[SID]

"The tapping is proportional to engine speed (about 7 times a second at idle, speeds up as rpm increases, but disappears at higher rpm - over 2k)

It also only appears once the engine has warmed up, from a cold start there are no noises."


I had the same type of issue with my 96 4.6. The oil had not been changed for a good 30K miles by the look of it so did an oil change as soon as I got the car.
Then the noise started, and got so bad you would have thought it was an oil burner!

So I took the rocker arms off, one set was starved of oil so much that the rocker on cilinder 2 was stuck fast.
Turned out that the new oil had dislodged lots of gunk and that had blocked up the oil ways to the rocker shaft.
I ended up taking the oil pan off to clean out all the gunk, lots of it too, and also the timing chain cover which was so full of gunk I ended up replacing the chain and gears.
The oil pump was just as bad, so did that too.

So I now had what I thought was a clean engine, put two new rocker shafts and all new lifters on, filled up with oil..........no noise

I had a good look at the old rockers a few days later and found that the rocker that was stuck was now ok, so it would only get stuck when hot, two types of metal, different expantion rates I guess.

After 400 miles I looked at the dip stick and the oil was black again, so not as clean an engine as I thought, took three more oil changes to flush all the muck out in the end.

SID.

 

[SID]

Thats amazing the rover ran 30k miles on one oil change :shock: . Be careful with the ATF or any engine flushing agent. On one of my cars I did free up to much gunk and actually caused a ticking noise, as a result of a lifter getting clogged by debris . I ended up continuing the use of the additive until the whole engine was spotless (took awhile) and the ticking noise is still there but considerably less .

Yep 30K dose seem amazing, just a guess on my part as last entry in service book was at 92k and I got it two years on from a guy who seemed to have done nothing to it exept drive, it had 124K then.
Looking back I dont remember the ticking when I first had It, so just the new oil with its detergents was enough to dislodge the gunk. In hindsight I would have cleand out the oil pan before puting new oil in, also would do the rocker covrs, they are a good indictor as to how much rubbish is in the system.

SID.