I'm having an unusual problem with My 02 Disco that I cant seem to find any answers to. We are getting into the winter here in Ohio, with the average daily temp being between 30 and 50 degrees, and I've noticed my truck running extremely cool according to the temp gage which barely rises above the blue zone. Curious about the accuracy of the gage, I checked the engine temp at the radiator and at the block with a laser thermometer and recorded temps in the 80s and 90s. Not much heat coming out of vents either. Just serviced the cooling system about 20k ago, including a new thermostat from AB. Also the radiator was replaced about 15k ago. Any Ideas???

 

that factory guage will only move after you have melted down your motor.
how long ago was 20000 miles, 1 year, 3-years ?

 

If you're not low on coolant, and if you don't have an enormous air bubble in your cooling system, my money is on a thermostat that's stuck open.

Even with a stuck thermostat, 90º is damn cold after driving for some time.

 

You mean 180* to 190*, right? or are you measuring in Celsius? I doubt you would be able to keep the temps down to 90*F even if you tried...

 

What temp should a disco run at on avg?

 

Depends on the condition of the cooling system and what t-stat you are running, but usually between 190 - 212. When I was running a factory stat I would usually run 195ish on the highway, and about 200-204 around town, with my warm idle spiking to 212 every once in a while. Now that I am running the motorad 180 t-stat I am about 188-190 on the freeway, 194 around town, and my warm idle spiking to 200 once in a while.

 

Yes, 170 to 190 really, and the 'stat is a little more than a year old. Could it be sticking already?

 

It could be. You can always pull it out and test it by putting it in a pot of water, use a thermometer to measure water temp, and heat the water and see when the stat opens and then turn off the heat to see if it closes properly.

 

for $ 40 you can get a new 180 degree stat on amazon, why mess around

 

My bet is low on coolant or air in the system. Heater not working is a dead give away.