Kubota engine cooling problems

[BMXER10]

This is s silly one, but is the fan on the correct way? It should pull from the battery side and push out to the engine. Also, is the fan direct bolted so it will spin with the engine or is it on a clutch? (You would be able to spin the fan blade with the engine off) If a clutch it could be bad.

jb

Thats a good question. Im not at home, but I will check it out. I think its direct bolted.

 

[BMXER10]

I found a couple other forums that people talked about a bad head gasket could be causing this. How is that possible?

 

[cp1969]

I found a couple other forums that people talked about a bad head gasket could be causing this. How is that possible?

Because the bad gasket leaks combustion gases into the cooling system and the cooling system is not designed to take away that much heat. Cylinder gas heat is supposed to go out the exhaust.

Usually you will lose coolant, either out the exhaust or into the crankcase if this is what's wrong. Do you have to add coolant from time to time?

 

[cp1969]

There is no 'backwards' orientation to the fan, assuming this is the correct fam for the tractor. It probably will only go on one way and even if you can put it on 'reversed' you will find the blades still pull or push air in the same direction.

 

[chatme]

I see a few things, first thing I would do is get the right cap and that looks like the wrong battery. That battery looks way to big and is blocking off the hole grill and not letting air flow. what I would do is find out the size of the battery that came with that tractor new and see if the one you have is bigger. I think you will find that its not as thick and will set back away from the rad. letting air pass.

 

[RichNJKubota]

I'd pull the radiator and look inside. Look for crud clogging up the little tubes. Or just take it to a radiator shop. Around here they charge $25 for flushing the radiator with pressurized air and water. That usually cleans out crud. For more money they'll "rod" it out. They take the "tanks off the radiator and clean out each tube individually.

 

[Soundguy]

Wow.. what a horrible design.. I hope that engineer was executed after he made that... yikes! ( ok.. not executed.. but at least spanked and made to wear a pointy hat.. )..

I'll bet the battery LOOOOVES that proximity to the radiator.. coupled with the reduced ariflow... Only thing I've seen close to that is a thermosyphon Allis G.. but it's radiator has WAY much more airway than that one.. Id bet from size cues that my little allis-G 62 ci gas engine also has a larger radiator than that , probably larger, diesel engine...

Soundguy

Well, i mowed yesterday and it overheated again. This time the weather was pretty nice and the grass wasnt even tall, so the mower wasnt pushed hard. Back to square one. I printed off everyones suggestions and im going to work my way down the list.

-The thermostats installed, radiator partially drained and filled up with more water to get the % of antifreeze back down to 30% or so.

-The fan and belts are in excellent shape and tight so theres definitely no slipping.

My next step is to get the radiator cleaned at a radiator shop.

The previous owner told me he always had cooling problems, but Im not sure he was totally clear on how bad it was. He told me he was planning on moving the battery because it sits directly behind the radiator and doesnt allow much airflow. I attached pics!

 

[Volfandt]

I agree w/chatme, that battery is way too big and that doesn't look like the correct radiator cap either.
The battery on my BX23's D905 is smaller than whats in your pic and it has to spin a bigger engine. If possible try to slide that battery back towards the dash as far as it will go, center it in the compartment and clamp it down there, the idea is to open up more space for air to get to the radiator.
The radiator cap on my D905 engine is a 9lb cap. The test for it is to pump it up with a radiator/radiator cap tester to 13 lbs. It should bleed down to 9 lbs in 10 sec's or more. If it takes less than 10 sec's it needs to be replaced. This may be true for your engine's cooling system also.

Since it seems to be overheating without any appreciable load, it wouldn't hurt to flush the radiator a time or too and even pull it it to ensure that every nook and cranny is clean and unobstructed. Tractors that work good and last along time can accumilate alot of debris in those hard to get at places and once they get full the troubles then start.

Good luck

 

[SkunkWerX]

I agree with everyone who said the battery looked big, and is blocking the airway. Scooch it back away from the intake area, if at all possible.

Also, since you have to remove the radiator to take it to the shop, I'd go ahead and do a quick flush myself, into a 5 gallon bucket and inspect.
Check that wtaer pump while you are at it, and don't forget to flush the engine too.

And, since you will be doing "exploratory" sugery anyway, the head gasket won't be any easier to get to, than when you remove the radiator, may want to change it "on suspicion". Any white smoke out the exhaust? That is a sure sign of headgasket trouble. Sometimes you can smell it.

My last thought, don't hate me for this....

I gotta wonder how much overheating this motor has seen? If it's been donig this for a while, the guy may have gotten rid of it once it finally got so bad he couldn't run it for very long. So, do a compression check too.

 

[gemini5362]

Let me try to offer a couple of solutions that dont require a lot of money or disasembly. They are not fixes but they are something to help try to narrow down the problem.

1. Head gasket. Blowns head gaskets most of the time are indicated by a couple of things either one or both. Notice I did say most of the time. A classic blown headgasket symptom is water in the oil. Your oil will look grey when you check it. Another symptom is that when you take the radiator cap off your water in the radiator will have bubbles in it that is not always from a blown head gasket but sometimes it is an indication. IF you water is frothy that is pretty much of an indication that you might have a blown headgasket


2. Battery in the way. remove the battery attach a pair of jumper cables to it wrap something around the positive cable to make sure it does not touch metal and then start it up. set a piece of cardboard on the hood and set the battery there. Hold it in place with something such as a bungee cord and see if it gets hot


3. Time how long it takes it to get hot. drive the mower around without engaging the mowing deck and see if it still gets hot. If it doesnt then you can see if there is something in the mower deck that is a problem.




