C180K Knocks at startup some times

[daveuj]

Hi As a new member to MB club forums I will be greatfull for any help.
The problem I have is my c180K sport coup'e has a knock at startup this will only happen 1 or 2 times a week and the car has only done 23.000 miles,it has done this for some time and my MB Dealer says no prob's should be ok after next service (2.600)miles.
Sounds like the filter is filling with oil after oil change or stuck tappet?
Any Help would be great.
Thanks

 

[st13phil]

Does the knock disappear pretty soon after startup, i.e. in the first few seconds, or does it go on longer? Also, is it a light or heavy knock?

If it stops after a few seconds and is light then it could be an hydraulic lifter that has a leaky check valve, so nothing really significant to worry about. If it goes on until the motor's warm and/or it's a heavier knock then I'd get another opinion.

 

[television]

As st13phil there is a big difference between a knock and a tapping noise, open the bonnet before you start the car and listen to see if the noise is from the front of the engine or the top

 

[daveuj]

Hi all I know this an old post but still very ramdon think it is the oil getting round engine do you think an engine flush would help?
Thanks Dave

 

[jaymanek]

yes change the oil, go for a good oil such as Mobil 1 or Magnatec and see how that affects it.

 

[recycled]

Mine started soon after fast idle.
itwas a cracked exhaust manifold expanding. it got sorted

 

[Jesse]

If your car only has 23K on the odometer it shouldn't be making any abnormal noises. Lifters are the most common area to look at for a tapping noise. However a timing chain tensioner will give the exact symptom; the noise will go away after a couple of seconds. What oil are you using? Even a good synthetic needs the filter changed every 3K miles. The oils have no problem lasting 10-15K miles, the filters restrict too much oil when they are clogged. Personally I can't stand Mobil 1, you either love it or hate it. AMS oil is a fantastic oil.

 

[daveuj]

Hi Jesse did not think you had to change the filters so often? but may put the uprated long life filter in and give it a go.
sounds very much like the timing chain tensioner.
had a service at MB not so bad now.
Had Mobil 1 in love it but MB put in castrol.
Thanks Dave
Hope the weather is ok in Florida?bit wet of late in the UK.