Kubota Subcompact BX24 Still wants to overheat!

[Skysurfer]

Changed the thermostat and checked on all the usual troubleshooting problems with the cooling system and airflow to radiator and air filter. Fuel also it good and clean. Belt is good. Coolant is good too.
My nest move is the water pump.
Has anyone had any problems with the water pump on this model before?
My BX24 has 400 hours on it only and there is no other indication that there is a problem with the water pump. Fan and shaft seem to be alright.
Another water pump is easy enough but wondering if anyone has any possible ideas or has had similar trouble.
Just looking for some input and insight.
Thanks much.
All the best for 2011.

 

[Kubota_Man]

I have a BX 24 with a 54" MMM and a grass catcher. I am always having to clear the screen that is SUPPOSED to take keep debree from being sucked into the radiator. So I have to clean the screen twice as often as the radiator fins both of which gets caked with dirt and grass So as the Diabites commercial says check your screen and radiator and check them often.

P.S. A little post oporation TLC is a good thing as well. I rinse the underside with a garden hose every time I put her up for the night

Hope that helps

 

[kuboman]

Changed the thermostat and checked on all the usual troubleshooting problems with the cooling system and airflow to radiator and air filter. Fuel also it good and clean. Belt is good. Coolant is good too.
My nest move is the water pump.
Has anyone had any problems with the water pump on this model before?
My BX24 has 400 hours on it only and there is no other indication that there is a problem with the water pump. Fan and shaft seem to be alright.
Another water pump is easy enough but wondering if anyone has any possible ideas or has had similar trouble.
Just looking for some input and insight.
Thanks much.
All the best for 2011.

You may want to try a flow test through the radiator. It may be plugged up on the inside. Just a thought. I doubt it is the water pump and if you have cleaned the radiator from the outside then that leaves the inside. I have seen many radiators plugged internally.

 

[Kubota_Man]

Also check both sides of the radiator top to bottom and left to right. You may be suprised as to how much gunk can get in to places you can't see all to well. My BX24 has about 650 hrs on it and the gunk build-up is the only thing (so far) that causes heat build-up.

 

[IC-Smoke]

Im around 1200 hrs on my bx and it tends to run on the warm side but even in August running the 54"mmm and kubota bagger (runs off rear pto) I dont have an issues with it overheating.

Personally I think it is the fact that the mower isnt getting enough air. I have pulled the engine sheild/grille piece off and it runs right in-between cool and hot with no issues.

You could run the coolant product that claims to lower your coolant temps, Im not sure of the brand name.

.02
Ian

 

[Skysurfer]

Spoke with Les at Messick's and he came up with the radiator being a problem too. Apparently there is a plastic reservoir (2) in the radiator that can break down particularly when heated a bit. Gunks up the radiator with a bit of black residue.
The little sub compact machines don't have much tolerance for anything when it comes to not getting good cooling, also keep in mind where the radiator is mounted (down wind of the heat of the engine).
Kubota Man, you nailed it I think with the flow check on the radiator.
Plans now: Looking at a flow check, if I can get it done here somewhere. And a new radiator probably.
Thanks again everyone for you words of advice, ideas, and help.
All the best.

 

[Kubota_Man]

Although I do see a slight problem. You are having issues with overheating while you are mowing your lawn in Janaury and I an plowing and snowblowing snow and dealing with below 0 degree F temps Does anyone else see the irony in this

Anyway glad to see you are on track to getting your lawn in tip top shape.

A scenic pic of the Big Island would help

 

[Skysurfer]

It is always a challenge with the BX24 and the engineering of the radiator; where it is and the susceptibility of the radiator to clog up with fine grass to keep the sub compact tractor running cool.
What I have found is besides keeping the fan belt tight and the removable particle screen covering the rear (intake!) of the radiator clean is that this little system is a bit challenged still. It is a little machine and the temperature tolerance, particularly when under a load is minimal.
I have found that when removing the radiator entirely (not a fun job, tiny spaces for nuts, bolts, screws) and taking it out, there is a distinct possibility of the small aluminum fins being covered and coated with tiny debris and quite a factor.
I made an attachment for my vacuum to get in to the very small area on the "intake" side of the radiator with the screen out. It works to some extent. I think a good nozzle on the air compressor is essential also. Still probably actually take the radiator out of the machine from time to time to actually be able to effectively clean it.
Anyone taken the radiator out of that compartment and mounted it where it can get some fresh cool air? That's a concept. I would mount it right on top of the hood, might need a bit of extra cushion on the seat to see over it! Would run cooler though.
Seriously, hope these innuendos help some one. I sure have wasted too much time on this sub compact cooling issue.

 

[fossenbeck]

My BX24 also started overheating recently to the point where the coolant is literally boiling in the recovery tank. I don't know for sure what brought on the overheating but a possibility is sludge in the coolant. I tend to do many of the longer term PM items at half the recommended interval so I flushed my cooling system at 400 hours. After draining the system I used Prestone Super Flush to clean the system, then drained and refilled with 50/50 anti freeze/water mix. I later learned that if the flush chemical is not completely removed (which takes more than one drain/refill) it reacts with anti freeze to form a sludge. I believe this sludge clogged my radiator. I has no visible flow and there was a jelly like sludge in the mix. I successfully cleared the radiator by pressure flushing repeatedly and as a precaution (and since I had it torn down) also replaced the thermostat, hoses, and water pump. When I purchased the new water pump my Kubota dealer told me that water pump failures are not uncommon on the BX24.

BTW "(also keep in mind where the radiator is mounted (down wind of the heat of the engine)." The BX24 radiator is actually not downwind of the engine. Its fan PULLS air through the screen and radiator from the operator area toward the front end. That screen/grill below the steering wheel in the operator area serves the function of the grill on your car/truck. This design feature is intended to prevent hot air from the engine compartment from blowing toward the operator.

 

[cerlawson]

Seeing this overheating on many posts,when I bought my BX, I noted that the temperature sensor sits very close to the muffler. Therefore, between the two I hung a double layer of aluminum foil as an insulator. Never has the temp gauge gone above half way.

 

[fossenbeck]

Another thought on BX24 overheating; as many of you have accurately noted one of the biggest causes of overheating is reduction of air flow across the radiator's cooling fins due to foreign matter clogging the screens and radiator.

One of many, many examples of Kubota's lousy design engineering is the fact that the radiator is open from below to the ground (and mower deck when one is mounted). They were smart to place two screens in the main intended flow path between the operator area and the radiator but the fan also creates a large amount of airflow from underneath the radiator. This oversight allows a wide open flow path for dry mowing debris (the biggest offender) to clog the second screen along with a significant amount of flow that bypasses both screens.

I'd like to build a 5 sided box screen to mount at the bottom of the radiator to reduce this problem.

Have any of you tried this?