850 with 3 point problem

[lilburr]

As mentioned yesterday, I cranked the 850 and Idled at 1250RPM with the cap off, hoping to 'burp' the air outta the system. This is the only theory Ive got with this running hot and spewing coolant deal Ive got. Idled more than 30 minutes, maybe 45 or 50 minutes and coolant level would move up and down, sometimes pushing coolant outta the radiator, sometimes dropping into the radiator. At one point, I added 2 - 3 quarts of coolant and then it resumed with the rising and dropping, temp gauge never registering a movement off bottom end (while under no pressure). After quite a while (above), I replaced rad cap and idled it up and rode around in a quick loop to re-place it in barn. By the time i was half-way thru this move, temp gauge was up to ~190 mark and when I pulled in and killed the engine, it popped up to ~220, and cooled from there. Steam was escaping from the cap area; it was heated up.

Any more ideas would be helpful. So far, I have tried pretty much all suggestions but it seems that extended worktimes will overheat this unit.

 

[wolftree]

List all that you have done or replaced on the cooling system thus far.

Is the radiator copper or aluminum?

 

[lilburr]

Thermostat replaced (160), flush (twice), and antifreeze (twice). I dont know but me thinks aluminum. On inspection, hoses appear almost new (paper wrappings still fresh).

 

[wolftree]

I would take the cheap route and replace the radiator cap first. Second really look the radiator hoses over, both of them.

Scrape a small area on the radiator, if silver color, then it is aluminum. Copper radiator will be goldish in color. I expect yours is aluminum. Copper can be boiled out

 

[lilburr]

oops, forgot... new cap too. wolf, it seems that the rad is clear, when pressing on upper or lower hose, level of coolant will visibly rise or fall.

 

[Henri88]

I ask the question before but did not get an answer. Did you replace the cap with the same spec as the old one or did you look up what was recommended for your tractor.

 

[dwellonrooftop]

Maybe your water pump is going out. Sometimes you can wiggle the fan blade.

 

[wolftree]

lilburr,

That says nothing is broken. That now only leaves something not working quite up to specification.

Have you looked at the hoses as it is overheating? A wore out hose will collapse, then restrict water flow. There may be no visible appearance from outside of the hose while cold.

I assume you blew through the radiator fins from the engine side with compressed air. Spraying water does not always get everything unless it is very high pressure.

There is a small chance that the water pump is not moving the water sufficiently (worn out pump). Try wiggling the shaft of water pump, it should not wiggle.

If all of these things checkout, then that leaves only the radiator and 20 years of built up scale deposits in the tubes. You can try running radiator flush for longer periods of time in hopes of removing more deposits.

 

[Bailout]

My vote is for a new water pump... My 750 did the same thing - the fan was loose and after a several hour pump change, it's run perfect for years now...

Brian

 

[jd110]

Another possibility that no one has mentioned is a bad head gasket or cracked head. Hate to suggest major problem, but it is a real possibility with the symptoms you have.

 

[lilburr]

An update on my 850 and overheating. For a couple months there, I was distracted with other life stuff so I got back to it just the other day.

A friend came over to observe and advise, a young gentleman that Ive known since he was born and sorta in the business, also the friend that I had accompany me when shopping for the tractor.

Anyway, we had a starting problem right off the bat. Took it off had it tested was bad and we replaced with a re-manufactured starter and the clicking (no start) problem was over ! Starts on the first bump now.

We still were battling the overheating and after going thru everything included in this thread, we checked the belt. It was mentioned early in this thread and I visually checked but did not think it was faulty. Turns out that my 850 would do adequately while 'puttin' around at 1500 or so rpm but when putting a strain on the motor for more power, it would overheat and spew coolant. Well, the belt was slipping at higher rpm and not spinning the water pump and distributing coolant thru the system !

Went to the parts store and got a belt 1/2" shorter and installed. So far, the tractor is running 100% and I've yet to approach overheating (according to gauge and visual), even after shutting down.

I'm still in the testing stage and have not really hadda chance to bear down but initial results are very encouraging; no major damages or further worry about motor damage.

Thank you to all suggestions - it has been all very accurate in the diagnosis and fix to my little 850 and now I'm gonna clean up the area as planned and find out what this piece can do. My driveway and barnyard looks better than in 20 years and this after our coldest worst weather in memory.

I'm pretty sure we'll discuss more in the future ...

 

[Henri88]

This is good news. Fingers cross! Thanks for the update. :thumbsup:

 

[lilburr]

OK, got a 5' boxblade yesterday and boy is it 'light', we'll see how long this implement will last (as built). Seems they just dont make 'em like they used to. I haven't done any work with it yet.

 

[lilburr]

as much as I hate to report, my 850 spewed coolant yesterday and overheated while working it. Seems like coolant never really circulates thru the system as the gauge (and radiator) cooled quite quickly but the block was hot and slow to cool. I think next step is pull the thermostat (I reckon).

 

[lilburr]

Over two years have passed since I started this story, the 850 has been barn kept but ignored, drained of all motor fluids and covered with dust.

So I got some time and I need this space in my barn. This tractor had an overheating problem and I had been ignoring the blown head gasket solutions and trying to make certain the coolant system was functional.

I have determined thru the pressure check that it was probably the head gasket and started dis-assembly. Surprisingly an easy and simple procedure (so far). and guess what I found ? The shadetree that must've worked on this unit before my purchase replaced the head gasket too and IT WAS INSTALLED BACKWARDS, BLOCKING THE TWO WATER PORTS AT THE REAR OF THE BLOCK !!

Fortunately, I don't believe I over-heated it to the point of damage and after cleaning up and order of most logical parts like gaskets, crush washers, ect, I am real close to reassembly and testing. I did not replace waterpump as it appears nice and tight and in good shape.

This little project is not completed yet and I can't give an end report but I have picked it up and I will report on final findings. The overheating problem since day one of my ownership may have been diagnosed and addressed but in my research, I have heard that these 2610 yanmar motors have a overheating problem and head gaskets may be the number one deal with them. Anybody else ?

i'll try to remember camera for photos, the project is 20 miles from this computer but I am encouraged to the point of reply here. (hope it's not too early)

I reckon my most important finding in this is WATCH WHAT YOU'RE DOING OUT THERE and double check. This head gasket is NOT REVERSIBLE and has a front and a back.