Yanmar Tractor Tf 85 Lm Who Knows How The Cooling System Works?

[sreiter]

Hi all, is there anybody who can help?

My wife's father has above mentioned 2 wheel tractor, now 14 years old. It overheated yesterday and I try to find out why.

The tractor has a water cooler that sits directly on top of the engine block. I can not find any hoses (except to the expansion tank) or a water pump attached. The fan is in working order. Has anybody dismanteled an engine like this before? I suppose there is a water pump somewhere which might not work, does it sit inside the engine housing (under the radiator?) I would be very surprised if the water ist just gravity-circulating. Otherwise of course the water bores might be full with dirt and water is not circulating- any suggestions for a remedy? We are in the sticks, I would not know how to get the thing to the nearest dealer. So- help would be appreciated! Cheerio Stefan

[Maizefarmer]

It could be one of several things - but start off by elminating this one problem: fill it up with water and let the engine run till it is hot - what is happening to the water? - is it, for lack of a better word "dissappearing" and you are having to refill it, and if this is happening, what happens when you refill it? - does it all dissappear again?

The whole "dissappearing" process, once the engine has warmed up, should not take any more than around 2 - 5 minutes or so.

Is this what is happening - or do you find that despite over heating the water is still present and you are not having to refill?

Thats the first thing we want to establish - is the water dissappearing - or not?

Also come back with an answer to this: once things have cooled down take a close look at about 250ml or so of oil taken from the engine oil drainage. What does it look like? - has it lost the translucent appearance that oil usualy has, to be replaced with a cloudy brownish appearance?

And thirdly, what colour is the gunge that collects underneath the oil filler cap - we are looking for a brownish appearance?

The 3 points collectively amount to one of 2 possible problems:

1) blown head gasket

2) or a stuck thermostat (its not opening which is causing the water to run into the block, stay there and boil off).

Lets eliminate this - then we can look at other things.

As far as the water pump its self is concerned: extremely well designed and very very durable - I doubt it very much. It may be the ceramic washer in the mechanical seal (on the water pump drive shaft) - but you'd be reporting to us a re-peatative click of cyclic noise (in sequence with engine rpm), and the water loss (would be very slow). They are also gear driven - and if a tooth or teeth had broken off (which I have never seen happen with these engines) you'd be hearing a repetative knock or loud click each time that section of the tooth/gear turned and failed to engage with its other half.

To answer your question - yes, its in the engine block at the front: the pump cover can be removed by removing 3 or 4 bolts. Once it is off the impellar can be pulled out on its shaft - if you want to dismantle it, when removing the impellar do so slowly: the mehcanical seal is spring loaded can can push the washers and itself off suddenly: you are looking for 2 things:

1) broken/damaged impellar - and that I also have never seen on these engines.

2) abnormal/ecentric wear around the the impeller shaft - that I have seen, and will happen if the engine is run for an extended period with no water.

We can deal with these, and other possible causes later - lets get the head gasket and thermostat out the way (the 2 most common causes to over heating on these blocks).

Edited December 21, 2008 by Maizefarmer

[sreiter]

Hi Maizefarmer Yours is a very thorough reply, thank you so much. May be naively I had assumed that it was more likely to get a blown head gasket from overheating and not the other way around, but you are right, I should have done a few basic checks first. The tractor is old and in a bad state of maintenance, so everything is possible. But I agree that especially the thermostat (that I had been looking for in vain) is a likely candidate....Unfortunately I found a big leak in the diesel tank when I removed it, an old repair had cracked again and there are new holes next to it. I have to find some way to use it temporarily to start up the tractor for tests. The garage in the next town has a party today and tomorrow, no help from there. I also might have to shoot off to Laos first and try to sort my visa issues. So what I am trying to say is that it might be some time before I can report further progress! Thank you again Stefan

[Maizefarmer]

Thats fine, I'm on holiday in any case - one of the 2 oppurtunities I get each year to get away with the other half, my daughter and son - so deal with it in your own time.

Yer, "maintanence" ............ where have I heard that before in Thailand!!!! - mind you, I've seen engines running in Thailand that I would never dreamed in a thousand years could turn over, let alone run!