My kubota b6200 has the battery in front of the radiator and does not seem to have much room for air flow but it never gets hot.

 

[KennyV]

That’s not the right battery. Like chatme said… Put the correct size, small battery in and let air flow across the radiator.
Avoid future grief, I noticed in your second picture… The large red wire nut just to the right of the engine oil filter… That should be a fuse, probably around a 30 amp, It will prevent a fire if you should get a short in the electrical distribution. KennyV.

 

[BMXER10]

Thanks for all the great suggestions. I wasnt able to touch it all weekend, but hopefully tonight work will begin.

I hate to change out the battery since its brand new. I would rather free up the entire spot behind the radiator so Im going to install a battery box in the back and move it. Im also going to pick up a new radiator cap

Im not getting any weird smoke out the exhaust, just black smoke when I overload it in heavy grass. Im also not seeing any water in the oil, or bubbles in the radiator.

 

[BMXER10]

The deck is definitely not the cause of this. It spins freely by hand. Plus the mower still overheats after turning off the blades.

My to do list is getting huge.

 

[gemini5362]

Thanks for all the great suggestions. I wasnt able to touch it all weekend, but hopefully tonight work will begin.

I hate to change out the battery since its brand new. I would rather free up the entire spot behind the radiator so Im going to install a battery box in the back and move it. Im also going to pick up a new radiator cap

Im not getting any weird smoke out the exhaust, just black smoke when I overload it in heavy grass. Im also not seeing any water in the oil, or bubbles in the radiator.

unless you just want to do a project make sure the battery is the problem. You dont want to move it and then find out you have not corrected the problem.

 

[BMXER10]

Got a new battery today, much smaller than a car battery, but looks like it has decent cranking amps. I decided not to move the battery location, too much work after all. I also went ahead and picked up a bottle of radiator flush. Ill report back after this weekend. I also added a fuse to that red wire...

My question is can I do a compression check myself? Will a compression check tool from a car work with this engine? My dad has one from his mustang, but Im not sure if it will work for this diesel engine.

 

[DiezNutz]

My question is can I do a compression check myself? Will a compression check tool from a car work with this engine? My dad has one from his mustang, but Im not sure if it will work for this diesel engine.

You can do it yourself as long as you're comfortable pulling injectors & lines and keep the connections clean. But you need a DIESEL compression tester... the pressure is way too high for the regular (300psi) type.
Here's a cheap one:
Harbor Freight Tools - Quality Tools at the Lowest Prices

 

[BMXER10]

You can do it yourself as long as you're comfortable pulling injectors & lines and keep the connections clean. But you need a DIESEL compression tester... the pressure is way too high for the regular (300psi) type.
Here's a cheap one:
Harbor Freight Tools - Quality Tools at the Lowest Prices

Gotta love those cheap parts for a one time use. Thanks!

I assume this will tell me if theres a leak in the head gasket at all?

 

[cp1969]

Gotta love those cheap parts for a one time use. Thanks!

I assume this will tell me if theres a leak in the head gasket at all?

I doubt it. You're going to see a different reading for every cylinder even if the head gasket is fine. A cylinder that isn't leaking enough to put coolant in the oil or oil in the coolant is going to be awfully hard to detect with a compression test.

 

[Volfandt]

I assume this will tell me if theres a leak in the head gasket at all?

Yes a compression tester rated high enough for a diesel engine will definitely indicate if theres a compression leak (blown head gasket etc) but there are easier ways to tell.
You've already said that theres no brown or white milky substance in the oil which would indicate that coolant is leaking into the oil passages but you haven't indicated whether or not you've observed the coolant moveing in the radiator or if the coolant is bubbling and/or smoke is coming out of the radiator fill hole.

With the engine cold and the radiator filled full with water, remove the radiator cap then start the engine up and run it at a fast idle. After a while it should start to get warmed up enough to open the thermostat. At ths time you should see very visable coolant flow. If you observe coolant flow you can safely assume that both the waterpump and thermostat are working. Also observe the coolant for bubbling and/or smoke and/or steam emission. If you see either, you've probably have a blown head gasket.
I'd do this before I spent any additional $$$'s.
Good luck

 

[DiezNutz]

I assume this will tell me if theres a leak in the head gasket at all?

They beat me to it, but if the problem is as severe as you say and the head gasket is the culprit, then yes that should be reflected in the readings. Sorry, I didn't read the whole thing... I thought you just wanted to do a compression test for S's and giggles.
Try Volfandt's suggestions first. I'll throw this out there though: oil leaking into coolant or coolant leaking into oil isn't enough by itself to cause the kind of overheating you're seeing. I have a diesel truck with a leaky head gasket that's been pumping oil into my coolant and it doesn't run warm until the bottle is full of sludge. The kind of leak you'd be looking for is between the cylinder and coolant passages... (either leak in gasket or crack in cylinder wall), but it would also be making your cooling system pressure ridiculously high, probably to the point you'd be blowing hoses or rad caps off (seen it happen). So I'm leaning away from that, even.

You haven't told us yet whether cleaning the rad fins and the normal size battery has taken care of it. If that isn't it, then my next bets are T-stat, water pump or cruddy rad core (somewhat in that order).