[pjwoodworker]

A long story with a question or two. I was mowing with a 60" deck on my JD 445 and noticed the engine temp gauge was very near the red. Quickly went to the shed, let it cool off a couple of hours. The radiator overflow reservoir had what appeared to be sufficient water in it but I filled it all the way to the top anyway. Started mowing again. It got hot again; after just a short time. Let it cool over night. looked in the radiator; could see the coils with no water over them; even though the reservoir was still full. Filled the radiator and mowed again. Seemed to be okay but as I closely watched the temp gauge, it was fairly constant at about 30% of the way from cool to hot. But occasionally the temp would quickly climb to about 50% for just a few seconds; then drop back to the 30% level. Is this normal? Is there something possibly wrong? The air temp on that second day of mowing was very cool, about 60 and I only mowed for 30 min. max. Thanks.

 

[Diesel Powered]

That coolant had to go somewhere. Have you had this tractor very long? How many hours are on it? Look for leaks around the end caps on the radiator, both ends of both radiator hoses, the bottom of the water pump, and everywhere in between. There should be a full line on the overflow bottle and the level shouldn't be above that; the radiator will generally only pull coolant in from the overflow tank as the engine cools down after you shut the tractor off (pending there isn't a leak in the system).

 

[jd3x]

Try changing the thermostat. My 425 had the same problem.

 

[Tony bachler]

MY experiance "" I have 3 425s . (i think the best tractor in its catogory) Hours range From 169 to 4000 . The high hour one started over heating, at about 700 hours/4 years ago The thermastat was stuck closed. I went to the dealer he laied a new one on the counter and said. $38.50 Plus; I said not in my world. I left it out. Over 2500 hours later The tractor runs just as good as the other ones. And no overheating problems.. .I know there will be posters Reacting about the correct Opperating temp.. That is ok. As I made oil coolers For The Harley Davidson For Many years. and am quite Familyour with oil.. .And temps.. Take it out and try it. Some will say the water goes to fast it will not cool. Well some may like there bear warm.. That is ok.. Life is good.

 

[BobP]

Sounds like its over heating for sure . Radiator fins clear of clippings etc . Running with out a thermostat is not a good idea .Most of the time they will over heat with them out . The thermostat gives the rad time to cool the fluid before recycling it back through the motor as needed for the temperature setting of the thermostat . Really depends where you live and use of the machine ( hrs. run )for no thermostat . Fluid disappearing ...might be boiling over and out the reservoir . Oil still black or clean ? Smoking white with a anti freeze smell . don't just add water...... 50/50 is the norm and it raise the boiling point of the fluid . Adding just water diluting the mix may also cause it to over heat .It's not just anti freeze it should be csalled anti over heating down in the hot climate areas . I would drain the fluid .... clean the rad fins ....and change the thermostat. If that doesn't do it then when it's cold remove rad cap and run up to temperature if the fluid is not circulating then the pump may be bad . I have even seen a new thermostat fail . If you put the thermostat in a metal container with a thermometer ( candy type ( don't let the house boss see you ) ) and raise it to temp. rating with a propane torch then you should see it open . Something soooooo simple is really complex .