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I have an issue with noises from the engine bay, whining noise mostly. I've checked all the pulleys and the ABC / steering pump and there's nothing there really standing out. I did already replace the pulsation damper on the ABC system as that was recommended. That does not seem to have made any difference.
So my attention has swung towards other possibilities.
I noticed the crankshaft pulley is moving a lot. Pushing it with a lever and it seems solid enough... but it still looks wrong when the engine is running. I've compared it with my BMW which is perfectly steady.
Before I change the crank pulley I'd be interested to know if any other owners can see their crank pulley and whether or not they all have a similar vibration. I'm doubting a lot that it is the cause of the noise but I still want to fix it if it's inconsistent with the way things are meant to be.
After looking at it more I just think it's not right at all and decided to buy a replacement. It seems to be a common failure on Mercedes engines of the era and the parts are cheap and readily available. Cheap and readily available parts is always an indicator to me that it's a known issue. Same as if the dealer carries the part in stock... it means they change a lot of them!
It's definitely not an engine bearings issue. Firstly for the reason that the noise coming from the engine would be enormous, huge knocking and banging noises if the bearings were worn out like that. The engine would have a hundred miles left before complete destruction! If you can see the video you'll notice the middle of the pulley is pretty smooth. The harmonic balancer (which is the rubber sandwich between the inner and outer parts of the pulley) is failing. The outside of the pulley is wobbling but the inside is smooth.
I'll do the pulley as it 100% requires replacing. Then we'll see how it is after that.
That seems fine indeed. Changing the balancer is going to be a job because the space is quite limited
Naa, it'll be easy. The engine bay has room for the v12 so with mine being just the little v8 I shouldn't have any trouble getting down there to switch it over. Can always take the radiator fan out for another few inches of clearance but I may get away without.
The only snag I've seen watching the videos of other people doing it is that you're supposed to use a special tool to brace the pulley before attempting to remove the nut. I'm not sure why this is recommended as I can't really imagine the engine and gearbox not being strong enough to withstand someone removing the crankshaft pulley bolt. So whilst I'm not especially worried about removing the nut without a brace I probably will try and rig something up to hold it.... this will add some time to the job.
Naa, it'll be easy. The engine bay has room for the v12 so with mine being just the little v8 I shouldn't have any trouble getting down there to switch it over.
Nice! I'm so used to the non existing space before the V12 that I tend to assume the V8 has this problem too
Originally Posted by ejenner
The only snag I've seen watching the videos of other people doing it is that you're supposed to use a special tool to brace the pulley before attempting to remove the nut. I'm not sure why this is recommended as I can't really imagine the engine and gearbox not being strong enough to withstand someone removing the crankshaft pulley bolt. So whilst I'm not especially worried about removing the nut without a brace I probably will try and rig something up to hold it.... this will add some time to the job.
Because you'll rotate the engine and the engine should not be rotated in the wrong direction, which you are doing when you are removing the balancer's nut.
I wouldn't really of thought rotating the engine backwards was much an issue really. I think if you were spinning it in reverse at 500rpm for a prolonged period you would cause damage but if you're just opening a nut and end up turning it 10-degrees in the wrong direction in the process I really don't think that'd be an issue.
Did the job today. I already had a 'special tool' for another car in the workshop so I adapted it a bit by putting some studding through the holes with a nut on either side to hold it steady.
You can see it's a nice shape for fitting into the front of the crank pulley. I don't know what the original purpose of this tool was but it's great for this job. I don't use it for anything else so doesn't matter that it bends a bit in further photos.
The reason you have to use this tool is that the engine does not lock when the car is parked like I thought it would, I don't know why I thought that, really silly. I suppose 'park' only locks the gearbox because the engine has to be able to rotate in that position so it can be started. Seems obvious now!
I couldn't get a good grip for removing the nut so moved it to sit across the pulley and that chipped and cracked it. Didn't matter as I knew I had the right part to swap on after.
The 'special tool' is just the right length to rest on the front chassis member and that provided perfect support for loosening the crank pulley nut.
The tool bent during removal but if anything that seemed to make it fit even better and when tightening the pulley I rested it under the chassis member.
The information I read elsewhere was to tighten to 200nm and then 1/4 turn. Job done.
Made no difference to the noise but it did obviously rectify the vibrating outer section of the pulley. If you lose your accessory drive due to separating harmonic balancer that is a show stopper. You'll be by the side of the road waiting for a truck. I've got a 600 mile trip next week so good to get it done.
I gave it a quick run when the belt was off just to check my noise is nothing more serious and it was silent. So definitely coming from one of the accessories and most likely the ABC pump.
Has the ABC pump ran dry before? How is your hydraulic oil level?
Just a word of warning, if your hydraulic oil level is too low and the ABC pump has indeed ran dry, metal shards are in the system and things will go wrong.
In that case, please do yourself a favor and find another car to do the 600 mile trip.
Plenty of oil in both reservoirs. I think I'm going to buy a second-hand pump and swap it in. See if there's any change. Then I can get the original pump refurbished.
09-05-2022, 11:51 AM
