I'm going crazy! My turbo is silent until I hit 60mph, whereupon it suddenly begins making a shrill coach-whistle sound. If I accelerate it vanishes, if I go slower it vanishes. If I cruise from 60mph and faster steadily it's there screeching away under my hood, amazingly loud. I think it's the wastegate as it's not a bearing noise. What would make a wastegate sound like a coach-whistle? How do I replace it? I looked at a removed turbo at a shop, the gate seems to be impossible to remove, four screws on the back remove a cover and gasket revelaing a slot sized for a huge flathead screwdriver. If I turn the slot it rotates the top half of the gate. I also noticed the gasket that I removed from the back plate was split inside. Could this be why my wastegate is whistling?
If it helps, it's a 81 300SD. Please feel free to reply to my personal email: snipped-for-privacy@hotmail.com. Please remove the obvious spam-foilers. I'll check the group too. Thanks!
Doug