I did a bunch of maintenance work on my e55 but the only ones where I touched the engine would be valve covers, breather covers, and engine mounts. I finished it all up and took the car for a test drive. It had some codes pop up and idled high but I figured all that out. It was a hidden vacuum line that gets popped out when you take the valve covers off.



https://mbworld.org/forums/w211-amg/883677-valve-cover-gaskets-change-now-throwing-p0507-p0455-p0505.html



(here’s the forum I posted and also how I figured out the issue)



Now when I plugged that line back in and started it up the codes were gonna and the engine idled normal and sounded normal too. I took it for a test drive and it was good. When I came to a stop sign I thought I heard knocking but wasn’t too sure. I pulled the car into my garage and let it idle. I got out the car and could hear a knocking 😥. I thought my mind was playing tricks on me because there was no way my engine was knocking. It wasn’t a quiet knock either. I shut the car off and checked the oil level through the dash. It was at 6.5 quarts. But it has always been at this level, even other e55 owners had that same reading and no issues. I added about 1.5 quarts and started it up again but it was still the same noise. I have Mobil1 5w-40 in there right now but I have Liquomoly 5w-40 which was ready to go in today for an oil change. Until this happened 😕. I have a lot of mods planned for this car but it’ll be a while before it happens if this motor needs a rebuild. I’ll attach a video of the knocking below and let me know if something doesn’t make sense my writing isn’t the best.





This is when I first recorded the tapping it was sort of slower






This is the second time i recorded it and after I tried revving it to see if it gets louder






I had someone revving it so I could see if it gets louder

 

remove both belts and try again

 

Yes, could be the pulley bearing on the super charger

 

That is also my best guess for now

 

So I removed the supercharger belt last night right after I posted this and the noise decreased by a lot but the supercharger was still spinning because it was still getting air. The knocking was there but much less. How can I confirm it’s 100% my bearing and not something knocking within the engine. I recorded a video of it running without the belt and also me free spinning the pulley while the engine was off and I was getting the same sound (I think) I would be pretty happy if it is just the bearing and nothing more major.



video of car running without supercharger belt :



video of me spinning the supercharger :


thanks for the help everyone

 

How old is the bearing? My advice: just replace it for about $50 for peace of mind

 

I’m not sure I bought the car with it and never asked about the bearing history. Is there a chance the sound is from the bearing. Because it’s a big coincidence for the bearing to go bad as soon as I do all that maintenance.

 

Nope. Mine went out only a few hundred miles after I spent three weeks and almost $2000 for parts on a major preventative maintenance at 150K miles. I should have just replaced the damn bearing while I had the car apart. When it fails, it fails.
If the problem is the rear internal bearings, that's an entirely different and more serious issue. Fixable but far more effort.

 

Same goes for the crank pulley, when it fails it fails. Or the plastic pulleys like the infamous double pulley. Or the supercharger pulley etc etc

Preventative maintenance is the name of the game

 

Just get a rag or where a glove and stop the supercharger from spinning with the belt off. It does not take much to stop it and then you will know for sure.

 

That back and forth noise of the 2nd video is just bearing lash and is normal. You can't turn the inside of the supercharger by hand because it's a clutched pulley. It turns any time the engine is running because that's the only way air can get into the motor so the engines vacuum forces the supercharger screws to turn, and you can't stop them by stopping the pulley, again because it's a clutched pulley. At idle the ecu is programmed to release the supercharger clutch. I think the next step is to pop off the supercharger pulley to remove the clutch and spin the supercharger by hand in one direction to see if you hear any noise at all.

Someone correct me if I'm wrong, please.

 

You can turn the supercharger by hand from the magnet housing.
You can stop it from turning while running on a clutched set up by just putting pressure on the magnet drum and it will come to a stop and do this with the belt off.
If noise instantly goes away, you know its the supercharger and that's an easy fix as well if it is the rear bearings.

 

could I take the supercharger pulley off and turn the car on? I’m assuming if the bearing is bad I could take the whole pulley off then try starting it and if the noise is gone then I’ll know it’s the pulley bearing for sure right? I’m just not sure if it’s ok to do that or I’ll ruin something. Thanks again

 

Yes you can, while stationary the bypass valve will be open, so no pressure is being build.



In a load sitaution:



[edit]
Seems I cannot link the pictures anymore...

 

I am not going to speak for my self but If you are going to listen to anybody here ,listen to Nd-photo at least. You are NOT going to ruin anything. This is a very very simple diagnosis.

 

I'm not all knowing, but I know by doing haha. Also dont forget yourself, @bbirdwell , @UncleBenz55 and many other knowledgeable people on this awesome forum.

 

sorry I’m a little slow you gotta give it to me straight. So this is a good way of diagnosing wether it’s the pulley bearing or the rear bearings correct?

 

Both..... turn the pulley by hand and see how it sounds/feels. Then turn the supercharger and see how it sounds/feels.

 

sorry I forgot to add to the forum that I started the car up without the supercharger belt and stopped the supercharger from spinning by doing exactly what you told me and the noise did go away. Now I want to figure out if it’s the pulley bearing or the bearings inside the supercharger. Could I completely take off the pulley so I could rule out the pulley bearing or that’s not how it works.

 

Did you turn the pulley by hand like I said to see how it feels/sounds ?
Did you turn the supercharger by hand to see how it feels/sounds ?

 

If you go up a little I posted a video of me turning the supercharger. How do I tell wether I’m turning the pulley or supercharger I thought they both spin together?

 

OK so if that is not making noise,the pulley you are turning, then it's the rear bearings assuming you turned the supercharger "large black drum behind the pulley" and it made noise. Just guessing because this seems to be very difficult to reach a conclusion so I would say rear case bearings.

 

I really appreciate your replies man and to everyone that replied aswell. I went out there just now and turned the black drum only and it was making noise but the pulley spinning alone wasn’t making noise. Here’s a video I took



what would be my next steps from here as in changing the rear case bearings or diagnosing if it’s another issue.

 

OK last shot...with the car running while it is making noise with the belt off, stop the supercharger drum from turning and the noise should go away. Don't worry it is just coasting along and doing nothing so you are not going to break anything. Also try and have the camera running so we can see.

 

OK I want to confirm before I go out and do this. I’m going to put the supercharger belt back on and turn the car on. With the supercharger pulley still spinning I’m going to stop the black drum from spinning. Correct? The pulley will still be spinning but the supercharger won’t be and if the noise goes away then it’s definitely in the supercharger.