Thanks again Barry123400 - Sorry I started a different post, since it was a more specific issue I figures it might be easier to find the answers. Thanks again.

i would never start tearing an engine apart without experienced people telling me that the noise warrents it. you can very easily cause more damage than good if just tearing things apart to look around. this sound is impossible to diagnose over the net. it could be anything from nailing to vacuum pump to a piston coming apart. did you do a compression test? did you pull the valve cover and inspect the valve train?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yes and Yes, Everything looks good so far. At this point it is a 3rd car and not needed. I would have to tow it about 80 miles to a real diesel mech, as I can get by, but no proffesional.

I was out of options without going this far, it seemed with a scope that it wasn't the vp when it was running, but now that I can hear an odd noise while cycling the engine, is making me 2nd guess, which is why I stopped at pulling the head, I too do not want to pull more apart than what is needed.

Thanks

nailing I eliminated by shutting down 1 cylinder at a time, no real change on any of them.

Do you think 1/16th of inch play on the bottom end of the connecting rod is too much???

I found the problem on cylinder #1. Now the question is, do I fix it or junk it???

I guess we will see. Thanks to everyone who repsonded and for the help.

Glad you found it. I just remove the bearings to run my engines so they cannot wear out. Really hope the journal is not damaged. Have noticed majority of complaints seem to be in number one area on these engines. Wonder why? Oil passage sludging up? Fatigue failure of bearing since you mention sudden onset? Bent rod? I would probably just plastigauge # 2 and if within reasonable tollerence just check journal and rebearing the number one rod after making sure oil passage seemed clear. Checking with plastigauge of course.

I was starting to wonder that myself. both of the engines i've seen throw a rod were both cyl 1. what the hell!

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1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

Johnhef, I suspect mercedes knows the answer. Possibly no tech note ever issued because it is basically unavoidable. A little less oilflow or last point lubrication arrives at eventually takes it's toll over time. First engine of this series that I totally take apart will be sure to have a good look. Will report anything that I think may contribute. Same on their diesel fours as far as i can tell. Also suspect green castings for engine block may let front bore run a little off square after casting seasons with time providing just enough to run rod slightly off square with crank. Primary cause being the inability to have metal at same temperature inside mold when pouing for whatever reasons. Not enough to bind but just enough to provide a little more loading on the number one bearing. For years they did not appear to get their casting temperature consistent on their camshafts either as always was number one lobe that wore away eventually and it did not appear to be oil related.

Haven't checked real close, but is it feasible to pull out #1 without pulling head (from below)? If not, no big deal I have already removed everything - again - to remove head. I wasn't sure if the oil pump assembly (once again didn't look real close yet, but I think that is what I was reaching around to check #1) is in the way of dropping that straight down, or if that would be too difficult to replace piston into the cylinder.

If I do too many things, than I might as well rebuild the whole thing, as there are probably a 100 things that may be on the edge of giving in - who knows, but for what I paid, I am just interested in getting it road worthy again.

Thanks again.

I will let you know what I find once pulled out - just for your reference later.

go with Barry 123400's advice,if the vacuum pump checks out O.K.

You may or may not get a metallic screeching equivalent to fingernails
on a blackboard just prior to "Spinning a Bearing" on the crank end of
the rod.

Do not ask how I know.

Thanks for the post, but I am suspicious that you did not read page 2 - I am to the point of knowing that it is the crank end of a rod bearing, if you can help me with my last question that would be great, otherwise - thanks.

Wish someone with more experience this engine type would chime in. If journal checks out I would think you can rebearing #1 rod without pulling head or piston assembly out. Most important is that the journal is not scored up or rough and still appears pretty good. I do not suspect rod end has stretched to any degree. Also try to get a good look at bearing shells to try to determine type of bearing failure that occured. The reason I would try to plastigauge #2 is just to get some indication of other bearing wear and to see if #1 was an isolated occurence. Of course #2 is going to be nowhere near as bad but will help you have perhaps a little more confidence in engine if still not at outer limit of specs.

first, 1/16" sounds like a lot of play. it will probaly be necessary to pull it out and go through the engine. if one is worn that badly i would not think that fixing it alone will solve the problem. the bottom ends on these engines are about bulletproof. we have pulled engines out with hundreds of thousands of miles on them and found the bearings have no measurable wear. usually we put new ones in anyway but sometimes we have not. it doesnt seem to matter, if they mic out.

if you have a bearing badly worn, there is the possibility also of the bearing material getting into other places and causing other problems.

my advice is to pull it out and pull it down to see what is causing the problem. most likely your other bearings are worn too, and the oil pump and the chains and guides, and on and on. bearing failure in the 240 or 300 motors is just unheard of. it probably means at some time it was run out of oil or on very dirty oil or very low oil levels.

i have owned about 30 mb diesels and have rebuilt at least six, having bought them blown up and done the fixing. i dont do it myself but have a very good friend who owns an automotive machine shop. i have participated in the process to different levels through the years but lately have pretty much participated in decision making and writing checks. i found that even though i love tearing an engine apart and putting it back together it comes out much better if he does it.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Thanks for the input, my struggle is that this happened 3 weeks after buying it and I do not intend now to keep it. I have already replaced the vehicle. I pulled #1 and #2, since I can do that without pulling the engine. I am not sure if I can pull the main oil pan without pulling the engine (anyone who can tell me, please do) But there was a major difference between #1 and #2 bearings, there was a little scoring on #2, but #1 was destroyed. I can feel any play in 3-5 using a non-metalic tool to reach them.

Anyway if I pull it and replace everything that needs to be, which I know with 310k on it I will find plenty I am volunteering to spend money that I will not get back....if I do that I am better of junking it between time and money.

I thought if I can get it in runnig condition and everything else looks decent, that someone who only drives 10-15k miles a year. it would not be a bad deal to spend 2500 bucks for a MB that lasts for 2-3 years.

Not sure - a lot of things to consider.

Thanks