What is proper Operating Temperature

[BartToole]

Just retired to the country and have a JD 950 tractor (1979). Took me first time out to overheat the engine (idiot temperature light did not come on) and I have had to reolace the head. Because I am an engineer and need to look at guages, I had the mechanic install a temperature guage with the sensor at the back of the block near the seat and guages. Mechanic told me he had run the tractor on idle for an hour and it never got above 170. Said I should never let the temp get above 200 F. Under load the temp reaches 200 F within 10 minutes. Now I need to know what is the normal operting temperature and pressure of the system. I don't know how accurate this temperature system is. I have seen comments about checking the temperature at the radiator cap. What should the tmperature be? The tractor has a new water pump, thermostat, and radiator cap. I just flushed the radiator with Preston Flush.

 

[Rara Avis]

Just retired to the country and have a JD 950 tractor (1979). Took me first time out to overheat the engine (idiot temperature light did not come on) and I have had to reolace the head. Because I am an engineer and need to look at guages, I had the mechanic install a temperature guage with the sensor at the back of the block near the seat and guages. Mechanic told me he had run the tractor on idle for an hour and it never got above 170. Said I should never let the temp get above 200 F. Under load the temp reaches 200 F within 10 minutes. Now I need to know what is the normal operting temperature and pressure of the system. I don't know how accurate this temperature system is. I have seen comments about checking the temperature at the radiator cap. What should the tmperature be? The tractor has a new water pump, thermostat, and radiator cap. I just flushed the radiator with Preston Flush.

The idiot light should be come on at approximately 230 degrees.

Make sure you keep your debris screen clean...

Make sure your fan belt it properly tight and that the fan is pulling adequate air thru the radiator...

 

[BartToole]

Thanks. I know the 50/50 e.g./water boils at 225 at normal pressure. This pressure is elevated so that makes sense.

 

[kuboman]

200 seems a bit high. What temp of thermostat does it have? Did you flush the block out too? It make be cruded up.

 

[BartToole]

200 seems a bit high. What temp of thermostat does it have? Did you flush the block out too? It make be cruded up.

Thanks for the note I used the Preston flush, added to the radiator and filled with water. Then ran tractor for 3 hours as instructions suggest for severe clogging. Found out yesrteay that wifre from temp sender had broken off. Don't know how to flush the block. Everything points to 230 being the danger temp. Have not had boil over from radiator into overflow jar yet like I did when I first ran the tractor.

 

[jenkinsph]

When you flushed the system did you get a lot of crap out when you drained it? If so you may want to flush it again. When it cleans up enough I would refill with the proper anti freeze mix. That should clean up the block enough in most cases.

Might be a good idea to buy an infrared thermometer. You can scan across a radiator, hoses, engine block and get instant temperature readings. Also good to spot failing bearings and the like.

Tractors often operate in dusty environments that can plug radiators up, make sure the entire radiator is kept clean for proper air circulation across the whole radiator.

When you say the tractor overheated under load, just what were you doing?

 

[chriswheeler]

I installed a temp gage on my 950, and here in Nevada, temps ran around 185 under load brush hogging. Cleaning the cooling system internally helps, but the biggest thing I remember is that keeping the cuttings clear of the radiator cooling fins made a bigger difference. When temps went up, always needed to clean the screen in front of the radiator and sometimes blow out the fins with compressed air. I got into a routine that when I finished brush hogging, I always cleaned out the front screen, no more problems. I'd also run a thinner mix of anti-freeze, 30% or so with protection down to -10 degrees. If that doesn't do it, I'd change the thermostat. Ended up selling the 950 a few years ago replacing it with something with power steering.
Chris
Chris

 

[BartToole]

When you flushed the system did you get a lot of crap out when you drained it? If so you may want to flush it again. When it cleans up enough I would refill with the proper anti freeze mix. That should clean up the block enough in most cases.

Might be a good idea to buy an infrared thermometer. You can scan across a radiator, hoses, engine block and get instant temperature readings. Also good to spot failing bearings and the like.

Tractors often operate in dusty environments that can plug radiators up, make sure the entire radiator is kept clean for proper air circulation across the whole radiator.

When you say the tractor overheated under load, just what were you doing?

I did not see any crude come out with the flush. Followed with two water flushes and they looked clean also. Have read about the infrared thermometer and will probably get one. Have thought there may be plugs in the rdiator that a boil out might cure. Problem with infrared, it will show me hot and cold spots, but not the temp at which I should be alarmed. If red light comes on at 230 when water returns to radiator (using a John Deere probe), how do I calibrate to an infrared thermometer which is looking at the surface of thermostat.

 

[BartToole]

I read where someone lse had installed a temp gauge and ran at 170 buhs hogging. As an engineer, I need to be sure the temp I am mesuring agrees with the temp John Deere cautions about (the red light). The mechanic wasn't pleased with the point he put it in but said it was the only place he could find. I think a severe wrning would be if I get steam coming from the overflow tank.

I have been very careful about the front screen. I really haven't been able to run long enough to clog it up.

Thanks for everyones help.

 

[amaxwell]

I read where someone lse had installed a temp gauge and ran at 170 buhs hogging. As an engineer, I need to be sure the temp I am mesuring agrees with the temp John Deere cautions about (the red light). The mechanic wasn't pleased with the point he put it in but said it was the only place he could find. I think a severe wrning would be if I get steam coming from the overflow tank.

I have been very careful about the front screen. I really haven't been able to run long enough to clog it up.

Thanks for everyones help.

As someone mentioned earlier check your radiator to make sure there is "airflow" . I had to remove the radiator and clear the small fins on my old ford. The fins openings were clogged with years of small seeds and dirt. I made a cleaning tool of plastic that would fit thru the fins . It was a long process inserting the tool in each little opening , but solved my over heating issue.