M113K engine noise

[b1g1an]

The whine on the E and CLS 55s, which is most usually incorrectly put down to the supercharger is the main oil pump as in the one that pumps your engine oil around, it's a heavy duty item with six gears apparently. You don't get it on the S55 because it has a different oil pump with only two gears. As WN says, it can't ever be the supercharger as it's not engaged with a standard clutched pulley.

It will always happen at start up and then stops after a few seconds. However, on some engines it will keep whining at low revs after an oil change and may or may not stop doing it after it's done a load of miles. I looked into it because mine started the continuous whining after it was serviced ie oil was changed.

The yanks went into great depth about this several years ago, many claiming it was the air injection pump or even coming from the transmission but someone eventually tracked it down to the engine oil pump and conducted a load of experiments with different grade oils and found it would stop and start depending on what was in the sump. However, one that was quiet with one engine wasn't with another so there isn't a 'this will definitely fix it' solution.

Apparently it does no harm but is slightly alarming if you haven't noticed it before. When I watched (listened to) that vid I couldn't hear anything like what was being described...just the oil pump

 

[Fr3ddy]

Just spoke to Jack at PCS. He said that they have had both belts off the pulleys and the noise still remains so it definitely has nothing to do with the supercharger.

They will be in contact later today with updates.

 

[ricky s]

Interested to know if there was a happy ending to this thread..? and to what was the diagnosis and the repair/fix

 

[Fr3ddy]

Interested to know if there was a happy ending to this thread..? and to what was the diagnosis and the repair/fix

Nothing actually wrong with the sc or pulleys.

Gearbox re-build, should be ready by the end of the week.

It's not quite a happy ending yet

 

[John]

Nothing actually wrong with the sc or pulleys.

Gearbox re-build, should be ready by the end of the week.

It's not quite a happy ending yet

Sh*t!

Gearboxes are quite strong so would be interested to know what caused that...

Is yours is making the same noise Ricky?

My inde reckoned around £1500 for a full gearbox rebuild from his specialist.

 

[Borys]

Guys be careful there
There are lots of treads on US forum rgds that whine noise. People getting gearboxes rebuild with no joy. They do blame oil pump for the noise
Fingers crossed diagnostic on yours is correct

 

[Fr3ddy]

I haven't got all the details yet but the torque converter welded it's self to the oil pump as if its constantly engaged. Both been replaced and the gearbox is in process of being fitted now.

When the car was lifted on the ramp you could here the noise coming from the gearbox 100%

Fingers crossed, tomorrow everything should be ok

 

[John]

Good luck!

 

[Fr3ddy]

Cheers johnEBoy

 

[merc85]

How many miles has the cls done Fr3ddy?

Finger's crossed for you btw :/

 

[Fr3ddy]

Thanks mate, she's done just under 80k

 

[BlackC55]

I have just put the box back in tonight.

Noise has gone.

It was the front pump bearing that broke up and sent metal everywhere. Ruined the torque converter too so we had that re-furbed also. The box was stripped, everything that needed replacing was replaced, valve body stripped, cleaned and tested. It all works perfectly now.

FYI the box noise is like a zizzing sound. High pitched and rev dependent. I have heard this a few times before and usually it is caused by the torque converter breaking up.

 

[merc85]

What can cause the bearing to go at 80k isn't much really is it? btw am only asking as i maybe looking for a 55k soon just getting the low down.

 

[BlackC55]

Wear and tear. No real reason for it. Same as any bearing.

Second one I have seen in 16 years, so not common

 

[BlackC55]

Also if the ATF changes have been slack in the past that will not help.

 

[Fr3ddy]

Hello Olly, you are a legend, what time did you leave the shop tonight.

Also if the ATF changes have been slack in the past that will not help.

Weird that because the ATF was changed at 40k and then at 76k. Regardless to that, s#@T happens. I cannot wait until I drive me baby again.

 

[Fr3ddy]

Wear and tear. No real reason for it. Same as any bearing.

Second one I have seen in 16 years, so not common

I have got the best luck

 

[BlackC55]

Hello Olly, you are a legend, what time did you leave the shop tonight.



Weird that because the ATF was changed at 40k and then at 76k. Regardless to that, s#@T happens. I cannot wait until I drive me baby again.

Sometimes there is no rhyme or reason as to why.

I left at about 7:30. I needed to get it done as I need the ramp space and you need your ca back. Im charging the battery for you over night as it was a bit low. Just need to road test it for a bit and do my final checks tomorrow during the day.

 

[ricky s]

Good to see PCS got to the bottom of this problem, and got it fixed, unusual issue, it was interesting and educational to read Ollie,s diagnosis. A happy ending, bar the bill, but nothings free!