I'm a newbie and recently purchased an '02 C240.

I have noticed, after the engine heats up, a ticking sound from the engine that speeds up as I accelerate. The engine will also idle a little rough but performance doesn't seem to be affected. I only notice it in 1rst and 2nd gear. I've read elsewhere that switching to a synthetic oil can help with ticking but I'm not sure they are addressing the same problem I'm having.

I'm taking it to the dealership to have it looked at but I'd like to have an idea of what it is ahead of time. Does anyone have any ideas?

Thanks!

 

Switching to synthetic??

Your car should already have synthetic. Synthetic is what's prescribed for your car.

It does not matter syn or dino oil you have in your engine, if you put heavier oil, non-major valve clickings tend to go away.

However, some people report louder valve noise with heavier oil because the valves have to struggle more and thus make louder noise.

So...there are a thousand theories floating out there.

Hope...nothing's seriously wrong with your car. Remember, Benz are not the quietest cars around. Want a quiet one, should have bought a Lexus.

 

I've only had the car for a couple of weeks and the dealer never mentioned that it required synthetic - learn something new every day.

If the dealer doesn't find anything then I guess I'll try a heavier oil.

Thanks for the response.

 

It could be an exhaust leak.

 

I hope not but it now I'm glad I decided to buy the extended warranty.

 

Could be your purge valve.
Do you use premium gas?

 

My 99 C280 V6 has the same tick since the day I bought it, I had two dealers, check it out and two very good independant shops. all came back as it is normal for these engines. I even wrote Mercedes and received the same answer. One person on another board suggested I remove an rectangle restrictor that is under the plastic engine cover and is connected to the back of the intake froom the air cleaner. It only purpose to is restiect air flow. But the other end is connected to nothing, it just sits on top of the engine. I did disconnect it and could not find any rubber plug large enought to plug the hole in the intake. I didn't want to use duck tape, even thou you wouldn't see it. But my realy concern is yes it restricts air flow and I found out inside the box is like a muffler the air comes in on is routed to once side and goes around to the other and is mixed and forced back into the intake. When I read this story it sounded like Alice in wonderland had OD'd but that was the only explanation anyone offered. Unless our resident MB person know what this plastic box is for. One thing I do know on the insurance parts sheet it shows restrictor and that is it.

I was also told if I am not burning any oil, which I don't, not a drop. Not to worry at all. One thing I couldn't determine, and probably cause I didn't asked, what caused the tick? Also, mine stops as soon as the car is set in motion I ran a rubber hose thru the firewall and conneted to a what do you call it that doctor use to listen to your heart and lungs, but the mechanic kind has a needle probe and as soon as you start the tick is gone. So, I don't even concern myself with it any longer. One last point, my 450SLC at idle is quieter as far as these types of noises then the 99 V6. The 450 has 115K miles and the 99 52K miles

 

Mine has the same ticking sound...and I've learned to forget it.

Not only that...if you raise the hood and start the engine cold in the morning, you will hear a lot of heavy clickings. I believe they have to do with the cycling of engine coolants. I stop worrying because the car is doing fine.

 

Aluminum engines click alot. The sound resonates more than in the iron horse engines. It sounds like the old worn tappet sound and causes unease these days because more and more engines have aluminum heads and blocks or just heads.

The box you removed sounds (no pun intended) like a baffle that's used on all air intakes that keeps the rushing air from sounding like a vacuum cleaner on steroids. That's why you hear the loud sucking sound when you buy a high-flow intake that doesn't use a baffle.

 

My wife put regular in the first time but it's been only premium since then.