Engine noise

[Joe Edwards <edwardsj@apci.net>]

I have an 88 Audi 90 with 70,000 miles, 5 speed trans.  I'm getting a  
loud intermittent clicking noise in the engine that I'm pretty sure is 
lifter noise. It usually occurs when the engine is first started, 
although I have heard it after I've been driving the car for a while, 
and there are times when the car has been sitting all night and it 
doesn't make the noise when I start it.  The local dealer sold me an 
adapter (small valve that looks like a tire stem) that is supposed to 
fit into the block in the hole where the oil sensor screws into. This 
was a modification covered by a service bulletin that is supposed to 
keep more oil up around the cam and the lifter. Anyone had any 
experience with this, I'm having a hard time getting the adaptor in.
Thanks,   Joe Edwards