This just started recently. The air filter housing and turbo stuff below are vibrating, and I mean really VIBRATING. And it's steady and constant. Kind of like:
mmmmmmmmmMMMMMMMMMMmmmmmmmmMMMMMMMMMMMmmmmmmmmMMMMMMMMMM

That's the best I can do to describe it. It is that constant pattern, with the MMMMMM's being when it vibrates. Any idea what's going on here?

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1983 MB 300SD Turbo Diesel

Broken air cleaner support. Common problem.

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Never a dull moment at Berry Hill Farm.

I changed one mount the other day, and the bracket didn't look like it was broken. The mount I changed was the one closest to the side of the car that screws up into the air filter housing. The nut that screws onto the mount inside the housing works itself almost off within ten minutes of vibrating at idle.

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1983 MB 300SD Turbo Diesel

How old/good are your motor mounts?

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

The motor mounts are on the list of things to do. I thought that they may have something to do with this, but the constant rythm of the vibrating is new. You can almost keep time with the interval that it vibrates.

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1983 MB 300SD Turbo Diesel

IMHO, It could be a fuel filter issue.

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http://i136.photobucket.com/albums/q.../ForumSIg2.jpg

I was also thinking it was something beyond a mount issue. It could be the filters. I'm changing both filters tomorrow, but I put them on in December, so they should be fine. The reason I don't really think it's the air filter mounts is because it's a steady interval of vibrating vs. not vibrating and it's not just the air filter housing. It's the turbo exhaust (?) under the air filter as well. It looks more like that is vibrating and causing the air filter to vibrate with it.

It's sounds like my car is out of breath and it's heaving for air, and every time it exhales, the turbo and air filter vibrate big time. Even if the air filter mounts were perfect, it would still be vibrating like this, it just wouldn't be as loud. What else could it be?

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1983 MB 300SD Turbo Diesel

Does the vibration go away when you increase the RPM's? Sounds to me that it is coming from your air cleaner. You could try to dampen the sound by placing a piece of radiator hose between the valve cover and air cleaner.

Also, I would check the heat shield that is covering the exhaust rear of the turbo near the battery.

But if your engine is running rough, then you have the issue of figuring what is the cause.

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1983 123.133 California
- GreaseCar Veg System

What are the RPM's at idle?

It does go away when I give it some throttle. Unfortunately I can't tell you what my RPM is at idle because my tach doesn't work. I could dampen the sound, but it will still be vibrating.

Although I can tell you the RPM, it does seem like an idle thing. It's sounds like the RPMs drop while idling, and that's when it vibrates.

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1983 MB 300SD Turbo Diesel

If you know it is your engine vibrating and it is not any body pieces (i.e. heat shields) causing it. Then you should start looking into doing the following:

-motor mounts and engine shocks
-try diesel purge first, then have injectors balanced and test for spray patterns
-check for air leaks in the fuel system from the tank on forward
-adjust valves
-check injection pump timing
-check for timing chain stretch
-check cylinder compression

BTW - How many miles does it have?

Also, tach get your tach working. It maybe a simple fix as to replacing your tach amplifier.

Good luck

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1983 123.133 California
- GreaseCar Veg System

All these engines have a resonance that will affect rattles here and there, it's the change that you're asking about. rmarzan has a good point, except for balanced injectors, not sure what that is. I had a set checked at an authorized Bosch shop, they told me the spray pattern is good as well as the pressure, unsure of anything else that would affect. Purge can't hurt, not sure it helps, have done on all five MBZ. IP would be one of the last things to do, sounds difficult. Tach is usually the amp, a bit pricey, (have replaced two, problem solved) but there you go.

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83 SD

84 CD

The only reason I ask, is that if you have your idle set to high you can get excessive engine shaking and also if the idle is to low. At least that is what I experienced. While I was making the adjustments (that I note from a previous link below) I noticed a very wide range of engine shake and air cleaner vibration at various idle settings. Idle to high = engine shake. Idle to low = air cleaner vibration and I mean vibration!
When I had the idle and rack damper adjusted correctly I noticed a huge difference. I agree with others in this forum in regard to the other area's to check. I would just check the idle and rack damper first, as it does not cost anything but your time. If the efforts make no difference...just return to original idle setting and check the other items below...Good luck

1) Fuel filters
2) Diesel purge
3) check engine shocks, mounts, and tranny mounts.
4) Injectors if necessary.

Today, I made an effort to fix the excessive shake at idle. I adjusted the Rack damper with a full clockwise turn. It did not make a visible difference. However, I took the old girl for a spin and the excessive shake was a little better...but not quite fixed. I reduced the idle from around 800-850 to 725-750. The excessive shake appears to be gone. I took the old girl for another spin after the adjustment and see no signs of excessive shake. Also, power is still very good and she still starts right up. I guess I should drive it for about a week or so before I claim victory. But for now the shake is gone...

Quote:

Originally Posted by JimZ It does go away when I give it some throttle. Unfortunately I can't tell you what my RPM is at idle because my tach doesn't work. I could dampen the sound, but it will still be vibrating.

Good Point, I forgotten about the Rack Dampener screw. An updated screw (gold type) could also do wonders.


What meant by balancing the injectors is to make sure they pop close to one another - around 135 bar.

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1983 123.133 California
- GreaseCar Veg System