Knocking (tapping) sound from engine
Thread Starter
Senior Member
Joined: Jun 2010
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Mercedes E55 AMG (2006), Mercedes 560 SEL (1991)
Knocking (tapping) sound from engine
Hi Guys,
I inherited a 92 model 560 SEL (ECE engine) which had been parked for about seven yrs. It's only done about 17k miles and I understand it was running faultlessly when it was parked. I serviced it (including the injector system) and it started up without too much trouble. It does however seem to idle on 7 cyl with the 8th firing only from circa 2500 rpm at which point it flies. There's also a knocking (tapping?) sound from the engine at low revs.
Does anyone have any ideas what this could be? Injectors, valves, or something worse? Much obliged for any assistance.
I inherited a 92 model 560 SEL (ECE engine) which had been parked for about seven yrs. It's only done about 17k miles and I understand it was running faultlessly when it was parked. I serviced it (including the injector system) and it started up without too much trouble. It does however seem to idle on 7 cyl with the 8th firing only from circa 2500 rpm at which point it flies. There's also a knocking (tapping?) sound from the engine at low revs.
Does anyone have any ideas what this could be? Injectors, valves, or something worse? Much obliged for any assistance.
Senior Member
Joined: Jun 2006
Posts: 303
Likes: 1
From: Northern California
It changes all the time
First of all we need to know what car you have, because the last 126 chassis 560SEL was produced in 91. The 140 chassis was introduced in 92. What is your chassis #?
Thread Starter
Senior Member
Joined: Jun 2010
Posts: 267
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Mercedes E55 AMG (2006), Mercedes 560 SEL (1991)
Sorry, error's mine. It is a 1991 model. Original owner had choice between final w126 and then new w140, and bought both - a 560sel and a 600. Not in town at the moment so cannot send the VIN No but a previous check on the MB Russa site confirmed it was a 1991 560sel and had the ECE engine. Will send VIN when I get home tmrw.
Thanks for helping.
Brgds
Thanks for helping.
Brgds
Senior Member
Joined: Jun 2006
Posts: 303
Likes: 1
From: Northern California
It changes all the time
I don't need the VIN. By the way you can drop the the number, because it is redundant. VIN stands for Vehicle Identification Number. So if you say VIN number, you are saying vehicle identification number number. Same thing applies to ATM machine.
That being said, I think you have a failed valve lifter. You just need to listen with a stethascope and determine which one. As an interesting point everyone says that the tapping noise is a failed lifter. Even though the lifter is at fault, it doesn't make any noise. The noise you hear is the valve slamming shut without being quietly being closed by the lifter.
That being said, I think you have a failed valve lifter. You just need to listen with a stethascope and determine which one. As an interesting point everyone says that the tapping noise is a failed lifter. Even though the lifter is at fault, it doesn't make any noise. The noise you hear is the valve slamming shut without being quietly being closed by the lifter.
