i guess a compression test is in order; not that i could do much about it if i found low compression.... i had been avoiding the test when my motor was running well for the same reason!

i think the latter. it was like a nasty grittiness had been added to the normal engine sound. could any part of the valve assembly make this much noise?

not sure if throwout bearing was replaced. the clutch feel while the problem was occurring was normal.

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'77 240D, 504H, OM617.952, etc.

Did the noise possibly originate behind your instrument cluster ? I had a horrible noise one morning and it got louder and nastier as I accelerated. I thought the worse. Turned out a simple dab of grease on the cable and all was well.

Happened to my wife a few days ago (first sub-freezing morning, she decided to drive the coupe). An unmistakeable sound if you've heard it before. Unfortunately, OP is hearing noise when the car is at idle.

I think a cold compression test is worthwhile at this point.

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'79 240D

If there is any wobble in the flywheel you should be able to measure it with a DTI / clock gauge under the car at the inspection panel just in front of the transmission on the adapter plate.


If you are worried about the valve gear - remove rocker arms and inspect for damage whilst they are out but then remove cog on end of cam shaft so that you can spin cam with out valve : piston interference...

...but that's a lot of work to avoid a leak down or compression test!

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

hmm, no clock gauge yet, but i did pick up a compression tester, which seems to come with an M12x1.25 adapter. have to put the old oil back in now i suppose....

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'77 240D, 504H, OM617.952, etc.

i bought an "innova" brand tester at o'reilly. pulled the glow plugs and disconnected their wiring harness. a couple of things went wrong. here are my results:

cylinder 1: pegged the needle past 300psi. having opened the package and gotten the tool greasy, i wished it had a higher range.

cylinder 2-5: could not get the attachment and hose both installed due to interference on rack position sensor body (2), injection pump (3 and 4), and oil filter housing (5).

i guess i would have been able to continue if i'd had some kind of flexy or right angle adapter in M12x1.25.

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'77 240D, 504H, OM617.952, etc.

Are you sure it is for diesels? Not for gasoline motors?

no, clearly i got the wrong one, the only one they had.... but even one with a gauge up to 500psi would still need that angle adapter. i am running out of time to learn anything here before having to have the car towed. it's been in the same spot for 9 days now and i already got out of one parking ticket.

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'77 240D, 504H, OM617.952, etc.

Do you have a harbor freight near by? Would this have what you need? 12 Piece Diesel Engine Compression Tester

Start it up and drive it to a new parking space. Video the noise when you start it.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Speaking of the noise, did you hear it when you were cranking it for the compression test?

just push it to a different space and remove the chalk marks from the tires if the cops use them....

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"NEW" 1984 300D TD needs some love

i will need several friends and some real luck to succeed at pushing it into another space. no worries, this is part and parcel of using street parking in SF. we're on a slope, open spaces are not nearby, etc.

that said, when i cranked it for the compression test, all i heard was the whine of the starter. there was no fuel introduced so certainly no combustion.

thanks everyone! if and when i try to start the engine i will record the sound.

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'77 240D, 504H, OM617.952, etc.

no harbor frieght nearby. i checked with several places across a couple of counties and couldn't be sure any of them had the 12mm angle adapter, plus all the diesel testers were $200+, so i decided to abandon this step and get professional help from someone already possessing said tester.

of course, the shops i have called are too busy to take it on, and they mostly seem to think taking the head off is a fool's errand, that i should get another 617 and call it a day. however, at this point i don't have a lot of faith in an anonymous used engine. i thought i bought one in great condition and only got 2000 miles out of it! i'm not sure how i should proceed. frustrating.

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'77 240D, 504H, OM617.952, etc.

At the risk of getting flamed, banned, hate mail, physical threats and worse, I'm going to go out on a limb here and make the outrageous suggestion that an old Mercedes just might be the wrong vehicle for you given your situation. With no place to work on the car, inadequate tools, few local resources and other factors working against you, I'd say get rid of the MB for now, get a good driver (Honda, Toyota, or such) and sock the money away so when your situation changes you can get a fine old MB specimen and be able to take care of it in the manner in which you would like to become accustomed.

Or if you really, really, really like the car and are committed to keeping it move out of the city, get a place "in the country" where no one cares if you work on your car, outfit your garage with an array of tools and equipment and wrench away! Make one of your relocation requirements to have a Harbor Freight within 5 minutes away.

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica