Ok so my Disco constantly runs cold I have a 180 High flow in the inline thermostat mod. My average operating temperature is 167 degs at 68 f ambient and lower on flats.

Running uphill at about 7% grade and 24 mph the Disco got up to 185/185. I heard the fan clutch engage briefly and temps stabilized at 185. Note I was in high range and 2nd gear
The fan clutch engages at start up.

Checking the return hose from the lower intake with an ir thermometer, the temp is the almost exactly the same as the reading at the OBD port

I would like to eliminate a mis-reading temp sensor, so my question is it a coolant dump to change it out?

I know Disco owner OCD right

 

I think you are asking how tough it is to change. I did mine recently. If you have a 22mm socket that is just just tall enough to clear the harness it is super easy. Post is below. A bit of fluid came out, but not enough to worry about.

https://landroverforums.com/forum/di...g-temp-122479/

 

Maybe siphon out enough into a bucket to get below the level.

 

If the engine is cold almost no coolant will be lost when you quickly swap out the sensor.

But I am kinda lost. You wrote the IR thermometer matched the OBD. That sounds OK to me. Why change it?

 

@WaltNYC I am not there yet, I need swap a different thermostat in, but I like to be prepared. It is just weird that the disco rarely gets hot, heater is fine at least for me.

I am very OCD about my truck I spend a lot time far from highways, with no cell service and iffy sat service, deep valleys in the woods, so I like my truck to run well. This is just an itch I gotta scratch

 

It's interesting that you are having issues with a Disco running COOL!
My Disco was running hot with the stock thermostat in it and I elected to put the Jaguar thermostat housing in it with a 180 degree thermostat.
Now I am finding the same thing as you. On the road it runs about 154 degrees and only gets up to about 190 or so if I leave it idling on a really hot day.
Nice problem to have I guess but was quite unexpected!

 

Richard, maybe I'm being thick, but I don't understand. If you believe the IR reading to be accurate, and it matches the OBD, which is fed by the temp sensor, it would seem to me that all is well.

Now, I have had all sorts of trouble finding a correctly calibrated temp sensor. Even an OEM temp sensor yields a reading 5-10 degrees lower than the IR gun.