Flatlander1961

I just got an 85 300D. When I accelerate, just before the turbo kicks in, I hear a high-pitched noise. It comes back when I let my foot off the throttle. I mostly hear it when I lift off the foot feed slowly. If I take my foot off quickly, I do not hear it. I cannot re-create this while stopped, it only happens when I am driving. Any thoughts would be appreciated.

dogbite5150

Hmm. I'm thinking driveline. Perhaps the u joint? Just a guess?

Flatlander1961

Not sure myself, you can barely hear it on the acelleration, you can't miss it when you lift your foot off the pedal. Car runs and drives great.

JSe420

check to see how much play you have on the long side of your belt

Flatlander1961

Belts look good, it is not a squeal, it is almost like a whistle. I have heard the turbo oiler can go bad and give you a noise like this, but it only does it before and after I feel the turbo kick in. And I have no experience with a turbo diesel. It is most pronounced when I lift off the throttle. Also have a vacuum leak I have followed to the large diameter black line running into the firewall. I have 4 seconds of vacuum to lock all the doors.

dogbite5150

Vacuum leaks can defiantly give you a high pitched whistle. Maybe an HVAC line is disconnected in the dash? Even that leaky line at the firewall could do it.

Flatlander1961

The middle vents don't work. Is there a way to check the oil supply to the turbo?

dogbite5150

Not sure about the turbo oil line. My car's middle vents don't work either. That I believe can be accessed through the glove box.

tanktube67

U-Joints will make the car vibrate

tanktube67

I think you may have a air leak at the turbo hoses or on the aftercooler.