How hard of a job is replacing the thermostat? I just got a Scanguage for my newly aquired DII and am getting temps up to 215, I would like to bring this down. I'm looking at the 180* thermostat as so many seem to have luck with this unit.

The Atlantic British video makes it seem like this is a very easy replacement job. I'm not convinced after reading the other recent thread. What tools should I ensure I have on hand before tackling this one?

 

It is not a hard job at all but if the current one has never been touched you likely will have a semi-tough time removing it from the hoses. You really just need a pair of pliers (or screwdriver depending on the type of hose clamps you have) and it is relatively accessible. You will need to drain your coolant first though (unless you like making and cleaning up messes).

 

I always through the inline thermostat mod out there as an option. I ordered parts for mine last night.

 

Hmm, tell me more.

 

*throw

Can't believe I misspelled that.

Anyway, the inline thermostat mod does away with the factory bypass style cooling system and converts you to a direct inline cooling system with no bypass, more like you would find on a small block Chevy, which is actually what you get the thermostat from. You have to order an inline thermostat housing. This one is the only one I can find on the market Meziere WN0073 Inline Thermostat Housing 1 1 2'' Slip on Hose Inlet | eBay

Then you need a different lower hose from some BMW I believe to delete the factory thermostat. I ordered this one Radiator Coolant Hose Curved Radiator Hose Upper Lower Dayco 70112 | eBay. It may or may not be the right one, but I think it is. The picture is a generic hose image and not the shape you need.

Then you need a Chevy style thermostat. There's a little debate as to which temp stat to use between 175 and 180. I went with 180, but I expect to have to go down to a 170-175 because I'm running dual transmission coolers in front of my radiator since I tow a lot (wrote up coming soon!)

Its important to note, the thermostat does NOT go in the facory location. It will go in the upper hose coming from the intake manifold. If you search Inline Stat mod, you should be able to find it. I may also have a link to the original post under the link in my signature.

 

Upon cross referencing numbers, that's the wrong hose. You need a Gates 23405. Original post says its cheapest on rock auto.

 

Looks cool, what is the advantage?

I have the 180* thermostat coming so I think I'm going to stick with this one for now. Maybe something to do in the future.

 

It just gives you more stable temperatures. The stock system allows for a lot of variation.

 

If your truck still has the original spring-type hose clamps it'll be easier to release and reinstall them if you have Channel Lock pliers (called water pump pliers where I grew up).

The thermostat can be changed entirely from the top side. Contrary to what Titus said you do not need to drain the radiator.

I changed the one in my truck again three months ago. It probably took me about 20-30 minutes. First remove the upper fan shroud. Put a bucket or drain pan below the thermostat and you can capture and reuse the coolant if you like. I filtered mine twice through a double layer of paper towels in a funnel. I collected and reused about a gallon.

If your temps are still above 200 degrees after changing the thermostat the problem is most likely your radiator, which may be partially clogged (although it could be the fan clutch). Unlike some radiators in some other (older) vehicles it's impractical to service or rebuild a DII radiator. Replacement radiators are ~$200 (I recall) and can be replaced by a DIYer although it's kind of a PITA job.

When do you hit 215 degrees? If that's at idle what are your temps cruising on the highway? Acceptable (i.e. 190s) temps on the highway with 215 at stoplights indicates a fan clutch problem. Consistently high (200+) temps indicate a partially clogged radiator.

 

My temps are 205-211 while moving, spike to 215 at idle.