My 350SD seems to have at least one weak lifter.

The symptoms:

When the engine is hot and idling there is some lifter clicking and a slightly rough idle. (It was worse before I changed the injector nozzles).

When the engine RPM is up, and the oil pressure, the clicking goes away and the engine runs smooth.

The car rarely idles because I live in the country and there isn't much traffic and few stop signs.

Now on fixing it:

I found a nice thread on how to test and change (OIL PRESSURE and FLAT LIFTER-603.960) the hydraulic lifters and I have a couple of lifters. My feeler gauge is on the way.

The post says to rotate the crank. What is the best way to do that? What tools do I need?

The post says: "I pulled the cam", what tools do I need for that? How do I do it?

Do I need any tools to pull out and replace the cam followers? Do they need to be filled with oil?

Any other advice for me as I set out on this project?

I will upload some pictures and more detailed instructions when do the job.

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1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

What engine oil do you use? Some say Mobil 1 will quiet lifters but it can take up to 10K miles to [not] hear the results.

Use a 27mm socket to turn the crank by the big bolt head in the crank pulley. Turn only in the direction the engine normally turns which is clockwise as you face the front of the engine.

To pull the cam you have to release the sprocket from the cam, remove the cam tower bolts noting the specific loosening sequence or you will have a DOHC engine, then simply lift the cam off the head. Zip tie the chain to the sprocket, use a screwdriver through one of the sprocket holes to hold the sprocket while you loosen the bolt through the sprocket into the cam. IIRC you can do all this without releasing the chain tensioner or upper chain guide.

A magnet or valve lapping suction cup will remove the lifters from their bores. Mind you don't gouge the bores.

IIRC there's no need to pre-oil new lifters. If you remove the chain tensioner, it has to be pumped/primed in a container of oil before installation.

I haven't read that post but I don't know what you need with a feeler gauge when working with hydraulic lifters.

What's disturbing about lifter tick in a 602 or 603 is it's usually caused by debris restricting oil flow in the journals that feed the lifters, or debris getting to the lifters. The really disturbing part is the debris is usually from the head gasket disintegrating around the high pressure feed port to the head.

Sixto
87 300D

I use Shell Rotella T engine oil. I change it every 3000 miles.

What is IIRC?

What is the specific loosening sequence for the cam tower bolts on the 603 engine?

The feeler gauge is to find the bad lifters by measuring the clearance.

I don't like the the idea of a disintegrating head gasket. Is there some way to find out if this is the problem without removing the head?

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

IIRC= If I recall Correctly or a variation of that..

__________________
hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

IIRC = if I remember correctly

Cam tower sequence = get a manual! Too many specs and sequences to leave to memory of the likes of me

Head gasket = nope. Well, maybe you can remove the #1 and #2 prechambers and check with a borescope if #1 is oilier than #2. That would suggest a compromised head gasket. Pulling the exhaust manifold and comparing exhaust runners might lead you to the same conclusion.

Sixto
87 300D

I was experiencing something similar, a louder tick that would come and go. Last oil change I fished out some very tiny springy bits from the sump pan. Not sure what these are from, but best theory is from a spring that wraps around a seal. My mind immediately jumps to valve stem seals, under a lifter, 'cause that was a recent change in noise from the engine. Thinking I'd blown one of these seals and its crushed bits were plugging up oil journal, less pressure under a lifter, more noise.

Anyone with valve seal experience: Do these seals use a wrapped spring around them? Or do they have one thicker sprung loop wire wrapped around them? Pictures I've seen seem to show the loop but I can't tell for sure if there's a tiny coil spring in that seal at the bottom or inside it..??
These would be on original head, MB parts. .. on OM603.960

Still trying to figure out what the bits in the pan are from..

Talked to my trusty independent mechanic about this. I'm talking about doing all the valve seals with head on car. He says that's a lot of labour on the car, and if you're doing seals and find a bad guide you're going to want to pull the head and take care of guides too. With the mileage on the car, probably needs valve springs too... Now we start comparing the costs of R&R to just dropping a new head installed ($3000). In the end, he said don't rush into this. Car is running well and maybe consuming a little oil... not making the noise anymore. I think the journals have cleared themselves.

__________________
Cheers!
Scott McPhee

1987 300D

I don't find any metal in the oil. I changed it today.

The engine only has about 60K miles on it with a new head.

Is there some way to roto-rooter the oil journals?

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

Not on the car.

Sixto
87 300D

The service manual for my 606 says to never use a magnet to remove the lifters, because they will be magnetized and will attract swarf.

His engine may have different recommendations, but that's still an issue. Unless they're all being replaced, in which case you don't care if they get magnetized.

The diagrams are posted in this thread:
602 hydraulic lifter replacement (300D 2.5T) - DIY? advice needed

If you're in a hurry and don't want to read that whole thread, engines 601 and 603 are in this post:
602 hydraulic lifter replacement (300D 2.5T) - DIY? advice needed

And the 602 is here:
602 hydraulic lifter replacement (300D 2.5T) - DIY? advice needed

There's a plug on the rear of the engine you can remove, and then you can blast compressed air through to clear out the oil passages to the lifters. The details are in that thread I linked to above.

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1989 250TD Wagon 5-speed, 160,000mi ::: Dark gray metallic / black cloth
1984 190D-2.2 5-speed, 287,000mi ::: Silver-blue metallic / black MB-tex ::: SOLD

I had to do some research. The 602/3 sections of the W124, W126 and W140 manuals say to use a magnet to extract lifters. The M119 (DOHC 4.2 and 5.0 liter V8 gasser) sections of the W124 and W140 manuals say to not use a magnet. I don't have a 606 manual but I'll take your word for it.

Sixto
87 300D

Note that there are corresponding instructions for installation/tightening!

Sixto
87 300D

Thanks for all of the good information. I will let you all know how it goes.

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside