Why would cause 2 heater plugs to be dry and covered in oil

 

And these are kinda where in which Rover? Electrical plugs or metal lines or rubber? Any pix?

If you are talking about metal lines that run to the evaporator (the thing that makes cold air with the AC refrigerant flowing in it) that would be a "freon" or refrigerant leak, as that closed system also has a special oil inside that lubricates the compressor. Sometimes that is an O-ring in a fitting. If you are not familiar with AC systems, this is not the time to learn. Cheaper to take to shop for modest repair. They will recover what freon is left (if any), fix the leak, vac system down, refil with specified quantity of freon. Tools to do all this (including recovery) cost more than my used D1.

 

This is for the landrover discovery

 

Year? Approximate location of what you see, and what is near there?

 

Dude we have no idea what "heater plugs" are.
We need to know the year, the engine you have and where you live before we can help you in any way.

 

Sorry not a mackanic I'm on about me glow plugs two were dry and two were covered in oil all the way up the shaft and its a disco M reg

 

Glow plug heater plug - As you can see, it screws into the engine and does not have a rubber gasket, etc. But the shaft is not very long on the part that you could see. Like many things Rover, oil (or diesel fuel) can collect anywhere. I'd would be cleaning them off with something like spray brake parts cleaner, checking tightness (20 newton meter), and seeing how long before more oil shows up. If replacing, I'd do the whole set. Make sure you get ones exactly for your engine, the length can vary.

 

"M" reg means nothing to us here in the United States.
Knowing it was a diesel engine would have been so much more helpful in your original post.
We dont have diesel Land Rovers here.