Once they start playing up on issues like thermal efficiency (especially if old) they've generally had it, their torque drops like a stone and you can look forward to a continous list of ongoing maintanence issues. The question you have to ask yourself is, is it worth throwing more money at it. I am going to take a guess and say, no - its reached the end of the line. I'd be suprized if its producing any more than 40% - 50% of its rated torque (these engines have a performance curve that is all about torque - their hp output is laughable - but thats their design), and short of a block rebuild its perhaps time you invested in a new one. I would (personal opinion)

If you do replace it, get a new or low hour Kubota RM or RT 90 - they are both exactly the same size, have the same rpm/torque ratio (give or take a few turns), have the same mounting dimensions (i.e. if you have a 2-wheel tractor frame that bolts directly to a TF85LM or HM, then the Kubota 90 block will bolt straight in/on as well) - and the 90 produces more power, more torque while consuming less fuel.

[sreiter]

Hello Maizefarmer! Have a good holiday, I am sure youdeserve it.

Maintenance, eh- what a topic! A friend of mine once said the difference between a third world and an industrial country was the lack or presence of maintenance. Hence he declared his own country a third world country. He was speaking about the UK and we were sitting in a train to London that had just roken down......So- it's not only Thailand. Thanks for the Kubota info-I had a look already before and guessed it would fit. They give some money on the return of the old tractor. However, we have other big problems right now (my wife's mother broke her spine in a nasty motorbike crash) and we are pretty broke. So- I still hope I can get the old thing running a bit longer.

Talking of which: Neither you nor I have thought of the very first basic thing: I opened the oild drain to have a look at possible water in the oil (there in none)--but there also was no oil. Well, there was a litttle bit of something you could have tared the road between here and Bangkok with, but I would not like to call it oil. So- that definitely was already the first reason for the engine to become too hot. Remains to be seen if that has dammaged the head gasket. I filled the engine with some diesel and cranked it around for a while, leaving the diesel soak in, did the same again and drained it in the end, just to remove as much as possible of the tar. Eventually I filled it with new oil, but I think (should the engine be OK) it should be changed again after a few hours of running. We somehow used the old tank for a try to start the engine and managed this way to run the engine for a few minutes. The water stayed at level, but the time we had was too short to see what happens when the thing gets hot. Now the tank is in for repair.....--to be continued tomorrow I hope! Best wishes,a good Christmans and a good holiday again Stefan

Just in case you should not be able to read the forum on holidays-and I find out the thermostat is not working- is that sitting behind the front cover as well?? All the best Stefan

[kenk3z]

Does your engine look something like this?

http://www.yanmar.co.jp/yasc/products/indu...172361_480.html

I notice that there are two cooling options for these smaller diesel engines. You can have a "hopper" and you can have a "radiator". We are all pretty familiar with radiators because of larger tractors and automobiles.

For my part, I had never really heard of a "hopper" configuration and did some research. I found this:

http://www.utterpower.com/cooling.htm

Apparently hopper systems remove heat by boiling away the water supply as steam. So if you have nothing that looks like a radiator, then you may have this hopper system.

I suppose what can happen over time with hard water (lots of minerals) is that the system gets clogged up with mineral deposits and the cooling efficiency goes way down. So there might be something you need to get cleaned somehow, perhaps with a weak acid solution in the water.

Hope this helps.

kenk3z

[Maizefarmer]

Hello Maizefarmer! Have a good holiday, I am sure youdeserve it.

Maintenance, eh- what a topic! A friend of mine once said the difference between a third world and an industrial country was the lack or presence of maintenance. Hence he declared his own country a third world country. He was speaking about the UK and we were sitting in a train to London that had just roken down......So- it's not only Thailand. Thanks for the Kubota info-I had a look already before and guessed it would fit. They give some money on the return of the old tractor. However, we have other big problems right now (my wife's mother broke her spine in a nasty motorbike crash) and we are pretty broke. So- I still hope I can get the old thing running a bit longer.

