That's good info! hope I remember next time I'm in there.

hi, there seem to be 2 versions of Liqui Moly 0w-40, can you tell me which one of these you found quietened the pump? Ive already tried mobil 0w-40, Liqui Moly 5w-40 and a cheaper 5w-40 id say they were all quite similar noisewise with Mobil 1 possibly a little quieter, but still noisy. It drives me mad especially as my dad has an identical car with double the miles and his one is really quiet.

LEICHTLAUF ENERGY 0W-40 Cant find this available in the UK

SYNTHOIL ENERGY 0W-40 this one is readily available but only covers the MB229.3 spec but not the MB229.5.

ive been experimenting with different oils since i bought the car 2 years ago,

None of those oils.

Looks like the oil pump scavenging gear noise is being addressed with lobe type gears. .

It's an interesting concept, but the execution would be very difficult to get right, and it's a quite big job. Would have preferred to see him find a way to key the two shafts to make sure the alignment is perfect without guesswork.

I actually just did most of the job to swap out the o-ring out today. Couldn't quite finish up to see if it had any effect on the more pronounced noise mine has been making lately, but the O-ring was definitely hard and brittle. It makes a clank noise when you drop it on a metal table for instance. The difference in seal quality between old and new o-rings was night and day as well. With the old one, the pipe just falls right out. There was virtually nothing holding the two pieces together, not even suction. With the new O-ring, it's actually quite difficult to even put the pipe into the hole and once in it stays in place, the seal is that tight.

Seeing it in person makes me realize how poor the design really is as well. There is nothing really holding tension on that joint. The O-ring is only being pressured in the radial dimension by the smaller pipe it fits over, and the larger bore it fits into. There is nothing to apply force inward and crush the washer between the raised section of the pipe and the body of the pump, which would help maintain a seal even if the rubber hardened in my opinion. It's just held into position by the brackets that attach the pipe to the bottom of the engine block, and they are not positioned precisely enough to apply the proper forces on this joint. This can be clearly seen in the shape of the old washer, which was squared off on the inner and outer edges of the circle where it was squeezed in the bore, but budged out round to the sides because the pipe is not held in the socket with any tension at all. If it was under pressure from all sides, it would be squared off on all 4 sides rather than just 2.

I will be finishing up on mine on Friday as the shop is closed tomorrow. Will report back if I got any results. I do know I fixed a bad engine mount in the process though. Unfortunately it splooged all over my workbench when I set it down on it's side and it leaked all of the fluid onto my tools. :(

oh wow i contacted XF a few months ago asking if he could do a video on oil pump noise in these engines, i just saw this link even though i check his channel all the time lol. Cant wait to watch it .

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Please can you tell me the exact oil you found best please, you said liqui moly 0w-40 and the 2 i listed above are the only 2 0w-40 i can see on their website.
Thanks

How did you get on, noticed any change in noise? From the XF video it would seem the noise indeed mostly comes from the scavenging section, so would be surprised if changing the O ring effects the noise but should definitely increase flow and oil pressure. ( may have been a good idea to have checked your oil pressure before and after changing it, using the port on the front of the oil filter housing.)
what oils have you tried and which oil have you filled it with after the new O ring?

regards

I like that guy. I do. Great help in many ways for us that actually take these things apart.

that said....

Im gonna just think Mercedes had a reason to make the pump work the way it does, and changing the gears to reduce noise (and increase flow) doesn’t make sense in 99.8% of the cases.

That first start whine adds character to the M113K AMG engine. Like a jet fighter firing up, getting ready to go into battle. :) Don't confuse warm engine whine with the power steering pump, especially with slightly raised RPM. I'm going to change the PS fluid, to see if it helps, but will probably require replacement, in 10K miles , or so.

Sorry, I posted my results in another thread. It can be found here https://mbworld.org/forums/w211-amg/...an-area-2.html

Bottom line is that it did drastically reduce the noise, but didn't quite eliminate it. It was inaudible inside the car for the first few days after the repair, but came back a bit today, which appears to be related to cold weather we are having here. Even today it is not nearly as loud as before, but enough to be slightly irritating to someone with a sensitivity to noises like myself.

Right now it is probably third on my list of hates about the car to a squeak in my dashboard and another one from the passenger headrest. LOL! I absolutely hate it when cars make sounds that they shouldn't. I've been known to spend dozens of hours tearing things apart and installing sound deadening materials just to stop 1 squeak, and at the moment I am seriously contemplating tearing the entire dash out of my car to find that damned squeak, as well as removing the passenger headrest. If there is one thing squeaking on the interior, it's basically all I can hear. It might as well be someone chewing mac and cheese with their mouth open right next to my ear. I have a problem, I know.

You can find the rest of the details in the other thread, and there is some video of the noise before and after for comparison.

ok, thanks I will move over to the other thread, funny thing is im always googling this issue but never find any threads besides this one LOL