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B7800 Waterpump overheating problems

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czrider
Join Date: Aug 2008
Posts: 7 jasper, georgia
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2008-08-31          156424


Hi, Haven't been on the boards in ages...I found TractorPoint a several years ago when shopping for a compact tractor...had to re-register as I forgot my original userid, etc.
My question pertains to recurring cooling system problems on my 300 hour B7800 tractor My problems started a couple of years ago when the tractor had around 160 hours and was just beyond the 3 year warranty period. My wife had been mowing for several hours when the tractor shut down on her. I investigated and found the radiator completely dry. I re-filled the cooling system, restarted the tractor and was very relieved when everything seemed OK. I discoverd, the next time I used the tractor that the waterpump was weeping coolant from the hole underneath the impeller shaft. My theory at the time was that the tractor overheated due to chaff blocking the airflow causing the tractor to overheat and boil off all the coolant - my wife is not real good about watching the gauges. At the time of this first overheating incident, she was mowing ~4 inch fescue, not hard mowing at all, but she had been at it for at least 4 hours or more. I attributed the waterpump failure to running dry, I now suspect that the waterpump was the culprit all along.
I replaced the pump with a new part from the dealer, flushed and re-filled the radiator with a 50-50 mix of coolant. Since the initial incident, I have religiously cleared the chaff from the grill and removeable screen in front of the radiator after ever hour or so of mowing; I have noticed that the temperature guage does drop a bit after clearing the chaff.
I counted my blessings that my tractor had apparently escaped major damage from being run without coolant. Yesterday, I found that my cooling problems were not over. The tractor started heating up on me during some very easy mowing. I checked and found that the new, $160 waterpump was sling coolant from around the shaft again!
Has anyone else experienced similar problems? I cannot believe that these waterpumps routinely fail after 150 hours or so. My dealer said he has only sold this particular waterpump on high hour excavators, which, apparently use the same pump. I would appreciate any advice as to why this is happening. I would also be interested if anyone has a source for aftermarket waterpumps that are not so pricey. Thanks in advance for any advice. Jim

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B7800 Waterpump overheating problems

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harvey
Join Date: Sep 2000
Posts: 1545 Moravia, NY
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-08-31          156425


With luck like that I would not got to Vegas this year.

I have seen new pumps fail also but it's rare. I'd whine at dealer. I'd also be concerned about the quality of anti-freeze or the water you use to mix.

You are loosing waterpump seals. That is unusual given the hours. ....

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B7800 Waterpump overheating problems

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czrider
Join Date: Aug 2008
Posts: 7 jasper, georgia
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2008-08-31          156426


Harvey,
I do intend to whine a little at the dealer sometime next week. As to the type of coolant; I used Prestone mixed 50/50 with well water...the same coolant and water used in all our cars & trucks as well as my old 2240 John Deere. I may use the pre-mix coolant next time, although I don't think my water is the problem. I'll let everyone know how I make out with the dealer. ....

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B7800 Waterpump overheating problems

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earthwrks
Join Date: Dec 2003
Posts: 3853 Home Office in Flat Rock, Michigan
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2008-08-31          156430


Are you using well water in the radiator? Possibly sand is contaminating it and wiping out the seal. ....

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B7800 Waterpump overheating problems

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czrider
Join Date: Aug 2008
Posts: 7 jasper, georgia
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2008-08-31          156433


I really don't think my well water is the problem. I've run the same coolant mix in all my vehicles with no problems. My well water was not a factor with my first water pump; it failed before I replaced the factory coolant. I have to believe that this is just a strange coincidence. I am very meticulous when it comes to maintaining my equipment. Maybe the third time's the charm, and I will not have any more issues....I'll see after another 150 hours, I guess.
....

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B7800 Waterpump overheating problems

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czrider
Join Date: Aug 2008
Posts: 7 jasper, georgia
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2008-09-02          156439


I should also point out that the bearings on both waterpumps were still tight as a drum; no play what-so-ever when you grabbed & wiggled the the fan blade. It's almost like something in the coolant is eating up the seals. While my well water has been called into question, it was not a factor on the original pump, and has not harmed any of my other vehicles or equipment. ....

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B7800 Waterpump overheating problems

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earthwrks
Join Date: Dec 2003
Posts: 3853 Home Office in Flat Rock, Michigan
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-09-02          156440


As a homeowner I realize it seeming takes awhile to rack up 150 hours. Howvere as a business 150 hours would put you reaplcing a pump less than once a month--which no matter how you cut it is totally unacceptable.

Knock on wood, wit6h all the equipment I have or had, I have never replaced a water pump or alternator. Hydraulic pumps and batteries, yes.

