I understand there is a problem with the front of the engine block (too thin?) between the timing chain area and cylinder #1 where it cracks and lets oil into the cylinder, not the head gasket but a problem with the block itself. I have zero experience with the 603 engine, but heard from a specialist of these engines who owns a few (and why I don't!).
606 engines are out there for under $1000, these are rusty cars now that can be had very cheap I know of some sitting in the back field retired. We have a few around in Canada, not terribly many but they did rust badly (98/99 E300TD, fewer W140 SD's).

Well, I attempted it last night, but the results were less than desirable. On the third head bolt I attempted, the triple square bit didn't sit all the way down in the bolt and stripped it out. It was getting late, so I decided to call it a night after that.

After looking at pictures of the block, I do not see a way that the front between the timing chain and cylinder 1 bore could become compromised without oil getting into the coolant. I drained the coolant this weekend, and it was completely clean.

As for buying a E300TD and pulling the engine, I do not have the resources to pull that off at the moment, as this is all being done in a parking lot at school, and I am saving up for studying abroad. It might be something I consider after I graduate as these cars near the bottom of their depreciation bell curve.

Thanks again everybody for the help!

Get the MB special tool for the head bolts, way too easy to round out the bolt and then you've got to grind the bolt head off to get the head off so you can deal with the broken bit left in the block. There are bolts outside the valve cover next to the intake ports: clean those out REALLY well. Make sure the tool is fully inserted in each bolt prior to attempting to remove. Get a big breaker bar, and be ready for some muscle work, or get an impact gun. The head bolts are tightened to stretch point, when they finally let go the crack may fool you into thinking you've broken the bolt or the tool.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Got the head off last night and the oil passage was completely shot, so the new one is on the way. It was late when I finally got it off, but I did measure TDC on 1 and 2 and they were within tolerances of the dial indicator, and they were both still heavily crosshatched with no evidence of scoring of the bores, so hopefully that means no bent rod. I will measure the rest of them tonight after I drop the head off to get hot tanked. Also thinking about getting a sandblaster and walnut or almond shells to clean all the burnt oil and carbon off the cylinders as I really dont want to take the engine out to get it cleaned. Also just ordered the Bosio SD314 injector nozzles and a pop tester to rebuild the injectors.

OK, sounds good so far!

The head gaskets come in several thickness, depending on the "deck height" of the head. You may have to measure yourself or have a machine shop do this, if you suspect that the head has been "skimmed" or machined in the past. Get an Elring head gasket kit, or get the kit from MB (which will have Elring parts in it).

Have the same shop clean the intake manifold and cross-over pipe, and probably the exhaust manifold as well if that is also an oily mess.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Doh! Sorry my advice came too late, glad you were able to get past that.

A new set of head bolts was about $70 several years ago, aftermarket stuff. The bolts are stretch to yield, so they can only be re-used if they are not stretched too far; the dimensions are in the service manual.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

I do not suspect that the head has been decked, but I will have the shop check for that and also trueness. It may need to be decked anyways. I have had the intake system sitting in the parts washer since I took them off, but the intake itself may still need work. This whole car needs a good, deep clean after this oil disaster lol.

Oh well, it was just me being lazy and not taking the injectors out.

Also, I have a new set of bolts ordered along with the head gasket. I was tempted to get some head studs, but I think I'll leave that for down the road.

I still need to get me a service manual too.

Yes, you really do need the service manual.... particularly for the unusual procedures like the head bolts....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I've been looking around online for it, but haven't had much luck. I did find a thread though over on benzworld where they have posted a ton a individual articles and one guy has the service CD for download, but I haven't tried it yet. Needless to say, finding textbooks online is way easier than finding shop manuals.

If head needs dressed check that the maximum allowance is not exceeded. Unless there is a slightly thicker head gasket available. You are not allowed much material removal.

The head gasket failure in the oil passage area is not indicative of a warped head in general. More at least to me of questionable design issues. Or the head gaskets just rot out or give over the many long years in some way.

I hope it is not warped, but on an engine with higher miles and a failed HG, I wanted to make sure. I dropped the head off to the machinist yesterday afternoon and the turnaround is early next week, so we will see.

I also purchased walnut shell blast media yesterday to allow me to clean up all the carbon buildup on the pistons and cylinders. After that, I am going to be double checking the piston heights a TDC to make absolutely sure there isn't a bent rod.

