Not to toss goo into the ointment here, but a serpentine belt can make a
clicking noise that sounds just like a tappet. The problem may not be
anywhere near as serious as you are thinking.

I can't imagine your car having sticky lifters at this early age. If it does
in fact have lifter problems, the odds are very good that a chemcial
treatment will fix it. When I was a kid, it was common practice to used a
pint or so of automatic transmission fluid in the crankcase to free sticky
lifters. The problem in those days is largely gone from the picture, but
tarnish from the oil would clog the passages inside the lifter, and prevent
the moving parts from moving freely. The ATF is highly detergent, and would
clean the tarnish, allowing the lifters to operate freely again.

Today, they use stuff like Marvel Mystery Oil to accomplish the same goal.

Usually the sticky lifter will free itself as the motor warms up. If yours
continue ticking, then I'd be looking at the belts before the lifters. There
is Belt Dressing that can be applied, but the belts should probably be
replaced.




"Paul Aspinall" > wrote in message
. uk...
> Hi
> I have a 2000 740.
>
> I have owned 2 previous 740s, and a 745Li.
>
> None of my previous cars have had this behaviour that my latest 740 has
> developed.
> At idle the car seems to 'tap / tick'. This is noticable up until about
> 2,500 rpm, where the noise gets drowned out.
> I had the car at my local dealership last week, and they said that they
> couldn't hear anything wrong. However, I am now convinced that the 'tick'
> shouldn't be there. A friend of mine is a mechanic for SAAB, and thinks it
> may be one of the hydraulic tappets... (?)
>
> I can particularly hear the noise when the climate unit is off (ie. no
> other fans blocking the noise), and sat in the drivers seat with the
> window down.
> I've listened with my head under the bonnet, and it definately seems like
> there is a tap from the left hand bank of 4 cylinders (although it may be
> something else). However, the noise is definately from the left hand side
> of the car when facing it (ie. the right hand side, when sat in it).
>
> Something which may (or may not) be linked, is that there is an 'oil spot'
> on one of the cylinder head bolts, on the left hand bank (ie. the noisy
> side)
>
> Has anyone else had this problem?? Can you suggest what it is??
> My BMW warranty expires on Sunday!!! but the car is booked back in to the
> dealership tomorrow, so I am going to insist they look again (as they said
> that nothing was wrong when the car was there last week).
>
> Any help / advice appreciated.
>
> Thanks
>
>