Land Rover Repair: engine knock/tap, land rover discovery, piston ring

Question
hi john i have a 97 land rover discovery 4x4 i have a tapping in the back of engine it sort of goes away at around 60 or more but when i park the oil light comes on and the tapping gets loud it also seems as though oil was burning but not so much lately. also when its cold it runs pretty good until it warms up

Answer
Hi Gerald,

could be exhaust valves sticking.  This is a known problem with Series II Disco's.  Carbon deposits form on the top of the exhaust valves ... a valve job is the only fix.

Just to be sure, here's an excellent website that discusses engine noises. He's rough around the edges but what he has to say makes sense.

http://remanufactured-engines.com/page4.htm

Unless you've been brutal to your Disco (I highly doubt this), a regularly maintained series II Disco can expect to have exhaust valve problems starting around the 50,000 mile marker.  

Then again, it could be a freak piston ring that's failed and the noise is the result.  Hard to tell from where I'm sitting.  :)

As suggested above, try using a stethoscope to isolate the noise.  A fully trained LR mechanic would know using the same technique.

Best of luck,

JohnMc