So once again, my 97 Disco is having overheating issue's and I can't figure out wtf is wrong with it. I've owned the truck for 10 years and never had an issue with it overheating until a mechanic did a coolant change a while back. If anyone is near Brooklyn, NY and can help with this or point me in the right direction, that would be great.

FYI, I've already taken it to a reputable radiator shop who said nothing is wrong with the radiator. I've got a new coolant box, therm, therm sensor in it and still, it overheats once I begin to drive it

btw, the Disco has 156K on the motor and I've had it since there was 45K

 

How's the water pump?

 

Could be your fan clutch. I'm sure there are threads on here about how to test it. I think it is supposed to be fairly free wheeling when spun by hand and the engine is cold, but when warmed up it should have some resistance to spinning.

 

Was the thermostat changed when the coolant was? If so, what temp thermostat was installed? If he called the local parts store and said "Send me a thermostat for a '97 discovery." the odds are very high that it's too high a temp, likely a 195. It should be a 180.

 

When the radiator shop checked everything, they said the WP was fine but I'll check again. maybe it's time to just replace it and see if that helps.

 

The thermostats was changed with a LR one as I dropped off the part for him.

 

Ok, then it should be an 88c which is correct.
Then yeah, check the viscous clutch, if that's good, then look at the waterpump.
I'm assuming the radiator shop made sure the fins on it and the A/C condenser were clear.

I was suspect of the thermostat because you said overheating started right after the coolant change/

 

Tom, how do I check the viscous clutch to see if it's good? Also, the shop didn't check the fins because they couldn't get it to overheat so they couldn't find a problem with it

 

If anybody took your fan belt off make sure it was reinstalled correctly (look at a diagram). The chevy fan clutch mod is a very easy/cheap DIY project. See the stickies section for instructions. Congrats on keeping it going for ten years and 100k+ miles lol.

 

That is incorrect, having just gone through the thermostat replacement on my '96. The 195 is the correct Temp thermostat for the motor. Actually, the correct temp is 88 degrees celsius, to be accurate, which converts to 190.4 degrees F. The 180 is for Discovery II's, as they have a smaller radiator. Putting a 180 in to keep it cool (regardless of all the posts floating around here stating the contrary) would just be compensating for some other issue which needs to be rectified. Barring one or more blocked coolant passages somewhere in the motor you are running out of stuff that could be wrong.

Just to be devil's advocate here, how do you know it is overheating? Are you just going off the gauge (which could be lying to you) or is it obviously exhibiting othe signs?