Overheating

[BurningBushFarm]

I can't find the post I thought I just posted.

Bush hogged today. Fun.

Problem: Temp light came on after about 20 minutes.

Before going out we had cleaned the screen in front of the radiator, blew out the air filter, and the level of the radiator water was fine.

Came back inside and checked the manual and this forum.

Will check flow @1500 rpm. Will flush it out.

Any other suggestions?

Thanks.

 

[adjusterr]

If what you do doesn't work, check the thermostat. The temp light will have a sending unit, that might be bad. Does the engine seem hot or is the red light simply on?

 

[California]

If the overheating is real you may notice a burned smell. Don't open the radiator cap, that's the same as opening a pressure cooker! The top of the radiator shouldn't be to hot to touch for a moment unless you were running it real hard.

Incidentally these need to be run at good speed, over 1800 rpm or preferably over 2000 to circulate coolant through the radiator when working hard. Pushing it hard at low rpm will cause overheating.

I bought this little Harbor Freight infrared thermometer on sale under $10. Various parts of the radiator and engine show different temperatures but I've never found the radiator over 200 or the engine head over 250 except maybe right at the exhaust manifold. This can verify if you simply have a bad warning light sensor.

This model Yanmar doesn't have a thermostat.

One test you can perform is: with the engine cold then mid-warm, look in the radiator for bubbles (engine running) which would indicate a head gasket leak (or less likely, cracked head). Exhaust leaking into the coolant will overheat it quickly. This might be accompanied by loss of coolant too, but not necessarily. You should see water circulating, showing that the water pump is ok, but not bubbles.

If there is any question of losing coolant be sure to spin the engine before starting using the compression release, to blow any water out of the cylinders since water is incompressible.

It isn't unusual for these 30 year old tractors to have a plugged radiator. A radiator shop can likely rod it out, or a new radiator should be under $300.

 

[BurningBushFarm]

I was making sure I was running at ~ 2400.

I was in 5th, but then went to 3rd the second time out after I read about making making sure I was moving enough coolant through the radiator.

If there is no thermostat what triggers the temp light?

Thanks for the Harbor Freight tip.

 

[California]

A thermostat is a temperature-sensitive valve just before the upper radiator hose that holds water in the engine until the set temperature, maybe 170 - 190. Then it opens to let the coolant reach the radiator. But these old Yanmars don't have one.

The warning light sensor is an electrical switch that closes around 235 degrees warning of imminent boil-over.

And the radiator cap is nearly identical to a pressure cooker regulator - it holds pressure until 13 lbs. This allows up to some 240 - 250 degrees coolant temperature, still liquid, before it boils and spits out the coolant. Engines run more efficiently at higher temperatures.

 

[normde2001]

You should post your model # on every thread. The YM2000 runs notoriously cool, about 160*, and with all things right, should never overheat.
I have a Ym2000B, with a factory temp gauge, and the first tool to go in my toolbox was a whisk broom. When mowing, as soon as I see any rise above normal on the gauge I know it is time to clean the rad screen. It normally never reaches the 1/4 mark.

 

[MikeInEburg]

After years of brush mowing, the actual passages thru the radiator can become plugged. Even though we have the same debris screen, every five years or so I have to remove the radiator from the tractor and carefully hose out all passages. Huge difference.
Mike

 

[clemsonfor]

If what you do doesn't work, check the thermostat. The temp light will have a sending unit, that might be bad. Does the engine seem hot or is the red light simply on?

Have not read all posts so forgive me if i repost this.

Your tractor does not have a thermostat.

 

[clemsonfor]

You have a problem, there is no reason to overheat at this temperature unless you have an issue. I would second a head gasket proble, maybe, or most likely a blocked radiator which basically means that only part of it will be cooling right with correct flow. Another thing is make sure your belt is not slipping, it needs to turn the same speed as the crank pully not be slipping causing the waterpump to turn at a slower speed.

 

[Argosy]

Your tractor does not have a thermostat.

Does it have a water pump or convective flow? That will make a lot of difference in how to operate it.

 

[clemsonfor]

Does it have a water pump or convective flow? That will make a lot of difference in how to operate it.

She has a YM 2000. It should have a water pump on it. I say should cause im assuming it is still the way the factory designed it, which was with a waterpump. I doubt this is a frenkienstein tractor but if it was it may have an older motor or smaller motor in it.

 

[BurningBushFarm]

YM2000D (Just bought about a month ago.)

Has a water pump.

Hubby checked fan belt (in addition to another things done above.)

Previous owner did not mow hardly at all (used it to grade his road ). Bush hog was used twice ... maybe three times. We have air hose so have blown radiator out, cleaned screen.

Biggy is coolant needs to be changed and radiator flushed. (For a meticulous guy [previous owner] we were surprised at status of coolant.)

No signs of head gasket problem seen so far.

Check back with you later.

Thanks.

 

[BurningBushFarm]

Not a frankenstein --

Still has the Japanese labels on it as previous owner elecected not to have it repainted after he picked it out of a line up of newly imported gray tractors back when Corriher guys in Newton, NC were selling them (10+ years back).

