RE: 4000csq valve tapping gone possible cure

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

> by the oils department. Looking down I saw a bottle of STP oil treatment,
> so
> I bought a bottle. It has been 3 weeks since my last oil change and the
> valves on the 4000 were tapping quite loudly. So I decided what the hell,
> I
> would sue STP if the engine blew up ;] then drop in a MC turbo engine.
> Well
> I poured about 3/4 of the bottle ( the stuff is like slime) and half a
> bottle of oil. The next morning I was a little worried to start the car
> up,
> but cranking it up and no more tapping. It has been a full week and about
> 800 miles  with still no tapping.???
> Has anyone else tried this because I am usually very skeptical about the
> snake oil/ techron additives/oil cleaners but this seems to have stopped
> the
> noise.
> 
... not sure I would consider Techron in the snake oil category ... I
personnaly just buy gas that already has it in rather than to buy the
bottles ...

There are a number of products out there that you can add to your oil to
quiet the lifters.  From my single experience with the '88 5kCSQA at first I
could tell when it was about time to change the oil when the lifters would
start making noise.  I tried some stuff from Berrymans which did the trick
almost immediately ... quiet lifters!  The way this stuff was meant to be
used was that you put it in before you changed the oil and drove it around
for a week or so and then changed the oil.  After I changed oil things were
still quiet, but I found that over time the noise got louder, sooner after
the oil change.  It finally got to the point where I replaced the lifters
... problem solved.  

BTW, Audi has some TSBs on this subject as well, and there is one about
replacing an oil return valve on the spark plug side of the engine.  This is
for the MC, but it may apply to other engines as well.  I replaced this
valve to no effect ...

HTH!
Steve Buchholz
San Jose, CA (USA)