Gentlemen, on a scale of 1 to 10, how difficult would you rate these engine repairs?
 

I've had a small from my front crank seal for some time. However, after a 1,100 mile road trip (and adding 1 and 1/2 quarts of oil along the route) last weekend, I'm now finding puddles of oil underneath my W115. If I'm going to tear into it that far, I might as well replace the water pump and rebuild the vacuum pump while I'm at it.

Vacuum pump: seems pretty straight forward and Phil sells both the diaphragm and the check valve kits.

Water pump: I guess the big concern here is rounding off the fan bolts, or so says the Other Guy ™. I suppose that I need both the housing gasket and the actual water pump gasket?

Front seal: This intimidates me. From reading the board, I'll need to pull the radiator, find the correct puller, hope the seal mates properly, and put it back together sans leaks and without the the crank bolt backing out.

Although I can do the basic things on my 240D, the most complicated thing to date has been reinstalled the IP. Everything else (timing chain, valve seals) I've farmed out to my Indie.

How would you gents rate this repair?

Are you sure that ALL of that oil is going by the front oil seal? If it is, EVERYTHING underneath the center of the car should look as if it was painted in oil with a paintbrush or spray gun. Does it look that way?

I'm not trying to be argumentative or give you a hard time. I just don't want to see you do a bunch of work and be disappointed with the results.

Diagnose thoroughly before you prescribe.

As far as the job goes, I've never had an MB diesel engine that early apart. I think it's safe to assume though that the harmonic balancer goes on much the same as later engines. If so, you must take great car in putting the balancer back on. There are two steel dowels that are tricky to get lined up. It is not uncommon for a mechanic familiar with woodruff key arrangements, to just stick on the balancer and impact wrench it into place, ultimately DESTROYING the crankshaft snout. You have to mess around getting the balancer in place THEN push the steel dowels in place.

Best of luck with it.

Assuming this is the turbo 617, have you checked your turbo drain lines/ gaskets? Also check the oil pan seal, mine was leaking pretty bad once upon a time.

The engine in question is a four cylinder atmo unit.

The attachments may help.

Thanks for the input so far, folks.

I'm reasonably certain that it's the front main as there's wetness all around the lower front part of the engine. A small leak was pointed out by my indie before and we ranked it low on the priority list. But now I suppose the road trip aggravated it and my oil consumption/loss has went from 1 quart every 1500 miles to 1 quart every 750-800.

My indie is very reasonable with his rates ($56/hour :D) but given a pending overseas vacation and home repairs my Benz fund is running on empty until the end of the summer. I'd hate to miss out on the next few months of good driving weather so I'm tempted to try it myself.

The hardest thing to do amoung the items mentioned is the front main. The only thing that makes it hard is holding the engine while you loosen/tighten the crank fastener. If you have the $pecial crank lock tool then there is nothing to it.

I seldom will disagree even a little with Engatwork but I agree with Larry here, the hb is very very tricky to install and many a good crank has been ruined by improper installation, necessitating pulling the engine down to replace the crank.

At the oil level of consumption you mention I would not touch it but just add oil and put something under the engine to catch drips when it sits. Are you using synthetic oil by chance? Old fashoned dino oil might be the best choice if you are.

This being a 115 it is not turbo and this part of the motor is essentially the same as the later 616 and 617 motors.

Thanks for the input, folks.

I just called the shop and will probably go that route. Assuming that it's just the seal and that the spacer doesn't need replaced, the reasonable cost offsets the risk of fouling it up.

I'll get to the water and vacuum pumps later since they fine for the time being.

It's not that hard to do if you have the tools. If I remember correctly the pins for the HB are not 180 deg. apart so, I have to agree with LB and engatwork it can be tricky and I have seen many misaligned and ruined. Also, If you don't have a huge pneumatic impact driver with lots of torque removing the front nut is pretty difficult.

I did the Fr main seal in my 617, and yes the dowl alignment is critical and somewhat tricky.
I chased down numerous hard to fix leaks with engine in car, turned out I had a restricted breather, not sure how the set up is on the older cars, but make sure your CC is venting OK.

cc is venting right
 

what is a cc (asks the kid in the back row of the classroom, groggily...) and where is its vent?

crankcase:)

I'd about forgotten about the dowell pins:). Thanks for the reminder ya'll.

In my opinion the ONLY way to re-install the hub is to install it without the pins in, line up the holes (this is actually pretty easy to do) and install the NEW pins. IIRC this is how the service manual says to install it.

Come on bipolardave you've got loads of experience - everything should be a 1 by now!

As for the OM616 / OM617 front crankshaft seal do the cup special tool

PeachPartsWiki: Replacing Front Crankshaft Seal with "Special Tool"

and help me figure out a good way of holding the flywheel in position so you can apply the torque of the planet turning to the crankshaft bolt here

http://www.peachparts.com/shopforum/diesel-discussion/284511-has-anyone-ever-made-good-diy-tool-lock-om617-flywheel.html

The secret to a successful installation is all about tightening that bolt in my opinion.