My daughter's 98 Dicso I has developed an intermittent knock that seems to be in the lower part of the engine. It literally sounds like a rock rolling around. Has $135K and has not had any engine problems. Anybody have any ideas?

 

When does it knock?
Going up a hill ?
On start-up?
Is the check engine light on?

I ask as it could be different things for each.

 

Check Engine light came on 4-5 weeks ago. I don't have the codes with me but they were all O2 related. One was downstream of converter. I cleared codes and they came on about a week later but haven't checked them since then. My daughter called about three days ago and said she was hearing a strange noise. I drove up to her school, cranked vehicle after being parked overnight. Let it idle for probably 10 minutes, no noise. then drove around and started hearing knocking that I swear sounded like marbles. Barely noticeable under hood but very noticable under car laying on ground. Could this be cat converter?

 

Check her catalytic converters by tapping on them with a small hammer and see if they rattle.
When the guts come apart they rattle and it can easily sound like it is coming from the engine.

 

You posted the same time I did...she needs new cats.

90% of O2 codes on a LR are because of the need for a tune up.

 

Does sound like a Cat has broken down on the inside.

 

Thanks guys. I'll get the codes read again tomorrow, make the two hour drive and tap on the cats. The things we do for our daughters! Wouldn't have it any other way! Got a 14 yr old as well that's already lookin' for his LR.

 

Check for exhaust leaks as well.

 

Good, you started 'em off right! :P