PeachParts Mercedes-Benz Forum - View Single Post - 84 300 CD suddenly making HORRIBLE noises and running VERY rough

rcounts · #11 09-12-2008, 10:35 PM

Quote:

Originally Posted by GRIESL

Has timing chain been replaced ever?

I hate to say it, but it sounds chain, valve, bottom end related. I would stop trying to run it and at least take the valve cover off and check out what's going on in there.

Thanks for the suggestions, though as Brian implied your suggestions are a bit of a "shotgun" since they are indeed separate sub-systems in the engine. I will be removing the valve cover though - for sure. The valves were adjusted recently and the chain stretch was between 2-3 degrees and the guide looked good, so I'm thinking that isn't the most likely culprit - though I'm not ruling it out.

Bottom end is a possibility, though it seems odd that it would go from A-O-K to total crap so quick with no apparent cause (like a blown headgasket letting water get into the oil or something). Like I said it was a little low on oil, but not enough to significantly lose oil pressure or anything.

Valves seem like a possibility - only thing I can think of is if one wasn't quite tight enough after we did the valve adjustment - though that was over a month and 1000 miles ago.

Quote:

Originally Posted by GRIESL

I doubt what you have is a bad injector or two--they don't tend to fail all at once. Injectors also don't cause squeaking sounds. When you had the oil filler cap off, did you notice any unusual combustion gases escaping?

I would also look in the air filter and see what's going on in there. i.e. oil, clogged.

I sympathize and wish you the best of luck.

Like I said, the squeeking may just be due to the rocking motion of the rough running engine - and may or may not have anything directly to do with anything internal.

What Brian said about the effects of water in the fuel sounds like injector damage can happen pretty quickly - under the right conditions. BTW, doesn't 15-20 miles sound like about the right distance to burn up all the good fuel already in the IP, filters, and lines, and start getting the bad fuel from the tank?

I was also wondering if anyone can explain to me exactly what is happening when an injector is "nailing"? All I know is what I've read around here - that when one is really nailing it can make a very BAD noise...