As temps warm up here in Arizona, I became concerned about the engine temp on my 2003 Disco 2. Normal cruising I would see 188-195 on the Scangauge. Last week on a long trip I noticed the temp getting up to 208-215 while doing 75 on the freeway. I ordered the warm weather (weak spring) thermostat from AB and installed it bleeding the air out of the system. Now, driving around town I'm seeing temps of 200-209!?!? I double checked to see if there was any air in the system but it looked good. Any suggestions???

 

It is normal to run hotter in hot weather on these trucks... What is the opening temp and brand of the thermostat you bought? If it is a stock 88 degree C then your temps are also normal. Most folks on here use the 82C (180F) thermostat.

There have also been many reports on here recently about defective and mislabeled stats being sold and delivered.

The way to double check for any air in the system is to open the bleed screw when the engine is stone cold. If you can add any coolant into the bleed hole, you found some air and displaced it.

 

This was supposed to be a 180° thermostat (weak spring) that was supposed to keep the temp closer to 180°. It was ordered from Altantic British and had the white plastic housing but no temp marked on the outside. I'll re-check for air using the method you described. Thanks!

 

The 180 Genuine are Gray, the White Genuine are 197.

 

Probably a Motorad.

 

Read the inside stamp on the thermostat. 180F will read 82C. If it’s a motorad from AB get your $$ back as those are 33.00 all day long from Auto Zone!

 

Imprecise. That is the temperature the thermostat changes flow from bypass to cooling.
Running temperature is affected by ambient, speed, exertion, towing, rpm, coolant mass, air flow, heat exchange, hills... The most perfect 180°F imaginable thermostat does not have to maintain such coolant temperature. Its job is only to fully open flow to radiator and to fully close bypass at such, the rest is not its business.

 

I’ve had the warm weather thermostat from Atlantic British on 2 of my discos for 8 years. It’s always worked fine.

 

Just to add my Disco runs around 183 -185 at around 70 to 75 deg with pops up to 188 - 190 while idling. I have the 180

It hit 35 C or around 95 here yesterday the Disco ran 188 to 194 below 60 mph, 194 to 199 at 75 mph. Hit as high a 206 right after the freeway, then dropped back down to 188. Traveled home at less than 55 never cracked 188 other than up a long steep hill.

That seems pretty normal to me

 

For the many who will read this in the future, could you specify which 180 rather than "the 180."