Have you considered an over-the-counter coolant lubricant additive? Some coolants I have heard are actually abrasive since they have silica in them. ....

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B7800 Waterpump overheating problems

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kthompson
Join Date: Oct 2005
Posts: 5256 South Carolina
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2008-09-02          156442


Check your air filter as it will also cause your engine to run hot if it needs changing.

As to the seal and your well water, you could always run some into a large clear glass jar and let it set and see if there is sand in it. As to both pumps failing, is there any way sand or debris could be getting into the overflow bottle (I assume your's is like my B2710) or could the radiator cap not be sealing fully? kt ....

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B7800 Waterpump overheating problems

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earthwrks
Join Date: Dec 2003
Posts: 3853 Home Office in Flat Rock, Michigan
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-09-02          156453


Kenny raises a good point about the radiator cap but my thinking is from a different perspective.

Is it possible that both the thermostat AND the radiator cap are defective? I'm thinking that elevated temperatures from a bad stat combined with a cap that isn't relieving might be casui9ng excessive heat and pressure that the pump seal can't withstand. Or it is withstanding it but the increased pressure is causing premature wear. Just a thought. ....

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B7800 Waterpump overheating problems

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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
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2008-09-02          156454


If that water pump is belt driven could the pulley be bent, out of round or the mounting holes drilled a bit off-center? That might cause extra vibration that prematurely wears out the seal. ....

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B7800 Waterpump overheating problems

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czrider
Join Date: Aug 2008
Posts: 7 jasper, georgia
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2008-09-02          156461


Wow, lots of interseting theories as to the cause of my water pump woes! I'm certainly going to load 'er up with some sort of coolant lubricant this go-aroud; I'll also use the pre-mixed coolant just to take the well water out of the equation although I'm 99% sure the water is not the problem. Our area of North Georgia has the reputation of having very good water. Regarding an out of balance fan/pully assy, I don't think this is the culprit either; the B7800 uses a stamped steel pully, just like you find on your typical Japanese car (I used to be a Toyota Dealer mechainc in a former life). Considering the weight & construction of the pully, I don't see how it could be out of balance enough to cause my problem. Nothing is out of true or wobbling when the engine is running.
I also am nearly convinced that the tractor is not overheating until it has lost a significant portion of the coolant via a leaky water pump. I can't say for sure what happened the first time as my wife was running the tractor. Since that incident, I have been paranoid about a repeat occurrance, and have cleared chaff after every hour or so and watched the coolant level like a hawk. The tractor never overheated until I lost another waterpump, nad it didn't really overheat this time, the guage did not get into the red zone, just very close. When mowing, the temperature typically will get about about half way up on the guage before I clear the chaff, which immediately drops it back to around 1/4 of the way up. I also try to keep the air filter clean, which is quite a chore on a B7800; you can get a ton of dirt out of it after every job; I've run the same filter in my 2240 John Deere for years, in some fairly dusty conditions, I never get much more than a puff of dust when I blow it out.


atching the entire assy with the engine runningThe weight / construction of the pully

....

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B7800 Waterpump overheating problems

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Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
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2008-09-04          156492



Take a look at the pulley alignment to the water pump. I've not seen any problem with them at this time. You do have an unusual one. ....

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B7800 Waterpump overheating problems

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czrider
Join Date: Aug 2008
Posts: 7 jasper, georgia
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2008-09-04          156496


Art,

I took a look at my pulley alignment, and the alternator, waterpump and crankshaft pullys appear to be in perfect alignment. On a positive note, my dealer was very sympathetic and is replaceing my waterpump under warranty. Apparently there is a one year 'over the counter' warranty on parts. Even though it's been nearly 2 years since I purchased my replacement pump, the dealer is replaceing it under warranty anyway; mighty decent of him, I think.
I'm going to flush the cooling system, and drain all the old coolant from the block before installing the new pump. I don't have the new pump yet, my dealer had to order it; should be in Monday. Guess I'll have to wait another couple of years to see if this fixes things for good. ....

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B7800 Waterpump overheating problems

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kthompson
Join Date: Oct 2005
Posts: 5256 South Carolina
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-09-05          156501


CZ, if you have not already flush the coolant system, see if you can catch it and check to see if there is anything in it that could be cutting the seals. Sounds like a fair dealer. kt ....

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B7800 Waterpump overheating problems

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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2008-09-05          156502


Quote:
Originally Posted by kthompson | view 156501
CZ, if you have not already flush the coolant system, see if you can catch it and check to see if there is anything in it that could be cutting the seals. Sounds like a fair dealer. kt


You know those labs that you can send an oil sample for analysis? I think some of them do coolant analysis too, and the results would be interesting. I'm a little leery of using automotive coolants in diesels and would recommend that you buy the Kubota stuff. ....

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