Hi all, I hae an LT 2.5, 5 cyl TDi. 40,000 miles.

It has recently developed a "tapping" noise which I can hear all the time.
It sounds like my old transported when the valve lifters needed replaceing, only not as bad.

It sounds like only one of the lifters is tapping, so my question is;

1) How long should a set of lifters last,

2) Why is it only one that's tapping, oil feed prob??

3) How easy is it to replace the lifters?

4) Would an engine flush help, or make things worse?

Any help appreciated, thanks.

Robert.

PS: does anyone know where I can get a workshop manual for the LT 35 TDI ( 2003)?