something wrong with cooling system

[ugabulldog]

Not sure if I have bad sensor, gauge or thermostat, something else, or neither....temp gauge moves but only to line between blue (cold) and green, not into green. I ran for 30 min today, block was warm, upper hose was slightly warm and lower hose was cold. I removed rad cap and nothing spewed out and coolant wasn't circulating with engine on?

 

[Dave M7040]

Not sure if I have bad sensor, gauge or thermostat, something else, or neither....temp gauge moves but only to line between blue (cold) and green, not into green. I ran for 30 min today, block was warm, upper hose was slightly warm and lower hose was cold. I removed rad cap and nothing spewed out and coolant wasn't circulating with engine on?

Buy a infra red temp gun and then get some real numbers. $15 at amazon.com
Amazon.com: Etekcity Lasergrip 774 Non-contact Digital Laser Infrared Thermometer Temperature Gun -58℉~ 716℉ (-5℃ ~ 38℃), Yellow and Black: Kitchen & Dining

If you have warm water in the rad and the engine is not up to normal temp, then thermostat is opening too soon.

To do any reasonable trouble shooting you need some basic tools

Dave M7040

 

[ugabulldog]

how long should engine have to run to build up pressure in radiator? maybe it is just not running long enough?

 

[Jerry/MT]

Not sure if I have bad sensor, gauge or thermostat, something else, or neither....temp gauge moves but only to line between blue (cold) and green, not into green. I ran for 30 min today, block was warm, upper hose was slightly warm and lower hose was cold. I removed rad cap and nothing spewed out and coolant wasn't circulating with engine on?

Unlike spark ignition engines, compression ignition engines( diesels) run with widely variable peak gas temperatures. Therefore it's hard to warm a diesel up at idle or low power. The peak gas temperature is low at low power output. So if you are not working the snot out of the engine it will run cool. That's normal for a diesel. If you are working it hard and the coolant temperature is low, I'd suspect a defective thermostat-one that is opening too soon or is stuck open.

 

[ugabulldog]

Unlike spark ignition engines, compression ignition engines( diesels) run with widely variable peak gas temperatures. Therefore it's hard to warm a diesel up at idle or low power. The peak gas temperature is low at low power output. So if you are not working the snot out of the engine it will run cool. That's normal for a diesel. If you are working it hard and the coolant temperature is low, I'd suspect a defective thermostat-one that is opening too soon or is stuck open.

Thanks Jerry, so how long should it take at say 1800 rpms to build up pressure in radiator where it spews when opening cap?

 

[Billrog]

I often plow snow at 3500 rpm for and hr. or more and the temp. gauge never gets up to the center but during summer it would be in the normal operating range in 15 to 20 mins. at 1800 rpm.

 

[jaxs]

Pressure when removing cap isn't a reliable test.

 

[ugabulldog]

is there a way to to make sure thermostat is working and not open or closed without removing it?

 

[Jerry/MT]

Thanks Jerry, so how long should it take at say 1800 rpms to build up pressure in radiator where it spews when opening cap?

Depends on the load at 1800 rpms. If it's not under load at 1800 rpms the peak gas temperatures will still be low. If the tractor is in neutral and you advance thee throttle, it doesn't take much fuel to get to max rpm and hold it there. As you add load the fuel flow increases and the peak temperature increases.

 

[Jerry/MT]

is there a way to to make sure thermostat is working and not open or closed without removing it?

Not without measuring the coolant temperature at the thermostat. The thermostat should start to open at the temperature it is spec'ed at. If you have an infra thermometer (~$20 at HF) you can point it at the coolant outlet elbow ahead of the thermostat and measure the temperature. It will be close to the coolant temperature coming out of the head. If that temperature measurement is less than the thermostat opening temperature than the thermostat should be closed. Now open the rad cap (CAREFULLY!)and see if coolant is entering the radiator because it should not be. If it is entering the radiator than thermostat is bad. If the temperature is above the spec'ed opening temperature and there is no coolant entering the radiator than the thermostat is bad.