Tractor not warming up

PoorMansCat · Jan 22, 2011

I would check and verify that the gauge is correct before disassembling anything. If you have an temperature gun point it at the top radiator hose near the engine and compare it to the gauge reading.
Another thing to consider, IS it full of coolant. An engine that has air trapped in the system or is low on coolant will sometimes show low coolant temp. (this is due to the bulb on the sensor not being submerged in coolant.) The gauge will read hot air, but not accurately.
As others have stated, being a used tractor, you never know what somebody else may have done, but it is never a good idea to leave the regulator out of the cooling system.
Engines need a regulator in the cooling system to keep the engine components up to a desirable temperature to help aid piston ring seal, keep the engine oil temp high enough to burn off condensation, etc..
In extreme cases, the absense of a regulator can actually cause piston seizure.

Jerry/MT · Jan 22, 2011

One Acre Farm said:
Did some semi heavy work today w my new to me tractor and noticed again that it won't get out of the yellow in the engine temp gauge, had the tractor running at least an hour at around 1500rpm(540 pto is right around 2100rpm) I know the gauge works, cause when I start her up, she's well below. Any ideas?

Unlike gas engines which, at a given ambient temperature, run at relatively constant peak gas temperatures versus rpm (that's determined by fuel/air ratio and compression ratio and throttle position), diesels run at variable peak gas temperatures versus rpm (big variations in fuel air ratio and no throttling of the intake airflow). In general, the slower the diesel engine runs, the lower the peak gas temperature in the cylinder. That's why you'll have a hard time warming it up by just idling it. You need to increase the rpms and the work output by putting it under load.Running your engine at 1500 rpm when it is rated at probably near 2500 for max power, tells me you are running it at the low end of the peak gas temperatures. That's the physics of the engine side of this discussion.

Before you do anything, work your machine a little harder (1800-1900 rpm) and see if the temperature indication increases. If it doesn't, check the thermostat.
Remove it from the housing just below where the upper hose comes out of the cylinder head. Heat some water to whatever temperature your thermostat is rated at (it's usually marked on the thermostat), and put the thermostat into that water and see if it opens. If it does, thermostat is good. If it doesn't, replace the thermostat.) if you want to forego this experiment, just buy a new thermostat and replace it.

Re install a good thermostat in your engine and work the engine to bring it up to temperature. Let the engine cool, for an hour and then CAREFULLY REMOVE THE RADIATOR CAP and restart the engine. Look into the top of the radiator and see if water is entering the top of the radiator from the top hose. If it is, measure the temperature and note the position on the temperature gauge on the tractor. (If it isn't entering the radiator, run the engine with the cap off till it does then measure the temperature.) You'll now have a calibration point between the thermometer and the gauge. Compare that temperature to the temperature you noted on the thermostat.

If you are at the correct measured temperature relative to the thermostats rating, and the gauge reads low, then it's possible your temperature sensor's output is incorrect but I doubt there is any data to tell you where on the temperature gauge you should be except "in the green band".
My guess is that you are running the engine at too low a power and it's ot warming up at the ambient temperature you're working it at. That's why you're seeing what you're seeing. However, it is also possible though not as probable you could also have a bad thermostat or a bad sensor.

Egon · Jan 23, 2011

there is a big hose running from the top of your radiator to the front of your engine. This hose connects to a metal fitting that is then bolted to the engine. Remove those two or three bolts, that hose and fitting will pull off, exposing your thermostat.

Drain the coolant before doing the above work.:thumbsup:

Have you placed your hand on the top of the rad to check for heat. If it's comfortable it's too cold.

kevinj · Jan 23, 2011

Don87 said:
There are no shutters on the 2002 freightliner I'm running now, nor were there shutters on the 2009 Prostar I was running a year and a half ago, or the other 'half dozen' Internationals, nor the Volvos I drove over the past ten years.

You probably have a clutch fan and other methods of control on the newer trucks

herringchoker · Jan 23, 2011

I think radiator shutters disappeared when the air-to-air intercoolers arrived on the scene, at least that was the case with the Freightliners and one Kenworth that I owned. Don't want to block airflow to the intercooler.

clemsonfor · Jan 23, 2011

Jerry/MT said:
Unlike gas engines which, at a given ambient temperature, run at relatively constant peak gas temperatures versus rpm (that's determined by fuel/air ratio and compression ratio and throttle position), diesels run at variable peak gas temperatures versus rpm (big variations in fuel air ratio and no throttling of the intake airflow). In general, the slower the diesel engine runs, the lower the peak gas temperature in the cylinder. That's why you'll have a hard time warming it up by just idling it. You need to increase the rpms and the work output by putting it under load.Running your engine at 1500 rpm when it is rated at probably near 2500 for max power, tells me you are running it at the low end of the peak gas temperatures. That's the physics of the engine side of this discussion.

Before you do anything, work your machine a little harder (1800-1900 rpm) and see if the temperature indication increases. If it doesn't, check the thermostat.
Remove it from the housing just below where the upper hose comes out of the cylinder head. Heat some water to whatever temperature your thermostat is rated at (it's usually marked on the thermostat), and put the thermostat into that water and see if it opens. If it does, thermostat is good. If it doesn't, replace the thermostat.) if you want to forego this experiment, just buy a new thermostat and replace it.

Re install a good thermostat in your engine and work the engine to bring it up to temperature. Let the engine cool, for an hour and then CAREFULLY REMOVE THE RADIATOR CAP and restart the engine. Look into the top of the radiator and see if water is entering the top of the radiator from the top hose. If it is, measure the temperature and note the position on the temperature gauge on the tractor. (If it isn't entering the radiator, run the engine with the cap off till it does then measure the temperature.) You'll now have a calibration point between the thermometer and the gauge. Compare that temperature to the temperature you noted on the thermostat.

If you are at the correct measured temperature relative to the thermostats rating, and the gauge reads low, then it's possible your temperature sensor's output is incorrect but I doubt there is any data to tell you where on the temperature gauge you should be except "in the green band".
My guess is that you are running the engine at too low a power and it's ot warming up at the ambient temperature you're working it at. That's why you're seeing what you're seeing. However, it is also psossible though not a sprobable you could also have a bad thermostat or a bad sensor.

Hey i agree with everything you said about not lugging a deisel and it needs to operate at say 90% throttle to be efficient and have all its power.

But i think the OP said that he was running at the PTO speed which equated to 1500 RPMS. I know nothing about his tractor but that seems way to low to me, but again i am just pointing to what he said.

Saying this if he turns 1900rpms he will be overspinning his bushhog.

kevinj · Jan 23, 2011

clemsonfor said:
Hey i agree with everything you said about not lugging a deisel and it needs to operate at say 90% throttle to be efficient and have all its power.

But i think the OP said that he was running at the PTO speed which equated to 1500 RPMS. I know nothing about his tractor but that seems way to low to me, but again i am just pointing to what he said.

Saying this if he turns 1900rpms he will be overspinning his bushhog.

He said PTO speed was at 2100 rpm.

JoelD · Jan 23, 2011

Diamondpilot said:
Check the T-stat or better yet spend $5 and replace it. You may find it missing all together since you bought it used.

Chris

Precisely my first thought.

Joel

beeforty · Jan 24, 2011

I had opposite problem, my overheat light came on almost with start up. Checked everything like others have recomended, all ok, so changed the temp bulb.