The temperature light on my ym240 2 cylinder 1979 diesel has been going off after a short period of time (45min to one hour) after driving a john deere 48 inch rotary mower. I've been running the engine at about 1500 or so rpm. The minimum horsepower of the attatchment is 15. I started by draining and flushing the radiator fluid and am thinking of refilling it with an 80/20 mix of water to coolant. My next step would be to change the oil. My next step would be to check out the water pump impeller and see if it is faulty. Is there a thermostat on this machine. It seems logical that the temperature light is funtioning correctly. I just got this machine, and am hoping for the best. If anyone has any ideas please share.
The temperature light on my ym240
- Thread starter normvjr
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California
Super Star Member
- Joined
- Jan 22, 2004
- Messages
- 15,016
- Location
- An hour north of San Francisco
- Tractor
- Yanmar YM240 Yanmar YM186D
The previous owner of mine had taken the radiator in and had it rodded out. With a good radiator (and water pump) it is impossible to trigger the light until the radiator screen is blocked solid with mowing chaff. I don't recall that I've ever seen the light after I learned that cleaning the screen is a routine maintenance item.
Does yours have that screen in front of the radiator? It would be easy to make one from window screen if needed.
I suggest run a garden hose, and maybe some compressed air *carefully* applied, through the radiator from the fan side toward the front until water passes through it easily.
If it still gets hot it could need a water pump rebuild, or it might need a head gasket. Start it from cold and let it warm with the radiator cap off. Watch in the radiator for bubbles (exhaust) and good circulation (water pump).
There isn't a themostat.
You noted 1500 rpm. It sounds like it will fly apart but really, you need to mow with the engine at PTO rpm (2200) to let the cooling system work as designed.
Does yours have that screen in front of the radiator? It would be easy to make one from window screen if needed.
I suggest run a garden hose, and maybe some compressed air *carefully* applied, through the radiator from the fan side toward the front until water passes through it easily.
If it still gets hot it could need a water pump rebuild, or it might need a head gasket. Start it from cold and let it warm with the radiator cap off. Watch in the radiator for bubbles (exhaust) and good circulation (water pump).
There isn't a themostat.
You noted 1500 rpm. It sounds like it will fly apart but really, you need to mow with the engine at PTO rpm (2200) to let the cooling system work as designed.
Ditto on working it at 2000-2200 RPM. 80/20 is a good warm weather mix, but it should not overheat even with 50/50 if everything is working properly. You can watch the coolant circulate if the pump is working properly (stay very, very clear of all moving parts and always have someone in the operator seat). Bubbles/air blowing into your coolant reservoir is a sure sign of a bad head gasket. One thing we have learned is that more of these units have some degree of radiator blockage than we ever used to imagine. Some can be cleaned......and some can't. There are aftermarket radiators now. They aren't cheap, but neither are they expensive, and you might be shocked at the difference it can make.
California
Super Star Member
- Joined
- Jan 22, 2004
- Messages
- 15,016
- Location
- An hour north of San Francisco
- Tractor
- Yanmar YM240 Yanmar YM186D
I thought I maintained my old Trooper adequately but after 15 years it began to run hot. The shop used a remote thermometer that looked like a timing light, and discovered that 1/4 of the radiator was blocked.LMTC said:
In the current Harbor Freight mailer I see a 'Pocket Non-Contact Thermometer' #93983 for $9.95. I would buy one, if I needed to diagnose a suspected a plugged radiator.
California said:
The temperature "gun" is very helpful, and you can get one that is quite adequate for this work for around $75. Measures average temp over something like 1" at a foot, spot gets bigger as you back away. Dyno the tractor until it's very warm, then shoot the radiator in sections.....if there is significant variance over sections, it is plugged. I use ours on the grill....steaks are so much better when they hit the grill properly hot, and I "shoot" the cast iron grate on our charcoal grill and put them on when it hits 700*. Great for checking AC temps out of the vehicle vent, etc. We played with ours a bunch when we first got one. Hmmm..exactly how hot IS that sidewalk?
Jagmandave
Veteran Member
Could be a bad sensor for the light, there's been quite a bit of discussion about that here lately. A new sensor is way cheaper than a new radiator, but I would do as the others have suggested and make sure there's nothing blocking it too.
