QuestionThere is a constant tapping noise coming from the right side of my engine. It sounds like lifters to me. I took my 98 Discovery I LSE to a Land Lover dealer and the guys there told me it was a rocker arm or rocker. They want to charge me $1000 bucks to repair it. I guess my question is, what particular sound does a lifter make when it has gone bad or needs to be ajusted? Is there a particular sound that a rocker arm or rocker makes when it needs to be replaced?
AnswerHi Bobby,
I've been told that there a LR service bulletin about this problem dated 29.04.98 Bulletin No 0009 and CD. Ref:(?) L8428bu.
It's covered V8 engined Range Rovers from VIN WA 382672 - to VIN WA 391018, Discovery's WA 753113 -WA 769495 and
Defenders(carbed only) VA131591 -WA 140244. If the LR dealer says this applies to your Disco, they are probably right. Most LR owners say this happens on high mileage Disco's more often.
There are other owners who claim that specific rocker arms (they are numbered when cast) are bad. Cast numbers (last digits) r: 17 or 18 or 19 or 20. The numbers are on the side of the rocker arm. This is news to me.
One owner suggested that it could be an exhaust manifold gasket with a slight leak.
I would imagine a tappet job would be more expensive than the rocker arm job that LR quoted. Have you tried flushing your engine oil with some commercial oil flush products? If its tappets, the flush will help reduce the noise for awhile. Its the non-mechanic way to determine if its your tappets. I've heard of an owner who added 500ml of ATF fluid to his oil, ran the engine for 10 minutes then flushed the oil with a commercial flush product. Noise was reduced and helped him isolate the problem to his tappets.
Tappets: high pitch ticks
Rocker arm: clack sounds
For $1000 you should expect LR to do the following:
Disconnect coil wire.
Remove air cleaner and inlet hose.
Clear a path to remove the valve covers
Remove spark plug wires and valve cover hold down bolts.
Remove valve covers. Clean them and set them aside.
Remove stock rockers, leaving pushrods in place. Don't let pushrods drop down into engine.
Install rockers arms and sure-lock nuts.
Ensure the pushrods are still seated in the tappets. DO NOT TIGHTEN DOWN NUTS.
Turn engine over (may require another person) so that cylinder you're adjusting has both the intake and the exhaust lifters on base circle of cam (rocker arms should be level to each other.
Adjust sure-locks down until clearance at pushrod is zero, then crank down sure-lock a 1/2 to 3/4 turn.
Lock down Allen-head screw into sure-lock nut.
Repeat steps rocker adjustment on each cylinder individually.
When all cylinders are adjusted, pre-lube the rockers with engine oil.
Reinstall valve covers and valve cover bolts.
Disable distributor and turn engine over to pump up hydraulic lifters. Enable distributor.
Start engine and let idle at normal speed.
- taken from an ASE mechanics manual.
Best of luck with this,
JohnMc
