Resurrecting this thread - my '87 190D 2.5t started to display the same symptoms - leaking oil from head mating area at #1 cylinder just above the thermostat housing. The car smokes at idle and smells incomplete combusted diesel but runs strong on freeway. I am debating on whether to sell the car as is or replace the head gasket (hope head is good) and continue driving it. The car does not overheat at this point.

I have read through the shop manual but do have several questions on removing the head and hope fellow listers who have done this work can chime in:

- what is the best way to remove the exhaust manifold? Can I leave the turbo on the exhaust manifold and remove them as one unit?
- Is it absolutely necessary to remove the vacuum pump as part of the process?
- How should I remove the chain from the head? Do I grind them open and roll in a new chain or better take off the cam sprocket and keep the chain intact?

Tan
'87 190D 2.5t
'87 300TDT
'91 300D 2.5t

Yes, assuming you can get to the manifold nuts with the turbo in place. You can remove the exhaust manifold with turbo before the head or lift the head with the manifold and turbo attached. Either way, mind the turbo oil supply hard line. It's not all that hard.

Not necessary at all.

Don't cut the chain! Measure chain stretch/elongation before you remove the cam sprocket so you have a reference.

Set the engine to #1 TDC, index the chain to the cam sprocket then remove the chain tensioner and upper guide. This will allow enough slack to release the cam sprocket from the cam. I don't recall if you can pull the head with the chain on the sprocket. If so, zip tie the chain and sprocket and let it fall into the front cover area. If not, remove the chain from the sprocket and let the chain fall into the front cover area. The chain will remain engaged to the crank and IP sprockets and it doesn't have far to go. You can fish it out easily. Basic advice is don't turn the engine until the cam and tensioner are back in place. If you know what you're doing, you can keep tension on the chain while rotating the crank so you can move the pistons to check cylinder ridge, cross-hatching, etc. Count the number of crank turns to keep track of IP timing, or pull the vacuum pump to first mark the cam sprocket.

Even if you intend to roll in a new chain, complete the head gasket job and get the engine running so you keep variables to a minimum. When the engine's running properly, roll in a new chain. The only prep work to rolling in a new chain is pulling the crossover pipe, valve cover and chain tensioner.

Don't expect index marks to align when you turn the engine to verify timing. The number of links isn't a multiple of the number of cam sprocket cogs.

Sixto
87 300D

If it were my car I would check the timing chain for slack and have the pump timing checked as well it may be advanced or retarted which would cause lots of smoke and many new sounds as well . I have a 93 with 200000 as well no issues thus far ,just a thought

Sixto & Coldstart,

Thanks for your valuable advice. They definitely helped clarify things a lot. Last time I checked the chain stretch (50k miles ago) and the chain stretch was 1/2 degree or negligible. This engine has been on Synthetic oil (Amsoil/Mobile1 5W40) since 103,000 miles on the odometer so good chance the chain stretch isn't an issue yet.

If I leave the turbo/exhaust manifold in place and lift the head together, how much weight is there? Do I need an engine hoist or two persons would be able to handle it?

Looks like the turbo oil feed line is bolted down with two screws and would need to carefully watched for when lifting the head. What about the turbo drain lube? Does turbo separate from it fairly easily?

On the special tools - besides the MB head bolt socket 601 589 00 10 00, are there any trustworthy star bit socket set to acquire? Also for chain guide rail pins, would this tool work as well as a slide hammer - BMW Mercedes Cylinder Head Guide Rail Pin Puller Tool | eBay

Tan
'87 190D 2.5t
'87 300TDT
'91 300D 2.5t

Head, manifold and turbo are a handful without help; not just the weight but it's very heavy on the starboard side. I suppose an extra pair of hands will help but some sort of hoist with a way to adjust left-right balance would be my preference. I see no point in keeping the manifold attached to the head so I pull the turbo, then the manifold, then the head. Again, my preference.

Remove the oil supply line and put it in a safe place before you do anything else. In a 603, the clamp that holds it to the block, manifold or engine mount is a PITA to reach. The drain tube has a slip fit between the section that bolts to the turbo and the section that bolts to the block. It'll come off easily but you're leaving a lot to chance to expect it to slide together as you lower head, manifold and turbo in place. Remove the block fitting - you'll need a new gasket - then refit it when the turbo's in place.

There's probably a small bracket between the turbo and the engine mount arm.

No special tools are needed for a 603 besides the 12-point/double hex/triple square bit for the head bolts and something to pull the chain guide pins. The puller in the eBay link is worth the money. It's a tight fit for a slide hammer.

Sixto
87 300D