This is why you change oil
 

Sent the rover up to my cousin's (he's a LR mechanic) to get a head gasket job done and while pulling the heads off he found mounds of sludge. He says it is by far the worst he has ever seen and he thinks that is the reason why it was overheating. Hopefully the engine can be saved...It almost appears as if the previous owner has never changed oil in the 80,000 miles he had it. It makes me want to call him up and cuss him out for it and make him pay for the damage done.

I've seen worse than that.
Clean it up good and you'll be back on the road.

Also check your PCV system, which could contribute to this easily; even if oil was changed.

Some people get their oil changed on a regular basis but they don't have a clue as to the quality of oil going into it.

My mechanic told me when he had the valve covers off that mine had a lot of sludge also, that he couldn't see the head bolts.

My first thoughts were that the previous owner never changed the oil and then my mechanic explained to me that many people go to wal-mart to have their oil changed and they might just pay for house oil which can contribute to this even though the oil was changed regularly.

I have done a couple of flushes and use an additive also.

One word...Use good high quality diesel oil

That's actually 5 words.. But who's counting?

Me too. I remember a Honda Accord that came in for a major service. When we pulled the cover off to adjust the valves, you shouldn't see the rocker arms. They were completely covered in sludge.

Thing is this "sludge" isn't slimy. It's more like dirt and mud.

Yup get your shop vac and scraper/flat head screw driver out. After the first oil change you'll probably need to drop the pan and clean the oil pick up.