Replaced engine mounts & shocks but engine vibrates louder. What cause(s)?
 

I recently replaced my two engine mounts and two engine shocks on my 1984 300TD. After I replaced them, I expected less noise and vibration but what I got was a slightly loud noise like metal vibration coming from the engine well somewhere. I'm suspecting that I also need to change the transmission mount, but after a visual inspection it looks fine and I have decided not to change it.

Does anyone have any ideas why I would get a slightly louder vibration sound coming from the engine well after I changed my engine mounts and engine shocks? Thanks.

When was the last time the valves were adjusted and timing chain checked/replaced?

You might also check the position of the rack dampener bolt and if there are any threads left, try turning it in a slight bit to see if the shake goes away.

Grab the air cleaner housing and shake it around. If this duplicates the sound, you might need a new support bracket and rubber support bushings.

Also, my opinion is that you should always replace "wear" components in a complete set. As in, pads for both front brakes at one time, ball joints upper and lower on both sides at one time, etc. What I am saying is that you should go ahead and replace the rubber mount block at the back of the transmission. This is generally considered part of the "engine mount" system.

Ken300D

The air filter housing can make a helluva racket. The AFH stands so close to the throttle linkage and cam cover that one loose or damaged AFH mount can produce a serious percussion section. Now that the shocks and mounts are replaced, vibrations are going to travel through the engine and bay in different fashion than before.

Thanks for all your suggestions.

Slowmoe, the valves were last adjusted 3 months ago and at that same time, the timing chain was checked and my mechanic said that there's no stretch.

Also, my air filter housing mount is fine. I check this often as I know from comments here that a broken air filter mount is often the source of vibrations and noise. On a side note, if any of you guys purchased yours from a MBZ independent shop, and it broke on you, don't go out and buy a new one; they should replace a new air filter mount for free as it will be under warranty. Not sure how long it's good for, but mine broke 9 months after I purchased it and my mechanic gave me a new one.

Back to the new noise problem. The new noise was not there prior to changing the engine mounts and engine shocks but is there now. So, I kinda agree with Ken's advice to go ahead and change the transmission mount as I believe that the engine is raised slightly higher now because of putting in the engine mounts and the transmission is a bit lower. I think the engine & transmission is out of alignment and that is creating the new noise I am hearing. This is just my thoughts, I could be wrong.

Aaron, I'll also replace the rack dampener bolt, a good idea, since the last time I replace it was about 1.5 years ago.

Regards,

:)