XSNSX

Hi all,

Long time lurker, first time poster here.

Just bought a 2003 SL500 w/ 17,000 miles. Under light acceleration between 1500 to 2000 RPM, I'm getting a noise that sounds like a valve train flutter. There is a light ticking sound that accompanies this.

I was told by an MB road test technician that it might be a carbon build up. I was advised to use a detergent gasoline, such as Chevron for a couple of tanks. In addition, I also used a fuel system additive that claims to clean fuel injectors and remove carbon build-up in the heads and valves.

None of the above has made any difference. My question is... is this sound normal? If not, is this a problem anyone else has experienced?

Thanks!

SL2003driver

Did you get an extended warranty? I've read all the posts on this site and have never heard this one before. I don't have it. Use gas from either Quicktrip or Conoco. It is recommend brands by Mercedes. Has the right cleaners and is quality gas. Go to www.toptiergas.com and check it out along with a list of recommended gas.

XSNSX

Yes, I bought a 12 month Starmark warranty. The car was a CPO from Naples MB. I *thought* a CPO car would have to pass an inspection before being sold, but apparently not.

I searched MBWorld before posting my question and there was one thread that sounded similar to my own scenario. It turned out to be a faulty catalytic converter.

Although the noise sounds like it's valve train related, I can't say for sure. Anybody want to venture a guess on what this could be?

IngenereAMG

I think that the valve trains on these cars are pretty solid, but we are just guessing now. You have a warranty.......I think your best bet is to drop it off at the dealer and let them figure it out.

Aviator

XSNSX, I have seen this on a friends' SL as well. He was told the same from the dealer. I have personally been in his car ad can add this: after you accelerate hard for a couple of moments, the noise is gone. It sure had me scratching my head and all I can come up with is it probably is due to oil pressure issue.

XSNSX

The replies are greatly appreciated guys. The car is being returned to the dealer this week. I'll post the results of their inspection for future reference.

Again, I can't say it's the valve train, but it has a ticking noise noise that is directly relevant to the RPM's between 1500-2000. One more thing... first thing in the morning, when the engine is cold and for the first mile, there is no noise... just the sweet sound of a smooth, well balanced motor. As the engine warms up, this "fluttering & ticking" sound becomes noticeable. Again, only under light acceleration between 1500-2000 RPMs.

I'd like to say it's my imagination, but passengers have commented on the sound w/o my solicitation.

W219CLS55

My CLS55 has the same noise. When it's cold it sounds good but as soon as I go for a drive and stop somewhere the sound is present. I also notice it when I go to a drive through and stop at drive through window I here that cling sound coming from the engine. And i'm pretty easy on my engine. Ive had it since 65 miles it now as 10,000. My freinds s55 doesnt do it and he has 46000 miles.

XSNSX

Thanks for chiming in. Nice to know I'm not alone. I thought if others experienced the same, it would be easier to diagnose, or at least share the collective knowledge of forum members with the service technician, hopefully saving him time, but more likely... educating him when he can't figure it out on his own!

Please accept my apologies for NOT being up to speed on the CLS55, but does it share the same "basic" motor with the SL500?

Thanks again all!

W219CLS55

i think so but the only differnce is the cams and the suprcharger and the exhaust

lovemysl

I have a 2003 SL500. I get the same ticking noise at low speed. Almost sounds like a deisel engine or a bad valve. It goes away after a while. I figured this was normal. I am interested in what the dealer says

XSNSX

Nail on the head! It sounds like a muted diesel noise... exactly! However the noise is constant for me, even after 100 miles of driving.

I'll post the diagnoses as soon as I know more...

Thanks again everyone!

SL2003driver

Could be piston slap, caused by short skirted pistons. Would happen more often in cold temp's under 30 degrees, then go away as the engine warmed up.

Aviator

However, in the case of piston slap, it will be easily reproducible, cold or warm, with strong deceleration every time. Such is not the case.

Aviator

I still have an idea that it could be the oil pump or system not getting up to pressure. Is there a way to check oil pressures ?

XSNSX

It turns out the cause of the problem IS actually related to the valve train. What's the fix...? NEW MOTOR MOUNTS. The original motor mounts were hard rubber. The updated mounts are fluid filled dampeners. This isolates vibration and noise transmitted to the chassis by the engine..

I'm told by the service techs these engines are not particularly quiet motors. I'm also told the SL engines are loose tolerance because they are all aluminum, prone to more expanding and contracting then an iron block or heads, hence... more noise. (not sure I'm buying this!)

Anyhow... my problem is fixed. I have smooth running and QUIET car again.

PS: Also had the clips on the brake calipers replaced because the car was squealing constantly, or until the brakes were applied.

lovemysl

Great to hear of the fix. Mine will be going into the shop to have the mounts checked.