BX Water Pump

[BlackforestBill]

Well it happened again. Last year I managed to over heat my 2000 BX2200 while mowing. Hadn't done a good job of clean the radiator fins. Over heat it a couple of times and you fry the water pump. At least that's what I was thinking at the time. Ordered new water pump. Turns out there are two different ones for the 2000 model year. Depends on when in the year your BX was made. One has smaller blades (that one fits mine). First one delivered was the wrong one, of course. Second one fit nicely. That was last August.

Moved a lot of snow over the winter. Put over 40 hours on the little beast with bucket and back blade. Now it's summer and I've been mowing again. 54" MMM, clean the radiator after every use. High RPMs for 3 hours or more to get the whole property done. Let it warm up before starting the task but just shut her down when done.

On my fifth time mowing I note the temps come up a bit higher and I have a small puddle under the engine in the garage the next day. Yep, water out of the weep hole on the water pump, again.

So what did I do wrong this time? I was careful to keep the fins clear. I watched the temp gauge. I'm using air to clean the debris off the MMM deck, the engine and the radiator. I'm blowing from the engine side. Coolant was a 50/50 mix. Oil is Kubota 10W30 (dino). It's just under 300 hours total use.

At $154 a pop this is starting to get expensive. At least I can do the R&R myself. Any ideas on how to prevent this in the future?

 

[MOPAULY]

Let me get this right...you replaced the first water pump that wasn't leaking, and now the you replaced it with is?

 

[milkman]

First I've ever heard of overheating frying a waterpump, does it have a plastic impeller?

 

[BlackforestBill]

I replaced the first one because it was leaking through the weep hole. Second one is now doing the same.

Impellers are metal but they aren't the problem. On automobile water pumps in general there's a ceramic or similar substance seal. When it goes bad water pours out the weep hole. Not sure what material Kubota uses. Usually goes bad due to high heat. Usually wont pour out the water when hot (expands and makes a decent seal), but as it cools down, and you're no longer around the tractor, it opens up and you get Niagara Falls.

 

[MOPAULY]

Is the fan off balance? If anything coming off of that shaft is I could see that causing early failure. I had a similar problem with my truck that caused me to replace 2 pumps in a 6 month period.

Otherwise I'm guessing a problem with the design of the pump....heat alone shouldn't kill the pump.

 

[BlackforestBill]

Is the fan off balance?

Hmmm, good question. I'll check it when we pull it for the swap. I was thinking too much heat shouldn't cause early failure and was wondering what might have caused the demise of the second one.

 

[638]

Belt too tight???


ron

 

[BlackforestBill]

Belt too tight???


ron

Good idea. It is pretty tight. I'll check the deflection before we tear it down and I'll make sure to set it to the setting in the owner's manual (I think I saw it in there).

-Edit- I just checked the deflection. Manual says between 1/4 & 3/8". It's in that range.

 

[MOPAULY]

Let us know what you find, I'd be curious to know, something has to be killing the pumps off that early.

 

[Volfandt]

Manual says between 1/4 & 3/8".

I just went out and checked mine (BX23) and I'd say I have about 1/2 or so deflection and that almost feels too tight.
Overheating may have eat up the seal in your original waterpump but that 2nd one should have lasted a whole lot longer than it did. I've only got 260 hrs without any problems w/the cooling system but this is not enough time to tell if something isn't engineered right but I'd guess that 2nd pump was defective or the belt was too tight and that it is not an engineering problem.
I've not heard of many waterpumps needing changed on BX's here on tbn so I wouldn't think that they all have short lifespans.
I've never had to adj my belt and I may even loosen it abit when I do the 300 hr. I just know from having to wrench auto's that an overly tight fan belt will eat up waterpumps and alternator bearings, btdt....
Good luck