I have an engine noise, sounds like a bearing knock. Not coming from valves or lifters, as it's down low,almost heard better from under the truck. But only happens at idle, totally disappears at any rpm above idle. I have not checked the oil pressure yet, but if it is running low at idle, would that make sense why it only happens at idle?

Or could it be something different altogether?

 

Exhaust gaskets?

 

Does it sound like alot of air leaking or like someone is taking a hammer and methodically tapping on your block?

 

Well, I ruled out exhaust leaks. I tried taping on the catylitic converters and couldn't hear anything loose or rattling inside.

Tomorow, I am going to pull plug wires one at a time to see if it stops at a specific cyl.

It's not an air sound, a definite knock. But as soon as I touch the throttle, it goes away.

If cought early enough, could I throw new rod bearings on through pulling the sump and maybe get lucky and fix it?

 

Depends on the cause of the knock. If you only have a bad bearing causing play in the entire rod then possibly. If the rod is bent or damaged in some way you need new rods. Still, I find it hard to believe you have a rod knock given it goes away right when you touch the throttle. Generally speaking the rods will keep making noise even under load or with acceleration.

 

O.K., now I think I am going crazy. Got home from work, figured I'd crawl under my rover while ideling since the noise always seemed louder from under the truck than from the engine bay.

As I crawled under, I swear it sounded like the knocking noise was coming from the drivers side cat. But being as close to the oil sump it is, hard to tell.

So I grab a hammer and give the converter a couple blows(not too hard). Gone. let it sit a few min, fired it back up, let it idle for a few min. No knock.

Bad converter? If the brick broke loose, it still must be in one piece knocking in there, cause when I tap the converter, I hear no rattling.

 

Happens all the time and not just to Rovers.

 

I've heard of it, never to me though. Had them plug and glow red before.

 

Luckily the cats for these are pretty reasonable. If you have a thermal laser you can check the temp of the cat from left to right. This will tell you if your cat brick is causing back flow in the exhaust. Although it sounds like it isnt. Just another annoying Land Rover Disco issue.

 

I'm gonna look into having a universal welded in, as I can't find a complete y-pipe assembly for under $400-500