first oil change, now weird noises...

[Fred Munro]

Hi Pat;

This may be a crankshaft seal leak, either front or back. At idle the
engine's PCV system pulls a fairly high vacuum on the crankcase. If the
seals are weak, air is sucked past the seal into the crankcase, creating
the howl. As the seal warms up it gets more flexible and usually seals up
enough to stop the noise.
When it is howling, try pulling the oil dipstick up a bit. This allows air
into the crankcase down the dipstick pipe and breaks the vacuum. If the
noise stops or changes in pitch, it's caused by a leaky seal.
I had a similar howl on my previous 200q which happened only in winter when
the car was first started. It went away after I changed the front crank
seal.

HTH

Fred Munro
'94 S4

-----Original Message-----
From:	paanta at splatterfish.com [SMTP:paanta at splatterfish.com]
Sent:	Friday, August 16, 2002 8:28 AM
To:	quattro at audifans.com
Subject:	first oil change, now weird noises...

All,
  I finally got around to replacing the oil on my "new" 140K mile old
5ktq.  Last oil change was one owner back, so I was anxious to get it
done.
  I switched from castrol synth/dino blend to Mobil 1 15w50.  At least,
I'm told it was the castrol blend.
  Not knowing _exactly_ how much oil the car takes, I put in ~4.9
quarts.  This overfilled it maybe 1/8"-1/4" over the max fill line.
  Since changing the oil, I get a squeal/howl/scary noise from the car.
It starts howling about one to two minutes after startup and goes
away after maybe 15 minutes when the car is good and hot.  It
makes the noise at idle, and its slightly worse as engine speed
increases.  I think the best way to describe it is the sound you get
from rubbing your finger around the rim of a crystal wine glass, but
much lower pitched and more intermittent.
  Question is...is it angry because I switched to mobil 1 15w50 (too
thick??), or is it angry because I overfilled it slightly?  WTF is this
noise?  Is it permanent??  The car runs otherwise just fine.

  -Pat