I am the new owner of a 1987 diesel with 163,000miles on it...the dealer who always maintained it told the origianl owner(my dad) that it wasnt worth changing the timing chain...a bad idea to open it up..would cost more than it was worth. I took it to a new guy who told me i should DEFINITELY change it ...and it will then run for many more miles....who do i believe? my cynical self cant help thinking the original dealer wanted it to die so my dad would buy a new car.....which he eventually did....yet my new guy it seems would be motivated to want to do some work $$$ although he seems like a very upfront honest kind of guy. Does anyone know what the standard thought is on this? or what mercedes actually recommends? I would appreciate any info regarding this. thanks

The 87 has a 603 engine, timing chain isn't a big deal, but they usually don't wear that much.

Specs call for the "stretch" -- actually the wear on the pins that makes the chain longer -- to be checked periodically, with the chain being replaced when the stretch is 8 degrees or more of crankshaft rotation. Fairly easy to do (less easy on the 603 than on earlier engines).

The 603 should run forever, with replacements for cracked heads -- the head cracking, especially if the engine gets overheated, is the only serious problem these engines have.

I'm quite certain the dealer wanted your dad to buy a new car. No money in service, no commission for the salesman, to keep one in good shape. Besides, its worn out anyway, right? SL's with 500,000 miles with no work aside, I suppose. MB engines, if serviced by the book, simply don't wear out.

The car is worth about $6000 in good shape, maybe more, so the dealer is blowing smoke -- an engine rebuild would be required to cost more than the car is worth. Unless you are using huge amounts of oil and the engine clanks, you won't be spending that much to fix anything!

Get the chain stretch checked, replace chain if needed (chain is about $150, takes an hour or two of labor to change it), engine will be like new.

My 87 300D (176,000 miles) uses about a quart of oil in 6000 miles (it leaks a bit at the front cover), runs like new, and has zero problems. I think it was overheated -- new radiator and probably new head when I got it, no service records with it -- body is in excellect shape, I expect to drive it for at least 15 more years. My 1972 280 SE isn't in terrible shape, previous owner neglect included!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter, does the factory not offer an 'offset' key for that engine ....like the one for the 617 ? to bring a slightly stretched chain back into compliance with respect to the valves and ip ?

I replaced mine at around 270,000 miles and there was over 13 degrees of stretch. If I were you, I would change it at around 200,000.

leatherman:

I'd personally put in a new chain rather than mess about with offset keys, if they are available, for the simple reason that the injection timing will still be off, and if corrected, will be off again when the chain is eventually replaced. New chain fixes both, and the 603 chain won't usually wear very fast, if what I've seen and read is true. Rapid wear is usually a result of poor previous maintenance.

But then again, I tend to be a purist. Better to take the more expensive permanent fix rather than the inexpensive "shortcut" and end up with more work later....!

That's why I'm installing new rotors and caliper kits on the 72 280 -- maybe not really necessary, but I feel better having tip top brakes in a fast, heavy car.


Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter, You mean this engine does not have a way to adjust the injection timing relative to the crank position ? I don't understand... something seems strange .... if they offer an offset key from the factory.. that it would not address the ip in addition to the valve timing...

I only brought up the offset keys because it might be much less job than a total chain replacement given the relatively low mileage on her engine...

I would like to take issue with the quality of the offset key fix you imply... it is listed in the factory manual as a fix at a certain amount of stretch,,, and it is perfectly legit from a mechanical standpoint... it puts off, but does not change what will be needed at some point...

leatherman:

Nothing wrong with using the offset key, excpet that it doesn't change the (also late) injection timing, that has to be done separately. Then, when you run out of offset keys (chain too long), you have to change offsets back to zero, install new chain, AND reset injection timing. If you have significant change stretch, why not just replace the chain? Same amount of work as changing the key, and solves both problems for the price of the chain.

On the V8s, offset keys are much more common -- the chain is so long (it goes down behind the water pump and back up) that it is not unusual for the cams to be off enough relative to each other that the right one needs an offset key when the left one (short side of chain) is fine. I'll be checking the 280 shortly (ye gads, ANOTHER part to buy...)

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

1. Until the chain stretch is measured we don't know if she has " significant" stretch... right?

2. the injection ought to be set once in a while anyway...

3. " same amount of work"... ? That seems hard to visualize... why would swapping a key be the same amount of work as installing a new chain ?

To replace a Woodruff key, you have to remove the cam gear. To pull a chain through, you only need to grind off the swage on a link, break chain, attach new one with pull though clip, turn engine until new chain is completely installed, and swage the link down. Doesn't take much longer. You have to remove the belt tensioner, belt, and front cover either way, and get them back on, probably takes twice as long as rolling the new chain in.

Injection timing only changes due to chain stretch.

Hans has not replaced a 601/602/603 chain yet.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

My tech said to check the stretch would cost more than half as much to replace the chain, so I decided to just have it replaced and not worry anymore.