Apparently he was first US owner.

 

[California]

I found my post describing readings from the Harbor Freight infrared thermometer.

This was right after mowing:

140 degrees on the bottom of the oil pan, 165 at the lower block, and 195 near the injectors, at the upper radiator hose fitting, and at the radiator upper tank. The radiator lower tank was below 100.

Others have commented that a radiator shop's pro infrared gauge is more accurate, so let's say this cheap one is just a rough diagnostic tool.

 

[6thgpSF]

does your coolant bottle have fluid in it ,sometimes that will cause the light to go on,also check oil level.this can be an indication of bad HG. russ

 

[clemsonfor]

These radiators are pretty muddy and gunky. Its mostly from the previous life in japan that most of us conclude that straight rice field ditch water was used then drained in winter to keep the block and radiator from cracking. This is evident in the sediment that looks like reddish musd that has come out of many tractors including mine in a fine dillution that will settle out when coolant is left in a jug. The 2 radiators with cracks in them that i got when i first got mine are also signs of weak or no antifreeze. the block has this mud in it so unless you flush it real good it will have it still in the system. Its possible that the guy changed it when he got it and never did it again and the running it over the years loosened some crud each time. Just guessing though i have no idea what my farmer did with my tractor or yours 25 yrs ago!

 

[California]

The radiator in my US-model Yanmar had been professionally rodded out (cleaned internally) just before I bought it. I was told the tractor was in occasional light use for many years just for the loader. Then the second owner started to fix it up for heavy use discing an orchard. But after spending money on the radiator and hoses, and a starter, he said it was too light to pull his disc. I bought it at that point.

So the history of US good-ol-boy maintenance on mine wasn't any better than the rice paddy Yanmars.

Flushing it now (after the second then the sixth year) the coolant comes out clean. I'm convinced that professional cleaning was worth it.

 

[Car Doc]

I agree on the ir temp gun mainly because you have no way to check the calibration of your sender and I would add also that the fan belt needs to be tight enough.

Yes I know it sounds redundant but that fan puts a lot of load on the little belt and if its at the end of adjustment it may just need that little extra.

Fan belts are no fun on these tractors to change since the lower hose has to come off just saying that may why its slipping if it is. hth :thumbsup:

 

[BurningBushFarm]

Well I have been out and mowed/bush hogged a couple times since the last posting. I have 4 acres of hayfield that I am cutting dead weeds (mostly broom sage) down on in preparation for spring, and another 2 acres of pasture taken over by broom sage.

Bought the little IR thermometer. Great idea.

Observations:

First of all most of what I am cutting is thick broom sage, 3' tall. For those of you who don't know, its seed are like furry feathers. So cleaning the screen every two passes is necessary. I tied a little brush on my fender.

I blow out the radiator when I get back.

We have drained the brown radiator fluid, refilled and drained again. Flushed w commercial stuff, refilled and drained again. It's still brown, of course, but maybe not quite as brown.

When I stop to clean the screen I have checked the temps. I think I have located the hottest part of my radiator, which seems to be the outside angle side by the upper hose. One time I did get a 200 degree reading (after I kept mowing) but usually it is 180s-90 over there. The other "high" readings tend to be 160s-180s. So I haven't overheated, actually.

My temp light goes on before the readings got to the highest, so we are thinking there is a problem with the sending unit. I notice Hoye only sells them for use with the gauge. (We were thinking it might be dirty, or something.) We might spring for a gauge sometime in the future, they are not expensive.

But then the other reality is the radiator probably could use a professional cleaning. The first US owner bought this about 12 years ago, and did not mention doing that, and I am pretty sure when it came from Japan they didn't bother.

The idea that they refilled them with paddy water is interesting since it seems most people have the excessively brown water which doesn't go away with radiator flush or multiple water flushes, mmm?

So I do not think the radiator is overheating, (but OTOH I don't think I am really pushing it) but I like gauges, not idiot lights, as I have a better sense of what my limits are.

I drove a 20+ year old Ford van across the country (Yosemite and desert and all) and back one summer (110 in Needles) with no air conditioning. Fords were notorious for having undersized radiators back then... and by watching my temp gauge we managed just fine, with only a couple times we actually had to stop and wait for a cool down. (The long incline going south into LA.)

So somewhere in my future is a professional flush and clean ("rodding?") and a gauge. In the meantime I'll get the feel of how long I can bush hog without "overheating."

So here's another question: What percentage of anti-freeze?

Right now the tractor is in my husband's slot in the garage (mine is full of moving and horse cr*p -- isn't he great?) and our temps have been unusually warm (thanks Al), but I have seen everything from 10% to 40% mix on antifreeze.

Input appreciated.

Thanks guys!:thumbsup:

 

[BurningBushFarm]

Hey -- I just scrolled down below this discussion and found this:

Overheating Information

http://www.tractorbynet.com/forums/yanmar/105515-overheating-information.html

On the Yanmar forum no less. (Didn't pick it up in my searches ...)

I hadn't thought there was anything useful below the comments/discussion. Wrong.

So yeah, radiator needs an "Intervention.":laughing: