Ticking form a rocking engine? Engine shock? Rubbing?
 

I have some noisy lifters and am getting ready to change and shim them but during inspection I noticed that if I give it throttle, the engine rocks and it gives off a ticking sound that doesn’t sound exactly like a ticking lifter. When I drive I hear the sound too, only under load. If I gas it, it ticks, when I back off, it stops. What could cause this? Is there anything that could rub? It sounds like it’s coming from under the engine. I changed to summer oil and the noise started. This has got to be a tough one without being able to examine the car.

Bad motor mount and causing a manifold leak. The tick is the manifold leaking when the motor torques. Fix the mount and see if the motor stays quiet. If not change the gaskets of the leak is there.
My.02

I changed the motor mounts and sub frame mounts last year. I did not change the Trans mount or engine shock. Could these be causing the problem? Manifold leak sounds possible. Could I tell with a stethoscope or something?

Thanks Ken, You were right about the Manifold, but...
 

The good news first: The noise is from a loose manifold. I tightened it up and the noise is gone! The bad news is that the nut was spinning under load and will not take the 75 nm it is supposed to take. It is holding about 25 nm and is sure to pull out again soon. I can tell this is going to be a lot of fun. It is the #4 upper stud. I don’t think it can be drilled and an insert installed without taking off the manifold and either pulling the head or the motor. Not only that but I bet others pull out when I remove the manifolds. That will be another thread.
This is just great. Why do some cars have no problems and I have so many?

a turned stud
 

seems like an unusual problem for a benz. so i would not assume that any others are bad. this one was probably caused by inept mechanical work.

you are right though changing it will be a pita.

tom w

can you use 2 nuts on it, the first nut may spin, but if there is enough good thread, perhaps a 2nd nut can be used to tighten the stud. I used this on pretty eroded manifold studs and it worked for me.