1999 BMW 750il making an ungodly howling noise

1999 BMW 750LI
85,000 MILES • V12 • 2WD • AUTOMATIC
Avatar
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
1999 BMW 750il with a 5.4 12 cylinder 85,000 miles. I did a tune up on it and now after the vehicle warms up it's making an ungodly howling noise down by the torque converter area. But when you let the motor cool down and start it back up it goes away until it warms up again. What can this be? Is it something I did or pure coincidence?
Oct 12, 2010 at 8:55 PM
Advertisement
Avatar
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
Could be the PCV valves on the back end of the plenum (one on each side) it would make a sound like you described. To check this use a slack tube manometer at the crankcase, more than 6" of difference from side to side and that's where to start. Re post if more help is needed.
Oct 12, 2010 at 8:58 PM