Yeah Yeah more about head gaskets
 

So this is my third Disco i've owned, one claimed in a divorce and one sold to the neighbor kid... I currently have an '03 with 75,000 miles on it. I just started getting the check engine light on and it came up as a bank 2 sensor error.

Well it appears that the O2 sensor is covered in oil and shorting out. I took it into the stealership and they told me I was leaking oil "everywhere" and I needed a new head gasket/throttle body/ yadda yadda... they also said its a 10 hour project and would cost $4500...

Now, i've been working on jeeps and chevy products since I could reach the pedals. The emissions crap on this thing scares the crap out of me, but other than torque specs and and tightening sequences, am I going to find anything in here that's gonna make a relatively knowledgable gear head melt down?

The dealership said that the gaskets "just fail" I've gotta believe that something is causing this? Other than checking to see if the heads are warped, is there anything else I should be looking for?

Also, when I have it stripped down, what else should I do preventively? I'm a big fan of if it ain't broke don't fix it... but, I've gotten the feeling if I get it down this far, there might be some things to tidy up while I'm there.

Any help that would prevent doing things twice would be greatly appreciated.

I did my head gaskets and I had never worked on an engine before. Just download the Rave CD and follow the directions and you will be fine. The engine itself is actually an old buick V8. The machinist I took mine to did not believe me that is was a Land Rover head.

http://sancarlosradiator.com/dex-cool.htm

Gaskets dont just fail at 75k unless they are defective.
99% of all DII's have head gasket leaks in less then 100k, all DII's came from the factory with DexCool, you sound like a half way intelligent guy, you do the math.

Use Peak Global or Prestone coolant, make sure it is aluminum safe and you are good to go. (I used to sell bulk coolant)

If you can do the heads on a 350 you can do the heads on this, just make sure you get the correct gasket kit and new head bolts.
www.atlanticbritish.com

Sooner you learn to not go to the dealer, the sooner you will start saving money.
First, exactly what fault codes did you get, if you don't know, get them read at a local parts store and get back to us with the exact 4 digit fault code number so we can help you.

Yeah Yeah more about head gaskets
 

The fault codes I was getting was P0174 and P0150... system too lean and bank 2 circuit... they don't show up in the Rave or the manual, I looked them up online. The system too lean was fixed when I did the tune up

So how many miles on your engine?
With a 150 02 code, you will get that lean code, so depending on your mileage you may want to change all 4 02's or may just the one.

75,000... the front two are pretty saturated with oil, so i'm gonna change them first. But if it's prudent to change the rears, mights as well do that too, i guess.