I have a 91 Mercedes 560 SEL with 130K. Recently the car developed ticking noise that sounded like the timing chain was slapping on the chain guides. The noise occurs all the time when the car is in drive (D). I can hear the noise when I am driving at slow speed with the windows down. The noise is coming from the driver side of the engine just under the valve cover. There is no noise when the car is in P or N. I took the car to reputable garage where they changed the timing chain, the upper chain guides (a total of 4), and the timing chain tensioner. All of that didn't help at all; the noise is still there. I have been told that the cams looked to be in excellent condition and the noise might be coming from one of the rocker arms or hydraulic ball stud assembly. I was wondering if such symptoms occurs due to faulty lifter or rocker arms? Is it going to damage the cams if I continue driving the car ? and is there a way to check and be sure before changing the rocker arms or lifters. Any help will be greatly appreciated.


Thanks