John Deere 755 4x4 overheating

[grouchybear]

I have a John Deere 755 4x4 I'm not sure what year it is, it has a three cylinder diesel ( Yanmar ), I have replaced the thermostat, radiator cap, had radiator rebuilt, flushed block, installed a temperature gauge thinking that the idiot light was bad, however it runs hotter than I think it should. Temp. gauge usually reads around 260 to 280 degrees, however it does not shut itself down. I shut it down and you can hear it boiling and antifreeze will run out the overflow hose, antifreeze is 50/50 mixture. It seems the design is very poor, directly in front of the radiator is the hydraulic oil cooler, than in front of that is the diesel fuel tank, it appears that only a few inched of the radiator is exposed, most of it is blocked by the cooler and fuel tank. I live in Arizona and it is usually 80 to 95 degrees when mowing, the mower is a 48" woods brush hog. I don't know what direction to go next to fix this problem any suggestions I would appreciate.

 

[grouchybear]

Would appreciate quick reply.

 

[kencunningham]

Maybe the impeller on the water pump is worn?

 

[grouchybear]

Thank you for your reply, I did remove the water pump and it seemed ok.

 

[V1Rotate]

I assume that the radiator fan is in good condition and that the belt is tight. How about the head gasket? Did this overheating problem suddenly occur or did it start to happen gradually? A bad head gasket can leak hot exhaust gases into the cooling system making it overheat. Does the coolant look dark or have an "exhaust" smell? Does the engine oil have any coolant in it?

 

[project_X]

I have a John Deere 755 4x4 I'm not sure what year it is, it has a three cylinder diesel ( Yanmar ), I have replaced the thermostat, radiator cap, had radiator rebuilt, flushed block, installed a temperature gauge thinking that the idiot light was bad, however it runs hotter than I think it should. Temp. gauge usually reads around 260 to 280 degrees, however it does not shut itself down. I shut it down and you can hear it boiling and antifreeze will run out the overflow hose, antifreeze is 50/50 mixture. It seems the design is very poor, directly in front of the radiator is the hydraulic oil cooler, than in front of that is the diesel fuel tank, it appears that only a few inched of the radiator is exposed, most of it is blocked by the cooler and fuel tank. I live in Arizona and it is usually 80 to 95 degrees when mowing, the mower is a 48" woods brush hog. I don't know what direction to go next to fix this problem any suggestions I would appreciate.

Definitely water pump. My Yanmar 1602D has the same engine, in 90+ weather, I can usually mow for no more than 4hrs with out my temp warning light coming on. The problem is, I don't have a water pump. With a functioning water pump, I would expect to not overheat....

 

[grouchybear]

I checked the antifreeze is nice and green, there is no water in the oil, water level is full and there is no milk coloration in the oil indicating water in oil.

 

[grouchybear]

Definitely water pump. My Yanmar 1602D has the same engine, in 90+ weather, I can usually mow for no more than 4hrs with out my temp warning light coming on. The problem is, I don't have a water pump. With a functioning water pump, I would expect to not overheat....[/QUOTE.Water pump is fine I checked it and it functions as it should.

 

[kebo]

Is it possible a water hose might have a blockage or restriction in it??? If that's ok, it sounds like you have checked and eliminated just about everything else it could be. So, maybe it's not getting enough cool airflow?? Would it be possible to supplement airflow with a temporary electric fan to see if that helped any?? You can probably pick up a small 12vdc fan fairly cheap at just about any junkyard to try one and see.

 

[dieselscout80]

Is a hose collapsing and restricting coolant flow (lower hose on radiator)?