The ol' 760-T is at it again- more weird noises. I'm guessing the guru's will get it right off. When idling, fairly loud high pitch noise coming from under the hood. Stops when I step on the gas or when under way as long as the pedal is down. Opened hood but was dark and couldn't pin-point the source, sounds like it's everywhere! Any ideas?? Thanks -J

It sounds to me like your car has a leak in the induction system. Normally those are refered to as a vacuum leak, but your turbo car will have intake manifold pressures above ambient.

To find the leak, let the car idle a whistle away. Use a small piece of vacuum hose to listen for the leak. Put one end of the hose in your ear, and move the other end around until you locate the source of the sound.

John-

Any difference if the turbo is "off-line"? Disconnected because it was blowing off oil before I bought it. Where are the usual "hotspots" for vac leaks on the 760-Ts? What are the other symptoms of vac leak? What damage if you let it go too long? My "engine guy" is 70 miles away. I do brake, body, exhaust and "light" wiring stuff on my cars - I avoid the under-hood stuff unless it's a simple engine! (80's 2 series) Thanks again John.

-J

No difference if the turbo is "off line", whatever that means. The presssure differential between the intake manifld and ambient is greatest at idle, that is why it willl make more noise then.

What did you do to make the turbo "off line"?

John-

No clue how they did it- the guy I bought it from had his shop do it and he doesn't know how they did it, only that it stopped the oil leak. The car had around 150,000 on it when they did it. I called the garage and they remember doing it but would have to look to remember how since the mechanic is no longer there. I plan on having my guy look at it next time up since I'm thinking about bringing it back to a real turbo. Only paid $1900 for it -mint interior, no rust (ex. ding on door, fixing when snow gone.) -J

Also- only does it once car is warmed up. Seems to keep doing it sometimes even while driving although stops for second when revved up- doesn't seem to be the belts- more of a mechanical squeal (like bearings?) than belt noise. Still can't pinpoint even in daylight. -J