JRHolt

Hey everyone,

I just had my 2006 SLK55 in for service for an unusually loud engine whine.

The shop foreman thought it was coming from the oil pump area using electronic ears. They found the oil pump chain rubbing slightly on the front timing cover. They trimmed the cover to give it clearance and replaced the oil pump and the drive chain.

The car still makes the noise

Below is an mp4 video I just made of the noise. Please let me know if your SLK55 makes the same noise. Thanks

Video Link: SLK55 Engine Whine Video

Ausmbtech

That's not right at all!

I'm interested in their diagnosis of the oil pump chain hitting the timing case. I'm a bit doubtful about that being the case because seeing the oil pump (which is a 3 stage oil pump BTW) is bolted to the block and can't move the only way I could imagine the chain hitting the timing case would be for the timing gear on the crank to have moved forward. The only way I can think it could move forward is if the crank pulley wasn't installed correctly. Either way I'm doubtful about it.

Usual noises for these engines is from the p/s pump, a/c compressor, idler pulleys and I have also seen a noisy transmission oil pump. For some reason I've found the SLK55 to have a little bit of a whine more so than any other N/A 55, not sure why, it just does.

Unfortunately noises transmit very easily to other areas and make it harder to find the source.

I would take the drivebelt off and run the engine, it will eliminate the idlers, p/s and a/c in one go. Failing that I would be leaving it with the dealer.

Yellow R1

Your car should not be making that pronounced of a whine - sounds like a belt. In fact, it's almost as if when you increase RPMs, the whine immediately increases in pitch in parallel with the peddle - but the RPM gauge "lags" the whine....ie it does not increase for 1 - 2 seconds later. Odd. Let MB fix it as your car should be under warranty.

Nice C6 BTW.

-Matt

matton

If the whine goes away after warm-up, it is normal for SLK55's. If it continues after warm-up, I would guess it is a belt and/or tensioner issue.

JRHolt

Thanks for the replies everyone

I spoke with the shop foreman and they did try running the car with the accessory belt removed and it still made the noise.

I seems to be coming from the front of the engine but I am not sure what it is yet.

They thought it was coming from the oil pump but apparently that was not it. The shop foreman said he was going to do some more research and get back to me.

I just wanted to make sure that it was not normal and thought I would check with the forum so you guys could compare your SLK55 to mine.

Thanks for your help. I will keep you guys posted

mini 280

sometimes the secondary air pump sounds very loud on these cars for some reason. next time you speak to the foreman bring it up in the conversation and see what he says. keep us updated when you fix the problem.

JRHolt

The secondary air pump is an electric pump and would not change pitch with the rpm of the engine but thank you very much for the reply

JRHolt

My suspicion is that it may be the timing chain tensioner.

The car used to make a very similar noise after start up but would go away after a few seconds. Now the noise I am hearing is much louder and remains constant no matter how long the engine runs

The timing chain tensioner is regulated by oil pressure and maybe it is not moving when the oil pressure builds up.

I will keep you guys posted. Thanks for your help

Iggy_Type_R

Hey Vette-pilot, any news on this? I have the same problem

It used to go away after warmup, now it's there all the time... just like you said...

thanks in advance!

JRHolt

Iggy_Type_R,

Sorry for not updating the thread with the results.

The dealership finally narrowed it down to the oil pump in the transmission. The weird thing was, is that it sounded like it was coming from the front of the motor.

They replaced the transmission oil pump and the loud noise I was hearing is gone!

Now I do have to admit I still hear a bit of a whine that definitely sounds like the timing chain but it is very faint and not loud like the transmission oil pump was making.

Now when I first start the car I hear the timing chain whining and it does quiet down after a few seconds but does not go away completely.

I am going to replace the timing chain tensioner soon to see if that changes anything. I will update this thread after I replace it

Iggy_Type_R

Thank you so much for the update!!! I've just emailed it off to my auto-shop - it'll get booked in for the same treatment next few days!


I wouldnt worry about the whining noise at start up, I have never driven an SLK55 (i've been in a few) that didn't have it at the start up, but went away after the revs drop after that initial warm up.

Now all i have to work out on my car is why the **** I get the CEL for right cat error when I have Kleemann cats 12 months old. Grrr

thank you again for such a prompt update!

Iggy

mini 280

could you please post the part number of the pump if its on the repair order? my car makes the same noise too but its out of warranty. If i can buy the part i'll take it to a indy shop

JRHolt

Iggy,

You are welcome

JRHolt

mini 280,

The part numbers listed on the repair order are:

Oil Pump: 722-270-01-97 (qty 1)

Screw w/coll: 004-990-23-12 (qty 17)

Gasket: 220-271-03-80 (qty 1)

Oil Filter: 221-277-01-95 (qty 1)

Good luck

Iggy_Type_R

Chaps, I have been on the phone to MB Australia for the parts and the quotes are

I found best prices at http://mbspecialist.com ... although http://www.genuinemercedesparts.com was also close.

If anyone has better suggestions please let me know

esqdg

i have the same issue i believe. https://mbworld.org/forums/slk55-r17...-attached.html

what do you guys/gals think about the sound? similar? this sound never happened until i had service b done. not sure if that is a random coincidence or not. the noise does not go away when the engine is warm.

i have been searching the threads and most say idler pulley. shrug. help pls? i am still under warranty and the local mb is also at a loss (see my thread for details)

ElPrince

Glad that you got it fixed! Im starting to hear a slight whine in my car but not sure if its actually there or me just making it up in my head.