hello, first off I'm new here, was searching the internet for a fix to my new to me 1970 mercedes Unimog with a mb OM352 engine. I'm also over at benzworld

Was a fresh rebuild when I bought it, the injector feed for #2 cylinder was loose it turns out, on the drive home it pumped the oil sump full of diesel. (it's under the valve cover)

ran decent, couldn't hear it miss a beat. heard it make some strange noises just as I got to my street, shut it off, towed it home. there was 3 inches more oil in the engine then when I left for home, a 5 hour drive, and a lot dripping down the front of the engine and sprayed all over.

changed the oil and fired up, no noises at idle, some at higher rpms. I retorqued the cylinder head and adjusted the valves as the sounds sounded more like ticks, now it smokes and makes a regular hammering sound, but doesnt seem like every revolution, only every other, making me think it's something to do with that #2cylinder. Again, i could be wrong. Felt the exhaust manifold, 2 seems a lot cooler then the others.

I was told leaky injectors make horrible sounds, I'm thinking tomorrow i'll pull and swap 2 and 6 see if problem moves over.

Could the injector or pump have been damaged by 2 not having any pressure in the lines? took 5 full turns to tighten the fitting

Is your IP lubricated by the pressurized Oil Sump system?

Your problem is that you (Un Be knowing stly) ran your engine ,Which was using
a mix of Diesel and Lube oil in the Sump.[Diluted Lubricating Oil]
(Diesel does have great Lubricating Properties when compared to Beach Sand...
But,Compared to Diesel rated oil, it Ain't worth squat.)

Enjoy whatever Bearing surfaces are left as long as you can.
(50W150 Oil ?) [Bad Joke]

Then Cogitate about:
Reman Yourself
Professional reman (Noell's in Orlando or Metric in California)
A nice used ,but not abused engine.

I'm gonna repost this over on the Unimog section,with a request that they reply to you over here.

http://www.peachparts.com/shopforum/showthread.php?t=273904

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'84 300SD sold
124.128

I did the same thing with a big CAT engine, ran a few gallons over full on diesel, went into run-away on diesel fuel in the crank-case. Had to stall the engine with the brakes on the freeway in Chicago.

In the end, changed the oil, pounded the injector line shut for the trip to Milwaukee, replaced the injector, that was in 2001 and the engine still idles around 100psi of oil pressure. The CAT manual covers it, isn't recommended nor terminal.

If your oil pressure is good, starts like before (compression good), sounds like you have in injector problem possibly.

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Gone to the dark side

- Jeff

I did an internet search.
Looking at the pic partly explains how it happen as the Injectors and the Return Fuel System are under the Valve Cover.
The other pics I found in my Trade School Text Book.
The Red Arrows indicate areas that are leak prone. Besides that the Injectors themselves can leak between the upper an lower halves just as Mercedes Injectors do.
Most likely cause just like Mercedes is the Return Fuel System.

Attached Thumbnails

     

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84 300D, 82 Volvo 244Gl Diesel

I forgot to mention that if a Shop did the Rebuild you should be able to hold them responsible for any damage. They were supposed to make sure this sort of thing did not happen.

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84 300D, 82 Volvo 244Gl Diesel

the shop rebuiltiti for the previous owner, called them Friday, waiting to hear back from them.

I know it was #2 injector fuel line as it took 4 turns to tighten the line. This engine in various forms can give a lot more power so I was hoping the bottom end stayed in one piece, I'm still going to try to pull the pan and have a look but oil pressure seems fine, if the gauge works properly. I'm sort of suspicios the oil light never came on when I was driving

My concern right now is the injectors or the pump as i never worked with them. could either give loud hammering noises?

the plot thickens, the oil pressure sender also had the water temp wire on it, causing me no oil pressure without engnine running and full pressure engine running as well as full temp running. I took the temp wire off, now I cant get the oil gauge to move, shold show full pressure (3) with wire off sending unit.

A 352 is pretty noisy anyway. Suggest leaving pan on FOR NOW and do other testing and inspection first.

Readjust the valves. Maybe one wore in/out.

Get a mechanic stethoscope. Find which injector (tough with cover on) or delivery valve is wacky. Remove inspection plate on front of engine housing to easily inspect IP drive gears for wear.

Often a 1/8 MNPT gauge, while tapered, will screw into the sender hole and only weep a tiny bit. A mechanical gauge will allow pressure verification independent of elect problems.

Good luck on this bummer deal. Lotsa rebuild ducats hazarded by careless final assembly :-(

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James Marriott
2003 Buick Regal
1983 300D (228k, frau Auto)
1996 Suburban K2500 (192k, 6.5 turbo diesel/4WD towmaster 10,000)
www.engineeringworks.biz
1987 300SDL junker 170k
1982 300SD junker, 265k

Is the Engine still knocking after the Fuel Injector Line is tight on the Injector. As, you would expect it to be noisy when the was not tight as no Fuel was being injected into that cylinder.
I do not think there is anything in the Fuel Injection Pump itself that could cause a loud knocking.
I have seen instances were inside of the Fuel Injection pump the little Gear that makes contact with the Fuel Rack (that is a collor) has split or the screw that clamps it in place has cracked. When this happens you lose control of the Fuel on that cylinder.
If your Fuel Injection Pump Has a Cover on the side. you can remove the cover and watch to see if all of the parts move together when the Fuel Rack moves.
You can also see if any Tappet/Plunger Return springs are broken.

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84 300D, 82 Volvo 244Gl Diesel

it idled better before the head was retorqued and valves adjusted. will get a new feeler gauge and redo.

still no working oil pressure gauge, working on that. none of the alarms work either

edit: I got the instrument cluster apart, the printed line wore through from the cluster so I had 12V when checking with a meter, 0V when the oil line was connected. ANyways, soldered in the missing tracer looks like it'll work, just need to assemble