A little late on the update here as I have super busy, but there is some good and some bad:

Good:
-Head Gasket was bad at the high pressure oil passage in front of cylinder #1, causing all the oil to leak into that cylinder.
-Cylinder head came back from the machine shop with a clean bill of health
-Measured the TDC of all the pistons reference to the block deck and they all came back within +/- 0.001" of each other, so I'm fairly certain this isn't a rod bender...so far

Bad:
-At some point the camshaft got dropped by one of my friends helping me. I tried to order a used one off of ebay, but the supplier sent an om617 cam instead. Now I am having a very hard time sourcing a camshaft for a 603. They can't be that hard to come by, right? Does anybody have any ideas for a source? I haven't tried the wrecking yards back at home or over here in Germany, but I don't have any tools with me here to pull a cam.

If you are in Germany.... look for some five speed trans for the 617 and 617 flywheels... make a profit off your trip....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I believe that the 603.96x cam is the same, might want to check.

I have a W140 w/ 603.971, and a T124 w/ 603.960(ish), most parts can be swapped.

The 3.5L has less hp, mainly because of the ~500rpm lower high-idle setting in the 3.5L. It also has better fuel curve from the ip (which is why I'm running a 3.5L IP in my 3.0), gives you more power at lower RPM to compensate for the lower max. RPM.

In replacing your headgasket, I am running an ELring 603 HG, and at 18.5psi boost and 50k miles since building the engine I have had no issues (knocking on wood). The headgasket has changed and the new design should be fine, I do not know why you would want to experiment with a 606 HG.

Many people here pull the "sky is falling" routine as soon as you mention a 3.5L, I've owned two and no rod bending, both went past 250k miles with ease. Most of those who claim the engines are weak are owners of 616/617 engines and have never actually had a 603, ...

Hopefully you'll have no big issues. Check the suspension ball-joints and bushings over, make sure everything is tight under the car. Sure there are a lot of electronic items that can fail, but if not abused most of it will last a long time and these cars are beasts, really nice to drive on the highway.

For adding some power, you will find that the vacuum-operated wastegate will try to trip you up. It is the opinion of many (including me) that replacing the wastegate actuator with a direct-acting (pressure opened) wastegate will make life much easier. The actuator can be found on an OM603.970 ('90-'91 350SD/SDL).

I do not know if you can safely increase the high-idle setting, nor if you need to. Some of the simple tricks to add power are to increase the max. fuel settings in the IP, adjust the ALDA (usually about 1-1/2 turns will do it), be sure that the ALDA / boost enrichment is working at all (search "switchover valve" for some help) or if you are good at modulating the pedal to avoid black smoke, many just eliminate the ALDA. If you are adding more fuel, add some boost, my experience is that the (IIRC) Garrett T-30 55 turbo and your IP will match pretty well at around 16-18psi boost, that's about as much fuel as you can supply and more boost is only more heat.

Also check the injection timing, might even try a tiny bit of advance from spec. if you run good (high-cetane) fuel.

Last, do your engine a favor and add boost & EGT gauges. Tells you a lot about the health and tune of your engine, and look cool besides.

You're not going to turn many heads at the dragstrip, 5,500lbs of car just isn't going to jump that fast, but once they're rolling they handle quite well and are a grin to drive.

Best of luck, keep us posted on its progress.

__________________

Gone to the dark side

- Jeff

I never thought about it earlier. If you are in Germany and the car has spent It's lifetime in Europe. My understanding right or wrong they did not experience rod bending there. This engine was designed specifically for the north American marketplace under real pressure from North American dealers. Still many are loose in Europe I understand as well.

None of this has ever been totally verified. Just kind of rumors over the years I have picked up.

This was primarily. A not really that well thought out expansion of the three liter lower block rather than a new engine.

Over bored leaving little material between the cylinder bores. For example when you had the head off you should have noticed it. Compounded by longer piston throws requiring pistons that should not have been used at that period in time on diesels. To get clearance for the stroking.

If you have not gotten a cam yet. If a used one try to get the followers for it numbered and reinstalled in the same location they came out of. There is a tendency well proven that cam followers and the lobes kind of initially wear in an individual fashion. Or become matched to each other if you wish. You might get away with mixing used parts up but if avoidable it is desirable.

You might also post he damage that occurred with the dropped cam. Some things on damaged cams are fairly easy and cheap to repair and others of course are not.

I used a really good place to deal with for example with unnatural serious lobe wear and damage in my gas Mercedes days where they seemed to have a soft cam issue at the front of the engines.