Hello,

I purchased my '84 W123 from the original owner in CA one year ago. The car came w/o the full maint. records unfortunately. It is running very strong but suffers from:
- sloppy steering
- leaking injectors (three), confirmed NOT return lines
- moderate/low blow-by
- more oil leaks popping up

I had done/new: oil cooler lines, trans. cooler lines, motor mounts etc., all new hoses, new plugs, flex discs, bushings, all fluids/filters, valve adjust (very tight), purge, battery, starter, brakes, new return lines (3 times), turbo oil drain, thermostat....
- All cylinders are +300/compression

* My QUESTION is:

I am seriously contemplating a total engine overhaul. I want this engine to be around for another 300K as I am totally addicted... The leaking oil & wet area around the injectors really stick out right now....

In order to have a 100% DRY engine that has max compression & performance - what are the TOP 10 items I should have done (short of a total engine re-build). Is there any reasonable logic in getting a mini overhaul (basically something in between...)?

Thank you in advance for your input & feedback.

Happy New Year (this is the last day I am saying it...!)

__________________
Kieran K
Jersey Shore
1988 300CE (for sale, AUG. 2013)
1995 SL320 (88K) - terrific car
1983 300CD
-1993 400E (sold w/74k)
-1988 560SEL (sold w/49k)
- 1995 S420 (sold w/75k)
- 2005 E320 CDI (sold)
- 2007 E350 4M (sold)
- 1984 300D, sold w/305k, CA car, zero rust & over $12k invested
- 2001 E55 AMG (sold w/81k), I really miss it.
- 1982 300CD (sold, all stripped down)

To rebuild a motor cost a few grand. If you are gonna rebuild it then might as well get all new parts while the engine is apart.

things to do/check:

renew the clyinder sleeves
Check the head for warpage
check the deck for warpage(clyinder block)
New chain-chain is most likely stretched unless it was replaced
Measure the pistons and clyinder walls(new set of pistons are $1000)
Measure the crankshaft and camshaft and see how it meets the specs
new bearings all the way around
check the valve train
New gaskets

Since you are getting 300+ compression then most likely your pistons are fine.

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

100% Dry, at 300 K miles its gonna be pretty hard to get it leak free, there are lots of gaskets that are gonna leak at that mileage, Including Turbo Drain, Valve cover, oil pan, and rear main, and headgasket.

As for the 10 ten list, I would change the injector nozels, you may need to replace the injector hard lines if they are leaking. That should cover the leaking injectors.

I have an engine at 300K miles and the vacuum pump just failed, so I would consider rebuilding that.

Also the timing chain is going to be stretched and could be corrected or replaced.

If you really do want to get 300K more miles out of this engine, a rebuild is probaby gonna be required at some point. To the best of my knowledge no one on the forum is running an original 617 at 600K miles.

__________________
1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

300+ psi- I'd leave it be, get the injectors done, and fix the oil leaks that you can. like the ones mentioned plus the oil filter gaskets(2), and the oil separator & lines. Does the filler cap leak?

the leaks are not too hard to do, but it takes time. the worst one would be the rear main, but that one most likely can wait.

my 317K car does not require oil added between changes. but it is not 100% dry. yet.

timing chain- maybe- but have you measured stretch?
and then there is the thought that if it is stretched, then it has also worn the gears and they should really be renewed as well so they all wear together.

take the thousands you just saved from an overhaul and do the front end and shocks. maybe the rear suspension rubber.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

How hard / extensive is it to replace the Rear Main gasket?
I really think my leaks are coming from:
- oil pan (sump) = easy
- rear main
- manifold area

I would like to have the Head, Rear Main, Timing Chain, Sump & Manifold gaskets all chained...

How extensive is the Rear Main?

thank you,

Kieran-

__________________
Kieran K
Jersey Shore
1988 300CE (for sale, AUG. 2013)
1995 SL320 (88K) - terrific car
1983 300CD
-1993 400E (sold w/74k)
-1988 560SEL (sold w/49k)
- 1995 S420 (sold w/75k)
- 2005 E320 CDI (sold)
- 2007 E350 4M (sold)
- 1984 300D, sold w/305k, CA car, zero rust & over $12k invested
- 2001 E55 AMG (sold w/81k), I really miss it.
- 1982 300CD (sold, all stripped down)

To replace the rear main, will require the removal of the engine.

Turn the engine over, remove the pan. some say to remove the crank.

The seal is a rope type of seal that fits into a groove in the pan and the block.

I was talking to my indiy this afternoon about replacing one for me. He said they are a PITA to do, but he can do it w/o removing the crank.
I will take pictures when we do this job.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Hi - did you ever get pics of this main seal replacement work?

__________________
Kieran K
Jersey Shore
1988 300CE (for sale, AUG. 2013)
1995 SL320 (88K) - terrific car
1983 300CD
-1993 400E (sold w/74k)
-1988 560SEL (sold w/49k)
- 1995 S420 (sold w/75k)
- 2005 E320 CDI (sold)
- 2007 E350 4M (sold)
- 1984 300D, sold w/305k, CA car, zero rust & over $12k invested
- 2001 E55 AMG (sold w/81k), I really miss it.
- 1982 300CD (sold, all stripped down)

I would exhaust all other possibilities before jumping into that one. including running syn oil. I switched, and my car leaks almost no oil now.

did you replace the Valve cover gasket? how about the oil filter gaskets?(one to block, one to sender port) either of these could be leaking at th rear of the block.

pressure wash the engine, then work on leaks. also could be the turbo drain or crank vent drain leaking and blowing back on the rear of engine.
it seems the a LOT of cars leak from the rear main, is it worth it to do all that labor and possibly have a leak return rather soon?


OTOH, if you pull the engine to do the rear main, you could get easy access to all the other leak points while its out. depends on your timeframe and abilities.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

I can't see how you would be able to do the rear main with the crank in place. It's possible you could leave all the rods connected and just lift it up a bit... but you would still need to remove all the bearing caps for the crank.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

A leaky oil filter housing gasket can look like a rear main seal leak. Don't overlook that one if it hasn't already been done. Sort of a pain to do, but not that difficult and very satisfying.

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1983 CD
1958 Studebaker Packard (being resuscitated)

At that mileage you are probably going to need a head gasket pretty soon if its never been done. While you are at it you probably should go through the head and replace the cam chain guides and oil pump chain. There is a very good chance the bottom end is ok though. Also the vac pump.

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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.

No, I haven`t pulled the engine yet. But I do need to get this job finished by the middle of March. will do pictures when we do this job.

Iam in the middle of replacing the clutch in my Datsun PU. have transmission apart to replace a bearing and seals. then a few leaks on the engine while it is out also. then we will get to the MB.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

You should at least check the bores for taper though. The main seal rarely seems to leak on these.

__________________
[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.