Yes, I'm in Jacksonville, FL. I'll pm you. Mark

The flex plate (not disc) looks like it is a likely culprit. Hookedon210s explained where it is and how to get to it, along with other interesting stuff about mercs on the phone to me (Thanks!).

I've got the car jacked up and the bolts visible on what looks like a flywheel between the engine rear crankshaft exit and the torque converter. But I don't know two things:

`1. what torque should the bolts be at for the flex plate (they're only a 13mm so I'm thinking they don't have to have too much torque, but it seems getting the torque right would be a good idea!) I looked in the service manuals, but didn't know where it would be and gave up. Seems they don't have flex plate in the manuals. Anyway, when tightening the bolts I could get to, the crankshaft turns with them, so it is hard to get a good grip and torque on them. Should the car be in park or neutral, or drive?

2. how to turn the engine over so the next set of bolts are visible. Hookedon210s told me but I think I misunderstood. How do I turn that thing over while I'm under the car? or is there an easier way? I tried turning the vacuum pump bolt clockwise but it just slips.

thanks.

The torque for those bolts is 42 NM (or 31 ft-lbs according to my conversion table). On gas engines (I assume this will also apply to diesel engines although they have twice the compression) you can turn the engine in small increments by using a large headed flat head screwdriver as follows:
1. With the screwdriver shaft against the driver's side of the opening in the bottom of the bell housing, apply the screwdriver blade (parallell to the direction of travel) to the torque converter.
2. With pressure applied to the torque converter, lever the screwdriver towards the driver's side of the car to move the torque converter an inch or so clockwise as viewed from the front of the engine.
3. Repeat until next set of bolt heads appear in inspection window.

Once you have successfully moved the torque converter a few times you will get the hang of the correct positioning of the screwdriver. Also, you can always bump the engine ahead with the starter or a socket applied to the front crankshaft pulley and use this method for final alignment. Mark

Thanks, I did that. However, I used a socket on the crankshaft to hold the crank still so I could torque the flex plate bolts. They all were at or above torque. I loosened a few and retightened them.

but the vibrations are still the same.

I noticed that when I took the tranny mount out to check it, the car didn't vibrate as badly even though it had the same tranny mount back in it. This makes me think it is something to do with that area. Something may have shifted when I took the bolts out of the tranny mount support brace and didn't have anything under the tranny to support it (could I have damaged something there?)

ANyway, I am getting to think this is a mystery never to be solved.... Or maybe it is my injectors? They're pretty loud and nailing - maybe they get some funky harmonic vibration going at high revs, I don't know, I 'm reaching here!

Back to engine mounts?

Probably becuase I just returned the mounts I bought last week to the store yesterday....

How do you tell if the mounts are OK or not? Is there a wobble meter I should invest in?

Hookedon210s has been helping me a lot with this. He had a look at the car (we live in the same city) and told me the mounts are shot. They were. I took them out and they were pancakes. I replaced them with mounts from the 300D - Hookedon210s said these are better becuase they're harder. Also, he said it is worth the money to get good mounts, ie mercedes mounts, not OEM. I replaced the shock absorber which hides under the one mount on the driver side.

Anyway, the car drives a lot differently. The engine definately feels smoother and quieter. However, that infernal whumping is still there! It is sort of smoother now, but it is still noticeable at 60mph. It is a cyclic vibration that feels like it is coming from the engine or tranny. It increases in frequency when I hit the gas. At 65 it dissapears slowly. I've tightened the flex plate, replaced the motor mounts, checked the tranny mount - what could it be! Maybe it is the tranny mount - it was shorter byabout 1/4 " than a new one. I didn't think that would make a difference, but maybe it would.

Any ideas?

Motor mount install tips.
For those of you attempting this the first time, save yourself a few hours of swearing and frustration - there is one allen key bolt in the mount on the driver side that is hard to get to. It is the one that is nearest the engine and under the protective plate that goes over the mount. The way to get to this best is to

1. support the engine under the oil tray (use a piece of wood and lift jack)
2. release the main 8mm allen bolt that holds the engine onto the mount (do this from under the car), then
3. lift the engine carefully using the jack. Be sure you have released the engine stop between the engine and tranny so the engine can raise up. ALso loosen the fan shroud so the fan doesnt' hit it.
4. the engine should lift high enough to allow you to get to the allen bolt holding the mount to the frame from on top. You will probably have to loosen the 8mm bolt on the other side engine mount quite a bit first - I did.

BTW, recommended tools - 6mm and 8mm allen wrench sockets so you can use a air rachet or click type wrench.

I changed IPs a couple months ago, and this thread got hung up with 176 other emails at the old IP. If you still have the problem, it might be the anti hop kit that is bolte between the cross member and oil pan. You can loosen the bolt and let the engine settle to the new position.

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AutoZen, yes, I still have the problem. Thanks for replying.

By anti hop kit, do you mean the engine stop -= the kinda L shaped mount thing that stops the engine from lifting too much? My car didn't have one of those, but I installed one, but the whumping continues....

That's the one. Loosen the bolt and move the engine around to see if it resets in a different position.

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