Yanmar YM240D OVERHEATING

Bugyman · Jul 27, 2006

Hello from a newby! New to this forum and new to diesel. I bought this tractor (YM240 D) from a co-worker who is from California and was not acustomed to Kansas winters. He neglected to check the antifreese and the water jacket got a nasty crack which he repaired with J-B Weld about 3 times over about 7 years. he just re-did it this spring although it leaks just a little now. Now he told me that it over heats after mowing 20 min. but I put a mech. temp. gauge in it and it climbs to 140 in 20 min. without stresing the engine. I ran a flush and refilled the coolan, and cleaned out the radiator fins but still hot. Can't find a thermostat (does this tractor have one?) I can tell the coolant is circulating. Now I took off the air cleaner lid while runing and can feel air puffing out the intake, bad valves? tractor has decent power (I juess) it fires right up every time, and runs smooth.

bruce1966us · Jul 27, 2006

That tractor will run up to 232F before it is considered to be overheating.

Gizmo36 · Jul 27, 2006

If the Light is coming on get you a new Temperature sending unit. that will fix it.

Bugyman · Jul 28, 2006

Gizmo36 said:
If the Light is coming on get you a new Temperature sending unit. that will fix it.

I took the sending unit out to install the mechanical temp gauge, which I belive is a much better indicator.

normde2001 · Jul 28, 2006

This is confusing, are you saying 140 degrees is hot?(is that celsius or American?)...no thermostat. There are too many good tractors out there to buy one with a cracked block.

Bugyman · Jul 28, 2006

Well, he has used it (maybe not worked it hard) for years with the crack. And I got it with the brush hog and box blade for $1200. Any way, youre saying it has no thermostat?

normde2001 · Jul 28, 2006

No thermostat

justanotherjoe · Aug 5, 2006

Bugyman- My 240D has a small crack in the block behind the starter. Bought it that way for $1800, money back guarantee. That was 1500 operating hours ago. Mine runs cooler on all water with some additive, no antifreeze.
With that extra air source in the block, I had a lot of rust. After treatment and thoroughly flushing the block, had the radiator re-done and no problems since then.
Over a 20 year period in no-freeze California, think how much water could be evaporated/distilled out of a radiator on a diesel engine. All the dissolved minerals stay in the unit, what evaporates is pure water.

normde2001 · Aug 6, 2006

justanotherjoe said:
Bugyman- My 240D has a small crack in the block behind the starter. Bought it that way for $1800, money back guarantee. That was 1500 operating hours ago. Mine runs cooler on all water with some additive, no antifreeze.
With that extra air source in the block, I had a lot of rust. After treatment and thoroughly flushing the block, had the radiator re-done and no problems since then.
Over a 20 year period in no-freeze California, think how much water could be evaporated/distilled out of a radiator on a diesel engine. All the dissolved minerals stay in the unit, what evaporates is pure water.

You should be using 50/50 mix of distilled water and aintfreeze in your radiator.

Bugyman · Oct 23, 2006

Well i'm back, seems i've got way too many irons on the fire any-hoo first let me say that after reading my previous post i must have had a brain fart its running 240+ not 140. Ive been running it till it heats up then letting it cool down trying to get some nesesary work done (hopefully I havnt harmed it) now i've brought it home and torn into it expecting to find the water jacket pluged up (previous owner used that powdered metal "stop leak" when the J-B weld would start leaking) but only found rust and rust scale piled in the low areas. the head gasket looked good, but with all the over heating i'm going to take the head to be checked for warping. Im also takeing the radiator to be cleaned out. Now, anyone jot any ideas on how to thourly clean out the block? also howabout welding up the block, can it be done?