dcho

hey all, so i have a '13 sedan and have this ticking sound that my local dealerships have not been able to fix.

the first time i heard it was a few months into ownership and it would only happen when the fuel level was low. filling up my tank would consistently make the sound go away, but then the sound became more persistent and now it can be heard at any fuel level (though still intermittently).

i can't correlate the occurrence to temperature or fuel level or any other factors so I'm pretty lost. as the ticking speeds up with rpm, both dealerships have replaced my fuel pumps but that hasn't fixed the problem. warming up and driving off doesn't seem to have an effect either. its pretty hard to hear the sound from outside of the car so I'm not sure its the ticking noise related to the lifters.

is it possible a heat shield or something is loose? it's been driving me crazy, along with all the other squeaks and rattles

any help would be greatly appreciated.

skaarlaj

Motor sound crisp, I'd guess there's an exhaust pipe moving around and coming in contact with something. I'd get her on jack stands, start her up and start looking, if you haven't already done so under the hood.

SROC276

Does the ticking go along with the rpm? Is it still there while your cruising or only in park? If you can't hear it while outside then it is something inside the car like a loose panel..the ticking sound does sound like something loose in the exhaust....maybe center brace right under neath your spot.

Jons95c36amg

This is old news. Mine has the same sounds when not driven in 3weeks. It goes away after engine warms up. Seems its normal with these monster engines.

dcho

Jons, this car is my daily driver so I hear the sounds regardless of how long it has been sitting. and like I I said, the sound doesn't go away after warming up.

SROC, the sound does speed up directly with RPMs and can be heard in Park or drive. at higher speeds the noise is drowned out by road and and engine noise. I hope it's not serious and just an excuse to get a new exhaust... heheh

dcho

hopefully it's something in the middle the car! the farther from from the engine the better. I know that sitting in the drivers seat, it sounds like it's coming from the back. but when sitting in the back it's the opposite. sigh.

Merc63

Check for something rattling. If not check engine.

Critter

Pop the hood and listen to the rear of the motor, if you do not have a mechanics stethoscope use a long screw driver, one end on your ear and the other on the valve covers starting front to back. Your noise will be close to the firewall. Could also be coming from the front of the transmission. Since you have had the dealer listen to the noise it is documented, this is good. Now have them find the source, if we can hear it then they should be able to locate the source.

jvanbrecht

Yours is new, so I doubt it is the belt, but one of my pulleys is making a similar noise, also increases with the rpm. I believe there is also a service bulletin related to noises from the belt, but that relates to hard sporty driving, and the solution is an additional guide pulley, but this came out in 2009, and according to the document;
"Additional poly0V-belt guide pulley was phased into production as of engine number 15698X 60 026271, together with modified timing case cover."

So this may not actually be your problem, but I would check the belt anyways, it might just be damaged or defective.

dcho

thanks all! any other suggestions are welcome. my SA and mb USA have seemed to abandon me on this issue. mb USA even had the audacity to send me a follow up survey asking how how they did.

abcut973

I would say the same as a rattling sound coming from the outside. If it was inside the sound would have been more pronounced and less tamed.
Have a friend pressing the throttle while you inspect the car from the outside to see if you can locate the source.

SROC276

Yes i agree have a friend rev it a little to locate the sound. Pitch is rather low and would try the center of the car under neath. Sound a lot like a loose exhaust bolt, may be right after secondary cats. Check engine cover too.

SaphGreyC63

I had a sound like that once. If you look at the exhaust around the rear wheels, there is a little silver twisted cross bar, mine was loose, just tightened it up and that solved my problem.

_timothy

your issue sounds a little different. I had a vibration/ticking sound that had a distinct metallic pitch. an exhaust bracket of some kind came loose and was making a metal on metal vibrating sound that varied based on RPMs. had to get it on a lift and tightened.

E=mC63

You're not alone. This has been happening to my 2012 a lot. Always on cold start and the noise comes from the hood. No idea why but the noise speeds up as I accelerate but I end up forgetting about the noise after I press on the gas a little and let the engine warm up. If this is a problem or if its fine to leave it I would love to figure out.