Talking of which: Neither you nor I have thought of the very first basic thing: I opened the oild drain to have a look at possible water in the oil (there in none)--but there also was no oil. Well, there was a litttle bit of something you could have tared the road between here and Bangkok with, but I would not like to call it oil. So- that definitely was already the first reason for the engine to become too hot. Remains to be seen if that has dammaged the head gasket. I filled the engine with some diesel and cranked it around for a while, leaving the diesel soak in, did the same again and drained it in the end, just to remove as much as possible of the tar. Eventually I filled it with new oil, but I think (should the engine be OK) it should be changed again after a few hours of running. We somehow used the old tank for a try to start the engine and managed this way to run the engine for a few minutes. The water stayed at level, but the time we had was too short to see what happens when the thing gets hot. Now the tank is in for repair.....--to be continued tomorrow I hope! Best wishes,a good Christmans and a good holiday again Stefan

Just in case you should not be able to read the forum on holidays-and I find out the thermostat is not working- is that sitting behind the front cover as well?? All the best Stefan

Apologies for the delay - have been getting ready to return home (always more stuff to bring back than you leave with!!!)

Anyhow - back to the subject...............reading between the lines of what you have said, my take on the state of this "iron horse"(?). Time for the knackers yard. Sounds like you may well be able to sort out the problem, but from the state of wear & tear your description leaves me with, it will shortly be followed by another problem, then another and then another.....

Flush the engine out with some warm clean oil - any cheap low viscosity oil (the lower the viscoisty the better) - let it settle in a glass bowl/jug of sorts for about an hour or so - get a small school type magnet on some string and "jig" it around what ever has settled on the bottom of the jug.

Rinse the magnet off in some clean petrol/meths/alcohol - bet youre going to find a load of metal slivers/shavings lying in the petrol/meths/alcohol. That will be your con-rod big or small end (and also the crank) - not valve train (bits from the valve train end to settle out in recesses at the top end part of the block with these engines)

From the "past maintanance" picture you notes have painted, this block has reached that stage - and quite frankly, its the point at which you start throwing good money at bad.

Pension it off and get a new unit - or low hour used unit - and then educate someone to follow through on a disciplined maintainance schedule.

[sreiter]

Hello Maizefarmer and kenk (yes, the tractor has a radiator!)!

Again thanks for reply and tips! We had a sackload of other problems to attend to, so I had to cut it short!

1. We found a local guy that welded a new bottom on the old tank (great work, he said it took him 5 or 6 hours). The weld is tight (for now) and the price was 300 Baht.

2. I flushed the engine with diesel several times and let it soak. After draining (a loooong time) I refilled the engine with oil and off we went for a test spin- it started OK, runs OK, sounds OK and does not overheat under load. Amazing- and I pull my hat to the sturdiness of those engines! For me and for now that is as good as it gets- it might buy us time to next year or even longer. All the best to your enterprises, we will surely be in touch int he future! Best of luck, happy New Year Stefan

[Lickey]

Private owners of British Leyland Sherpa vans used to come back to the workshop and ask"did you change the oil? its still as black as the ace of spades!!"

The B series leyland 1.8 diesel was never a hot runner, the oil would drip out of the sump for an hour or so, and still leave a black sludge inside the motor, so we would drain a pint or so, then add a pint of Saftey Kleen fluid, normally used in the parts cleaning tub, then take the van round the block and drain it, all the crap would fall out and doing the nice clean tappets were a joy.

This was at a time turbos were becoming popular, with hotter lube efficiencies needed and thrifty managers always bought the oil the rep said would do both,normal and turboed, so its a good idea to follow the manufacturs Rec Spec for oil and filters ect.

I really dont know your engine but the thermostat should be in the engine at the end of the top hose from the rad,ive known some stats mounted on the back of the head, although on a V16 british built Dorman gen set, they are hidden in the top hoses in an alloy tube.

If you are not mechanically minded Stefan, you have done well so far, Good luck with the old tractor, cheers Lickey..

[sreiter]

Hi Lickey Enjoyed the sherpa story, thank you for the flowers too! Reminded me somehow of my old Morris Minor, no diesel of course though! Managed there once to clean the rather clogged up water cooling bores in the engine using H2o2- once the engine was really dry inside- worked very well. Those yanmar diesels are interesting engines- the radiator sits straight on the engine housing- no rubber hoses at all anywhere in sight. Guess there are metal tubes or bores from the bottom of the rad running straight to the parts to be cooled. The thermostat is somewhere in the engine housing as well. However that might be- for now the tractor runs, the oil being still black as the ace of spades. We are in Bangkok trying to find he right hospital for me, time for some body repair! No more time for the tractor right now! Good luck and thanks Stefan