Mercedes mouse,

Usually squealing comes from outside the engine. Check all the things connected to the fan belts and make sure they turn easily.

Take off the valve cover and see if anything looks broken such as the chain or cam towers.

Turn engine by hand by using a deep socket on the crankshaft pulley bolt and see if you can hear anything unusal.

If chain is not broken, check the cam timing by turning the cam to the timing marks by turning the crankshaft and see if the crankshaft is near the zero mark.


P E H

Timing chain: 1981 300 D
 

While driving on the highway, my 1981 300 D suddenly lost power and the engine died. It makes a loud squeal and seems to stop short when I try to start it. The loud squeal comes from the top of the engine at the front, and I strongly suspect timing chain problems.

Just wondered if anyone has experience with this sort of thing and can comment. Although I haven't disassembled anything, it sounds like I may be in real trouble here. Is there any way of checking the lower pullies, tensioners, etc. without pulling and disassembling the engine? The Haynes manual makes replacement of the chain sound like a two man job, and that means the shop as I have nobody here to help with it.

If so, does anyone know of a good shop that does diesels (other than dealer) in the Cincinnati vicinity?

Honestly, I don't think you have t-chain problems. Start by taking your belts off one by one, sounds like a belt squeal, making something seized up. If the t-chain broke you would not be getting any fire!

I'm trying to thing of what could cause such a noise AND cause the engine to not start.

I would start by pulling the valve cover and turn the engine by hand and look for cam rotation. If it rotates, I would check start of delivery.

Good luck,

I'm with Brandoncrone, I bet you seized you ac compressor or even just the pulley bearings for when the unit is off. Or something along these lines.