I recently picked up a well maintained 2004 D2, but with 139K miles. I know the head gaskets were replaced. What proactive measures can I take to protect the engine? Change the thermostat, hoses, etc?

 

Best thing I’ve ever done to my disco is swap to green peak antifreeze and do the inline thermostat mod with a 180 degreee thermostat. Temps have a lot to do with head gasket problems and the mod will keep temps in the 180-190 range. I also swapped my viscous fan to a 99-02 fan with a Hayden sever duty fan clutch.

 

Check out the big service in my signature. Pretty much everything you need there.

 

I run "Cool Down" in the radiator which dropped temps about 6 degrees F for me. Avoiding overheating is important.

I use Turbo Maxx in my engine oil, front+rear differential oil, and transfer case (I do NOT use it in my transmission). What I noticed straight off after adding this to the engine oil was that my valve train noise completely quieted down.

I did an 1100 mile road trip this weekend with gas mileage varying from 15.1 mpg with A/C on during the day to 16.8 mpg with A/C off at night (75 mph cruise).



Buy the $4 ELM327 and download the smartphone app so that you can see your engine codes and temperature in real-time. Cheap.


Grease your front driveshaft zerks. This is basically free life-extensions for it.

 

Alex- the 180 thermostat is just the basic OEM replacement thermostat?

Thermostat Discovery Series II (Part # PEM100990)

What is the low thermostat?

Finally, what is a good cheap OBD2 reader?

Thanks!

 

This is the proper 180 stat if you just replace the original rather than doing the inline mod.

https://www.lucky8llc.com/products/low-temp-thermostat

Low thermostat just means low temp.

The one you linked is junk. Don't waste your money.

 

Autel 619 is a good reader and is affordable..

 

I've done the 180* thermostat, but I don't really see the point in the inline mod.

Running cooler is great and all, but when you start talking about high mileage vehicles you have to start planning for failures. It's not about running your truck 15* cooler, it's about prolonging the life of the components. Or better yet, replacing the old components with new components before they fail (plugs, wires, coils, hoses, belt, etc.) Also ensuring proper maintenance and fluid levels such as oil changes, transmission fluid, coolant levels, driveshaft greased, etc.

Or you swap in a brand new engine and make your high mileage D2 a low mileage D2!