Hello, I own a 560 SEL and I have a knock from the top end of the motor. Is the car safe to run ? What are all the possible causes for this because I would like to know if it is a job I can handle. I just had an oil change two days before I started hearing the knock.

You are most likely hearing a timing chain that is about to be a 5,000 dollar problem if you drive. If you get it fixed now, it could be a 1,000 problem. If the timing chain and rails are bad, have the whole set done. (chain sprockets, rails, tensioner and all factory parts!!!)

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

The chain was checked by the dealer only a few weeks ago so I am wondering could it be a lifter problem ?

My 85 500SL has a mild knock that sounds like it's coming from the valve closest to the driver. It's not very loud but of course I am concerned. I saw a post about damage to a cam if there is a rocker problem, but if a valve compensator is worn (cupped) or something, is this a problem to drive? Please advise and thanks for the great site.

Steve

85 500SL Euro

I have seen many rockers and cams worn, but I would call this a tapping noise, not a knock.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Yep, it's a tap, not a knock. I just had a timing chain replaced and the cams are fine. Rockers okay but replaced as well. Still tapping and the shop said it's a lifter and when I get a chance, I'll leave it with him to find out which one and replace it. Anyone know how to determine which one is bad?

Steve
85 SL500

Depending on the miles your car has,,,,,if the noise is a lifter, you would probably be better off replacing all of them at once.

They all have been in there for the same miles and if one is failing, others may soon follow. If you do them all at once, you can forget about them. If you do just the one or two that are bad now, you will always be wondering,,,,,when the next ones will start to tick.

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My 500SEL was making loud tapping noises. It turned out to be two loose lifters. After the lifters were retorqued, all noises disappeared. The tapping started after I have switched to Mobil 1. I wonder if the lower viscosity somehow loosened the bolts.

[This message has been edited by TommyMB (edited 06-16-2000).]

Boy, that Mobil 1. That is some kick ass oil. I wonder if I can get it to change my plugs...

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Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325