602 hydraulic lifter replacement (300D 2.5T) - DIY? advice needed
 

Hello. Ive searched for this but I couldnt find anything too relevant. Alot on the 603 engine however.

My problem is, I have a loud "ticky" lifter that comes and goes, and its very annoying (to me anyways). Sometimes once its warm, it will go away, sometimes not. I really just want to replace all 10 of them and silence the ticks. I know that the camshaft has to come out. Can anyone tell me or point me in the right direction on the steps to do this? Im very mechanical, but is this something that should be left to the pro's? Ive never taken a cam out before. Im eager to tackle new jobs. Are there any special tools that are required. Any insight is GREATLY appreciated. A DIY would be great.

Also, how do you tell if the camshaft should be replaced? Visual inspection or is there a measurement?

Thanks for all the help!

Lifters
 

See the PM

I'd like some info as well, as I'll be getting ready to do the same on mine this summer. There's one that just won't shut up even on M1 :rolleyes:

If the M1 won't shut it up...
 

1.'Get the Factory Service Manual (on 2 CDs )
(Mercedes Classic Center,"Google" it or call
1-800-222-0100).You will need it.
2. DIY dooable BUT,You Must Maintain tension on
The timing Chain(and secure the Chain to the
Camshaft Sprocket at the same time)[Hint:
Tie Wraps at least 6 of them.]
3. You must follow the Factory specified R+R
schedule for the "Cam Towers" so that you
DO NOT distort (AND BREAK) the Camshaft.
All the information may be available on this forum,
But the FSM comes in handy forever!
[You're going to loosen the nut securing the Camshaft
Sprocket to the Camshaft,Then wiggle the Camshaft
out Backwards,After removing the Cam Towers,and
removing(thereby slackening...AND resetting)the Chain
Tension(er).]

So if im reading this right, the timing chain doesnt move at all? The cam sprocket doesnt get removed from the cam? Do you removed the chain tensioner? I wish someone had pics...excuse my ignorance...

I did this job last fall. It's not too hard - just take your time and be careful.

Here's an approximate set of instructions. I don't guarantee that they are complete so please use common sense if you choose to follow them.

• Remove the valve cover.
• Slowly turn the engine (using a breaker bar & socket on the crankshaft) to TDC of #1 cylinder (the pointer on the crankshaft should point at the "0T" mark). Don't turn the engine backwards!
• Use cable ties, wire, etc. to securely fasten the chain to the sprocket on the end of the camshaft. Also take a paint pen (or something similar) and mark the position of the chain relative to the sprocket, just to be safe.
• Loosen (or remove) the timing chain tensioner. See attached drawing for location.
• Unscrew the bolt holding the sprocket to the camshaft. You may need to stick a piece of wood or something through the sprocket and brace it against the cylinder head to prevent the engine from turning when you undo the bolt. You don't want to turn the engine when loosening the bolt.
• Remove the sprocket and allow the sprocket and chain to dangle there in place.
• Pick some sort of reference point and note the orientation of the camshaft (for reinstallation later). If I remember correctly, there should be a groove on the end closest to the front of the car that is facing up.
• Remove the camshaft bearing caps as shown in the attached image. This sequence is important and it relies upon previously rotating the engine to TDC as mentioned above.
• Remove the camshaft once the bearing caps are off.
• The lifters will now just lift out. Some sort of suction cup may help, but I was able to just use my fingers.
• The service manual says there's an oil bore you can blow out with compressed air. Apparently you remove a plug (location unknown to me) and blast air through this, which clears out the oil passages leading to the lifters. I couldn't tell where the plug was so I skipped this step without any apparent negative consequences.
• Drop the new lifters in. Be sure they're lubricated (mine were spectacularly greasy from the factory so I didn't add any oil).
• Reinstall the camshaft in the same position as when you removed it.
• Drizzle a small amount of fresh motor oil over the camshaft and lifters to make sure they're lubricated.
• Install the bearing caps, in the reverse order from how you removed them. Be careful here again!! The bearing caps are tightened to 25Nm (18.5 ft-lbs).
• Put the sprocket back on the camshaft. The hex-head bolt is tightened to 65Nm (48 ft-lbs). If it's a 12-point bolt, then it's tightened to 25Nm+90°.
• Reinstall/tighten the chain tensioner, 65Nm (48 ft-lbs).
• Once you're certain everything is in place, remove the ties you used to attach the chain to the sprocket.
• Clean the gasket and cylinder head surface and reinstall the valve cover (10Nm / 7 ft-lbs).

There are no special tools needed other than a variety of metric sockets and a torque wrench.

