Clearly, there's the obvious after the fact method (which I want to avoid), but I'm trying to determine when you know it's time to get it done. I'm driving a '91 560SEL on the weekends once or twice a month - probably about 200 miles max a month. She has 148,940 miles on her.

After she's been sitting for a bit (usually two weeks at a time), when she starts there's a pinging noise that I've been assuming are the valve lifters or something similar as it usually goes away when she gets warmed up. This morning though, that 'valve' noise has hung around. I drove her about 12 miles this morning and it was still 'pinging' (like that noise from low-octane fuel) when I turned her off.

It suddenly dawned on me (and since I don't know any better) that this might be the timing belt telling me she's ready. Thoughts?

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Craig

2011 e350 Wagon < Grey on Grey/Brown. I kind of think I'm cool driving around in this thing, but I know I'm wrong.
2007 e350 4Matic Wagon < Black on Black
2003 e320 Wagon < Black on Oyster. Dog Hauler. Replaced at 170k. Great car!
1990 300SE, Black on Black < Totalled
1991 560SEL, Black on Black < Current, sits around a lot
1972 280SL < Sold, but not forgotten.
1972 280SEL 4.5 < Gorgeous car. Lost to a freak accident.
1985 300TD < "Merzilla". Put 300k on her.

Belts are for washing machines, not a MBZ engine. They use chains.

Sounds like a stuck hydraulic lifter.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

that was funny, thanks for the answer...

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Craig

2011 e350 Wagon < Grey on Grey/Brown. I kind of think I'm cool driving around in this thing, but I know I'm wrong.
2007 e350 4Matic Wagon < Black on Black
2003 e320 Wagon < Black on Oyster. Dog Hauler. Replaced at 170k. Great car!
1990 300SE, Black on Black < Totalled
1991 560SEL, Black on Black < Current, sits around a lot
1972 280SL < Sold, but not forgotten.
1972 280SEL 4.5 < Gorgeous car. Lost to a freak accident.
1985 300TD < "Merzilla". Put 300k on her.

Probably one or more stuck lifters, but a MB V8 likely could use a chain at 150k. They have really long serpentine timing chains, yes? More links on the chain, the more elongation will occur, am I right? The more elongation, the harder the tensioner works to keep the chain taut, etc. etc. If the engine was not abused and had frequent oil changes I would wait until 200k to change the chain. That's a major job on a V8.

Start using some good synthetic oil in it. After a while it sort of makes the noise go away.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

at 148k miles, it has probably had a new chain by now. they tend to break about 125k. i would pull the valve covers and make sure it's NOT a chain making noise. wouldn't want it to break. means bent valves on the drivers side and lotsa money. without hearing the noise, i'd say the previous post is PROBABLY correct. whenever i see 1 of those engines for the first time, especially at or beyond 100k, i pull the covers and check for chain stretch. good luck, chuck.

The problem is not usually the chain, but the chain guides. Especially the ones on the left side (Drivers side here in the US). The guides get old and break. A piece of the guide falls down and jams the chain. The cam gets out of time and it bends or brakes the exhaust valves in the left head. You are looking at 3 to 4 grand to fix it correctly. A new chain and upper guides will prevent this and will only cost a few hundred. At this point, the valve covers need to be removed, the cam timing checked and the guides checked for wear. Also, check the color of the guides. If they are white or lite tan than they have already Been done. If they are dark brown than replace them before the engine is started again. There has been a lot of old 126's junked because the plastic guide broke.

Paul

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84 500 SEL (307,xxx miles)

Tell 'em how much it costs to do an MB V8 timing chain at Bay Area shop rates + parts. You don't want anyone other than an MB surgeon on that job. I shudder to think.

But if you love your car like your sig says you do, probably better do it now and sleep at night.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

Actually synthetic oil, although it is great for everything else, unless changed as frequently as changing dino oil, might WORSEN timing chain wear rate. It is tiny particulate that wears the timing chain, or "stretches" it as it is called. The only reason that the synth might WORSEN wear rate is because you would tend not to change it as often.

Frequent oil changes are the best way to keep particulate at bay. These are particles too small to be captured by the oil filter. Read my sig.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

real Men use timing gears.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

You CAN do the chain yourself - I have. The most important warning above, however, is the one on the guides. You need to have those checked out.

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Henry Bofinger
1989 560 SEL (black/black)
2001 Audi TT Roadster (silver/grey)

100k is the recommended milege.
It's quite easy to tell if its ever been changed. Remove one of the valve (cam) covers rotate the engine and look for a master link on the chain. A replacement chain will have one, the factory one won't. It's not the chain you need to worry about the most. It's the upper chain guides. They fail at about 100k. The chain jumps off the cam sprockets and usually blows out one of the cam covers. Since these are zero clearance engines the valves and pistons collide and thats really bad ju ju. There are two lower guides that never seem to fail. (They say) When I did mine (being an anal retentive motor head) I replaced the cam sprockets, crank sprocket, and lower guides. I found one lower guide just as worn as the top ones. Chains and sprockets should always be replaced as a set. They wear into each other.
MTCW. Good luck.

How do you know? you take off valve cover, rotate engine untill cam tming marks like up on there marks then read crankshaft marks , usually your going to find one mark a little off, but i change them at 4-6 degrees off, 2-3 its not going to matter but ive seen them as high as 8-9 degrees off reading at the crankshaft, dont wait above 120,000,do as everybody advises inspect now for source of the rattle, ive removed drivers valve cover when there was no complaint and to my horror found the plastic guide already broken and dropped but didnt catch the chain to do damage, you can attach new chain to old and rotate after installing if you want to just install chain and upper guides, you can but thats another subject.