[Richard in South Carolina]

2012SLK 350 – Mostly in the cold of the winter but any time after the car sits forover a week to ten days, when I start the engine I hear what in the old days Iwould call a sticking lifter or valve. Tap, tap, tap. It usually lastabout 10 to 45 seconds and does not do it when the engine is warm. I live a significant distance from the dealerso they have never heard the noise. Itis embarrassing if friends happened tobe with me and keeps me awake at night wondering if this is a serious issue. My warranty is up soon so I am wondering ifthis is cause to consider purchasing the extended warranty to protect myself. Doesanyone have thoughts about what this noise is all about? :frown:

 

[Hal Adams]

Hydraulic lifters drained, timing chain tensioner drained and/or non return valve oil pump.

 

[slk-smile]

I had a new Rover Turbo (famous 'K' series engine) many years ago with exactly same problem. It was the hydraulic lifters on the valves waiting for system oil pressure to normalise. My SLK doesn't do it as far as I know... but again, my roof is always up when I start from cold and it would have to be a really loud sound to become noticeable inside the car.


I 'fixed' the Rover by using Castrol Magnatec engine oil. Seems their claim of magnetic oil really had some substance.

Meanwhile, the R172 SLK 350 is a super noisy ticker tocker at idle in any event - hot or cold.

 

[Alex 3]

What weight of oil are you using? 0-40W?
It sounds like an oil pressure build up issue to me too.
If it persists, distance or no distance I would get it to a dealer. An engine failure is a huge deal.

 

[Richard in South Carolina]

What weight of oil are you using? 0-40W?
It sounds like an oil pressure build up issue to me too.
If it persists, distance or no distance I would get it to a dealer. An engine failure is a huge deal.

I don't know the weight of the oil. The Mercedes dealer receipt says 8 OIL4 Mobilsynthetic

 

[Alex 3]

Every invoice I ever received from the 4 dealers I have used over the last 28 yr will say something like:

8 0W40S Oil on it.

Look again.

 

[Richard in South Carolina]

Every invoice I ever received from the 4 dealers I have used over the last 28 yr will say something like:

8 0W40S Oil on it.

Look again.

My invoice says 8 OIL4 Mobilsynthetic


I called my dealer and he said it is 040 or 540 Mobile 1 Synthetic

 

[DSSG]

Turn up the radio or wear ear muffs!