is CLEAN inside and out? HOW sure?

Is the fan belt tight? IF it is loose, it will allow the engine to run hotter

Thermostat could be not opening all the way - but I bet that it is not the problem.

And lastly there could be a small pin hole in the head gasket - I do not think this is the problem either.

Thanks - we've ordered an infrared device. Fan belt is tight. Engine oil looks fine.

 

[Putneymountain]

Did the cooling system get serviced (drain, flush, refill) at two years?

No flush - the dealer had it in their shop and didn't think it was necessary. Any idea why a sudden change from one day to the next? Thanks.

 

[Putneymountain]

re: The coolant overflow tank is completely full.

hmm... usually the level should be 1/2way between 'min and max' lines

if the tank is 'completely full', that would indicate a problem, unless of course your manual says it's supposed to be 'completely full'.

along with other things to cause a gauge to read 'different', the CVR feeding power to the gauge could be damaged. Most 'old school' systems have a Constant Voltage Regulator to power the temp and fuel gauges to 'average out' readings to a more 'constant' value. If your tractor is 'old school', it's another possible source to look at. Kinda important to have the WSM electrical section to see what are normal/nominal values for sensor and readings.

Sorry - I should a said the coolant level was at the correct middle point. This is an almost new machine.

 

[Putneymountain]

Like others mentioned, I’d probably start with an infrared thermometer.

Any guesses about whether it’s hotter or not is speculation without some data.

The spade connector on my BX temperature sending unit needs periodic cleaning.

I’ve had times the gauge read VERY close to H within 2 minutes of starting from cold.

Temperatures with a thermometer read just above 100 F; nothing was really hot except the reading on the gauge. I could touch most engine parts with my hand.

Get a thermometer and clean and put some dielectric grease on your sending unit….start simple. Make sure radiator is clean.

Thanks - will do. Does anyone know where the temperature sending unit is on an M62?

 

[Putneymountain]

My experience with the newer style radiators which your Kubota has is that they will look clean when they actually are not.
We do a Lot of hay with two Kubota's (and two NH tractors). I have to keep the Kub's on a tighter cleaning schedule than the NH tractors.
After every use, (back) blow out the radiator with medium pressure compressed air using a radiator cleaning tool with fan tip. If cutting (or bush hogging) or baling in dusty conditions, this frequency may be as often as every 3-4 hours.
After every finished field or days of use, while the tractor is still warm, I blow out the radiator/evaporator with air, spray down radiator/evaporator with a good organic coil cleaner (NOT acid), wait 10-15 minutes and hose out very well with water. Then blow out until dry and let the tractor run at high idle for several minutes before parking. Seeds are just insidious in a radiator and hard to get out sometimes.
Kubota's just don't have as much radiator overhead as the NH tractors have. But they will out work them horsepower to horsepower every time.

As far as going purely off the dash temp gauge, it is a 'rough' estimate, and just about every tractor is going to read a little differently. Making sure the wiring is in good shape first, Coleman Equipment has the sending unit for about $50 so it would be a fairly cheap, easy 'part swap' test. But do the simple, basic stuff that others have listed first. Clean, clean, clean, check the radiator cap, work the tractor hard and use an IR temp gun to get a real idea of the engine temp. And NO, the overflow should Not be completely full. When you have the cap off and engine running and hot, look for bubbles. They would be a bad sign of an engine problem like a head gasket, and it will cause coolant to 'puke' into the overflow.

You are getting flooded with info, so get a baseline with the simple stuff first and work from there.

Thanks - very good advice. This machine is not used agriculturally - its used to move logs in our woodlot. The radiators always look essentially new.
We're going to measure the temperature - still don't know why it changed one day to the next....

 

[TheOldHokie]

Thanks - very good advice. This machine is not used agriculturally - its used to move logs in our woodlot. The radiators always look essentially new.
We're going to measure the temperature - still don't know why it changed one day to the next....

Well to be picky you don't know the temperature changed. Your gauge reading changed.

Unless you have a previous temp measurement measuring temp now is simply going to tell you what is at this juncture. What do you think it should measure?

Dan