RJC

Started the car first thing this a.m. and for the first time since I got her I put the window down (1st day it was under 90 here) while still in the garage; put the car in reverse and during the cold start cycle I heard a racket which almost sounded like a header leak, it went away in short order but it freaked me out and sure hope it was not valve clatter. Our Touareg makes a similar sound also only during cold starts, I thought it was valve clatter but the service people showed me it was some kind of emissions device. Since I did not hear this on my CLK500 I was wondering what it was coming from on our 55's?

Thanks

red00lght

Funny you mention that. Both the CL500 and the S55 I've had just don't sound great at idle. The CL sounded like it had a valve problem (though everything was just fine) and the S55 sounds like it has sweaky belts, etc....I only noticed this like you said...in the garage upon start-up.

I found the cure was to go driving and give it some gas....problem solved!!

RJC

Hey I see you're in S Fl too, I guess this will be the last of the decent weather for a while . As I mentioned above our Touareg makes a very similar sounding clatter at cold start that I swore was valve related but we checked 5 of them at the dealer and they all did it, some kind of emissions pump/device. My E55 really sounded like it had a header leak this morning, my 04 500 made a bit of clatter during cold start but nothing like this...could it be cold supercharger noise It's amazing when the windows are closed in this car how it really quiets outside and or engine noise.

red00lght

Yeah....this has been an awesome weekend weather-wise. Last time I'll have the windows open for quite a while!

RJC

Any other's hear notice the clatter at cold start especially after the car sits overnight or longer?

Thank you.

tjcMBE55AMG

Could this be piston slap from using less than premium fuel (or other issue)?


TJC

RJC

I only use 93 octane.

I've read about a similar noise quite a bit on the different 55 forums and most say it's normal, as the Mobil 1 oil is very slippery and drains out of the hydraulic lifters, upon cold start it takes a minute or two for the lifters to pump up again and the noise is most noticible when put in gear/under load when cold. As I had mentioned, my car sat for 24 hrs and it's the first time I had the widows open in the garage at cold start up. I'll be sure to check it again in the a.m. and pay more attention to it. I'm just not familiar with all the sounds, sensations etc of the kompressor engines yet (like the cold start rough idle I just learned about here) and want to learn what's normal and what's not . This noise just seemed much more pronounced than on my 2004 CLK500 during cold start up

mclarenm8d

I'm not sure if I have the same noises in my CL55 that you are mentioning, but my CL55 sure was noisy on start-up before I had the idle RPM lowered.

I asked the technician at the dealership to pull the idle down to 550 RPM. This also impacts the idle for cold start. The car is much less noisy at idle now.

Actually, the main reason I had the idle pulled down is that my supercharger engagement comes in at a lower RPM now and the engagement is much smoother. It's a zen thing, many reasons I thought of as to how this could work, some of them operator related.

If you are at a drive through, you might want to note what noises you hear bouncing off the walls of the building when you have the window down. The supercharger pulley racket gets worse with age and detiorates rapidly. New pulleys and belt definitely help.

Did you get your 55 new or used? The technician mentioned to me that most people request that the idle be raised because the 55 is a bit thumpy at low idle (big stroke crank effect). My CL55 had actually been set to run a bit high by the previous owner.

RJC

I do notice its revs quite high at cold start and the idle is a bit rough until its warms (takes about 2-3 minutes to smooth out fully)My 55 was bought new and only has 300 miles to date. I'm not exactly sure if what I heard was lifter, emmissions devices, supercharger etc. but it's only at cold start, the car is very quiet any other time. Does the supercharger have it's own noise at cold start?

Thanks

mclarenm8d

I think the pulleys and belt for the supercharger definitely make a ton of noise. My CL55 has roughly 42K miles, when I had the pulleys and belt replaced in the mid-30K range there was a definitely improvement in the engine bay noise department.

But with your car only have 300 miles, hard for me to say or compare. My supercharger definitely makes racket with the mileage it has (even when spun by hand).

Another thought - I don't recommend this to others for possible warranty concerns, but I do know that a 55K is quieter in the engine bay with 15W50 Mobil 1 than 30 weight or 40 weight. The 55 has a long stroke and a lot of aluminum under the hood, so I've always felt that it is going to be a bit noisy. This factor would probably be more noticeable in hotter areas of the US.

Does anybody know if the 55K's come with a lighter weight from the factory before the W40 is used by the dealer at the first service?

RJC

I don't think the dealer uses straight 30 or 40w oil, they use a 0-40w mobil 1 for 2005 MY cars'+. Since I live in hot Florida I would prefer Mobil 1's 15-50w and I'll ask for it at the first oil change but they may or may not use it only the 0-40w.

RJC

Does the supercharger even spin @ idle/cold start? I wouldn't think so.

RJC

Let the 55 sit for 21 hours straight and just started it in the garage with the windows wide open; the tapping noise I heard yesterday is really quite minimal and only lasts about 30-45 seconds. I feel alot better now.