Excellent summary, Cornblatt. It is imperative that you use Zip ties to attach the chain to the sprocket, or you WILL be sorry. The spring action of the vac pump cam may "pull" the chain into the cavity when the sprocket comes off the cam, don't have a heart attack, that's normal. If it happens, you'll have to yank pretty hard to pull it back up to re-attach the sprocket. Follow the cam bolt procedure carefully or you will break the camshaft. Finally, the oil passage exit is located at the rear of the head, near the top, on the driver's side of the car... there is a small, hex-socket plug that is the rear of the oil galley that feeds the lifters. Remove this plug and blow compressed air into each of the 10 oil feed holes in each lifter bore. You can also poke a paper clip or other small wire into each hole to ensure they are clear.

That said, I replaced all 10 of my lifters last December. This did quiet down the racket, but did not eliminate it, which confused me greatly. A month later, the head gasket failed (visible blue smoke, compression on cyl #1 way low, oil in #1 cylinder). It turned out that the gasket had been failing for a while, and bits of gasket debris had entered the oil galley feeding the lifters. The debris had blocked oil passages to a couple of the lifters! That's why even the NEW ones were noisy!! After a new head gasket was installed, AND the oil passages were fully cleaned out, the new lifters are totally silent (I also use Mobil Delvac-1, btw.) All the photos of my 602 head gasket job are at this link. A couple of samples are below.

http://www.w124performance.com/image...t_failure6.jpg

http://www.w124performance.com/image...t_failure8.jpg

:stuart:

Cornblatt,

Thanks so much for that informative write up. It looks like you covered pretty much everything. I have one question though. When you go to re-attach the cam sprocket to the cam, is that a keyed shaft? I guess my question is, is there a possibility of attaching it back and having it be off by a tooth or two? Does it even have teeth? Do you know what im trying to say?

Also, gsxr, do you have a pic of the oil galley that you have to apply compressed air to? So is there 10 plugs that you have to remove and do that procedure to all?

Also, how do you tell if you need a new cam?

Thanks so much for your help guys. This is all excellent information.

There's only one way to put it on. You can't get it wrong :)

Also, you may feel concerned when you take off the sprocket and feel the slack in the chain, but don't worry because the engine has pins to hold the chain against the IP sprocket and crankshaft sprocket, so it's not possible for the chain to fall off either of those two sprockets. The chain can only get misaligned at the camshaft sprocket, which is why you must securely attach the chain to it.

It's unlikely that you'd need a new camshaft. Check for scoring or wear on the lobes. After 230,000+ miles mine had no noticeable wear at all.

When the cam sprocket comes off, you'll see the pin that locates the cam into the sprocket... it is keyed so it only fits in one position. And it's a pretty tight fit, at that. Align the cam with the cam tower mark - see photo below - these should nearly match with the crank at TDC. You may want to check chain stretch while you're at it (read this TSB), as the early 1990's 602 engines were known to have bad chains. Mine was way stretched when I bought it.

For the oil galley, no, it's a single plug at the rear of the head casting, externally. It will be the only 5mm hex plug in the rear of the head. The 10 holes are inside the lifter bores... you can't see the 10 holes until you remove the 10 lifters. The holes are maybe 2-3mm diameter or so, one little hole per lifter bore, on the driver's side of the head. These are what feed pressurized oil to the lifters when the engine is running.

:o

Lifter R+R
 

cornblatt,

Thank you for the Extra Effort!

Excellent write up!

When I pull the cross-over piped off, is there an o-ring or seal i should replace where it detaches on the passenger side (above the turbo)? There are no bolts there so i assume it just pulls out one you remove the two allens from the other end.

Again, great summary guys, I plan to do this in a few weeks.

There is an O-ring on that side, but these are typically reusable for dozens of R&R's, as long as it's not damaged. They're expensive, so I wouldn't bother replacing it unless it's cracked, torn, or brittle. I also re-use the oval gasket at the opposite end if I expect to be taking the pipe off again, that one also can be re-used at least a few times...

:o

Could you explain how to make sure the engine is at TDC? Does the valve cover have to be off to verify, or can you just rotate the crankshaft until the marks are lined up? I'm sure this is a dumb question but Ive never had to turn an engine to TDC. How many cycles does it go through for one turn on the crankshaft, mark to mark?

Thanks!

Here's what I usually do...

Remove the valve cover.

Get a long breaker bar with a socket that fits on the big bolt in the center of the crankshaft pulley. I think it's something like 27mm (but I don't really remember).

Using the breaker bar, slowly turn the crankshaft pulley in the direction of normal engine rotation. You'll be working against the compression in the cylinders so it may be difficult at times; don't go too fast. On the 601/602, if you look at the uppermost section of the serpentine belt (the part that's easiest to see) it will move from passenger side to driver's side if you're going the right way. See the attached diagram for the direction.

There are timing marks on the camshaft and first camshaft bearing cap (closest to the front of the engine). There is also a pointer and some markings on the crankshaft pulley.

Turn the engine and stop when the timing marks line up on the camshaft and bearing cap, AND when the crankshaft pointer points to the 0T mark. I've attached a few photos...