I live in Phoenix, AZ where the temp is regularly above 100 degrees for a large portion of the year, so I decided that it would be a good idea to upgrade to the 180 degree thermostat that everyone seems to swear by.

I acquired the Motorad 439-180, a new lower radiator house, 2 gallons of Peak 50/50 coolant/water mix (last guy ran green, figured I'd stay with green stuff).

The work was easy, about an hour in my driveway swapping out the hose and thermostat, flushed the system with distilled water (gravity flush with funnel) and put in the new coolant. Bled the system pretty thoroughly, everything seemed good to go.

Got on the road for a test, mile into it I'm now averaging over 200 degrees when I rarely went over 195 with my old thermostat. Brought it home, parked it and waiting for it to cool down now so I can check the levels and bleed it again.

Could I have a faulty thermostat or is there air in my system? Any advice would be greatly appreciated. Thanks.

 

Probably air in the system. Drive it then let it cool, bleed again. Check the level everyday and fill as necessary. If you notice the level dropping after it cools off, it has air.

 

Thanks for the advice. I'll run a few more cycles to bleed and top off accordingly.

 

Double check that your condenser fan is coming on at 210 degree, also those motorad T-stast are notoriously known for being bad and not opening for well over 190 degrees. The key is to use a OEM TD5 thermostat (dark Gray).
But check the fan.

 

Ditto that ^^^

This is a lesson in LR ownership, go cheap at your own peril when maintaining these vehicles.

You may get the vehicle for cheap but that doesn't mean you get to maintain it that way.

 

The fan is consistently coming on at 210 degrees so that is not an issue. I brought it on another run around the block today and it's still wanting to settle at around 205. I'm letting it cool down now to give it one more try at bleeding the system just to make sure there isn't excessive air in the system. I'm starting to agree that this t-stat probably wasn't the best choice.

 

+1 on the OEM dark gray thermostat, I installed mine yesterday and it brought my truck down from 205+ to 182-184

 

Can you send me a link? I want to buy one of these now

 

GENUINE LOW TEMP THERMOSTAT ? Lucky 8 Parts and Accesories for Land Rovers

May also want to get a front driveshaft if you haven't already?

 

Yep OEM Grey Thermostat is the one to get if you're sticking with the OEM setup. When I've replaced D2 thermostats I've found a Scangauge II helps a lot. After installing the new thermostat, and adding coolant, let it idle to 195F, shut it off, and let it sit overnight. Then the next morning top off the coolant jug, then once again let it idle until 195F, and let it sit overnight again. Then check your coolant level and top off if necessary and go for a drive. At that point 99.9% of the air in the system should be gone. I've used that technique on several D2's now and it sure beats parking it at a 90 degree angle, and up on ramps only to still have an air pocket....