Here's the background. I have a 2003 SE with about 60k miles on it. I bought it in January of this year, and after driving it for about 500 trouble free miles, I did an engine flush, Seafoam treatment, and changed the oil. Soon after that, I started getting a pretty good engine knock at idle once the engine would get hot. I added an oil pressure gauge to rule out oil pressure issues since it is a 2003 (the VIN does NOT fall in the troubled range). The gauge showed good pressure at all times - never below 15 psi.

After driving with the knock for about 1500 miles, I took the Disco on my first extended trip and drove it about 350 miles one way. When I arrived at the destination, the knock was gone! I drove around for about 2 more weeks and probably about 1000 miles with no knock. I thought something miraculous had happend. However, yesterday the knock resurfaced. Same as before, only there when the engine is hot and it goes away when engine speed increases above idle.

My thought after all this is lifter noise. The knock seems to come from the top, driver's side of the engine. It is goes up and down with rpm, but either goes away or cannot be heard above 1200 rpm or so. Other than the knock, the engine runs smoothly and performs great. Is it possible for a lifter to stop pressurizing and cause a knock. And then over an extended period of operation (i.e. the 350 mile trip), the lifter starting pressurizing again? But now after a few hundred miles of city driving (probably 10 miles per engine start), the lifter is failing again?

 

hahaha. I have had the same problem with my 96'. I can't figure it out for the life of me. the only thing that i could come up with is that there is gunk on the bottom of the oil pan (from the flush) and on occasion it sucks up some of that gunk and plugs the pick up tube.

if you want you could drop your pan and check the pick up tube.

wish i had more info for you

 

Not sure while you are driving while your engine is knocking, but if you don't want to buy a new engine, you might get it into a shop like yesterday.

 

cam shaft isn't that important is it? =)

 

The dealer's solution was to replace the engine. They said they'd check the top end, but digging deeper than that wasn't worth the diagnostic cost. With that in mind, I picked up a used engine out of an '04 that was wrecked. That's my insurance policy and also the reason why I'm still driving the vehicle and at the same time trying to figure out why the problem I described was temporarily fixed with an extended trip.

 

Could be a lifter that lost pressure, and if so it will run that way forever.
Could be junk stuck somewhere.
Could be the voices in your head.
Change the oil again and see what happens, like you said you have another engine.

 

Spike, have you ever heard of a lifter with problems that worked ok for a while after an extended period of driving and then goes back to making noise a few weeks later?

 

on most "engine flush" type treatments they even recommend cleaning or changing the pick up tube from the oil pan to the oil pump. if you do a flush and all that crap that you flushed out doesn't come out the drain hole, it can cause a knock/tap. either change the oil again or clean out the pick up tube (which means and oil change anyway). This is not specific to Land Rovers.

 

I changed the oil three times after the flush trying various oil weights to no avail. I suppose the long drive could have dislodged more junk, but I really don't think that's it. If the pickup tube was blocked enough to cause knocking, wouldn't I see low oil pressure?

 

hmm well i sure didn't know you changed the oil three times. you would think that would have gotten it all out. I'm out of options here. i would say lifter is bad but you say it comes and goes right? sticky lifter would cause knocking all day everyday.