Ok so a few weeks ago I started noticing a noise coming from the engine bay, sounds like what other described as marbles insides the engine. It only does it when at idle and up to about 1500 rpm but after that it stops as your increse rpm. Im taking it to the dealership tomorrow at 2 and droping it off. Anyone have any similar problems or anything like it. I want some what of an idea so when I go tomorrow, I can tell them what I have read it might be. It has got louder and louder and today it was pretty loud. Im starting to worry its some major internal problems. Does anyone think I should ask for a new engine? Haha, I know its a bit early to be hinting in that direction but if it comes to it....?

Any help is greatly appreciated!!

 

In absence of any other more obvious issues, the sound of marbles in the engine is detonation.

It could be a lot of things though, honestly. No way to tell without having someone savvy with engines take a look at it.

Or it could simply be marbles.

 

Just an educated guess:

water pump bearings
alternator bearings
power steering pump bearings
idler bearings

Good Luck, let us know how you make out.

 

Well, the dealership seems to think its an altenator. So a new altenator is on the way, I will let you know if that solved the problem!

Thanks guys

 

Did it solve the problem ? Was it the alternator bearings ?

 

mines started doing the same thing... just about 60K miles FWIW.

did the new alternator fix this?

 

Put a doctors stethoscope next to the alternator and you will hear the marbles rollinging around in there. I haven't the time right now to tear it apart, but the bearings can't be too difficult to find. all the other accesories sound fine, it's just the Alt. bearings.

I suggest a search over at MBZ world regarding alternator bearing failure, might find a DIY thread or something.

 

Alternator has bearings in it?? I figured it would have a bushing for the pulley, but not a bearing. If the brushes internally gone bad then you'll electrical problems along with the noise. I think I saw an alternator around 350$ for our cars. When my battery was going bad I was looking at alternators because they usually go in pairs

Justin

 

why would you put bushings on an alternator? bushings wouldn't survive longer than 30 minutes.

 

No need to tear the alternator apart. Either find a rebuilt one or buy a new one, that's the way to go.I wouldn't attempt to replace the bearings when I could put in a completely rebuilt unit. I've never had to look, but I'll bet that you could find a rebuilt one because there are a lot of our Mercedes engines out on the road.

A good way to detect bad bearings that's quite simple is to use a large screwdriver and put the blade on the alternator, while the engine is running, and put your ear to the handle. If the bearings are bad, the noise telegraphs up the handle and you can hear them rattling around. We used to use this method in the garage. Another way is to loosen the belt and spin the alternator, sometimes you can feel the grating of the bearings. Other causes of the noise could be from other devises driven by the serpentine belt such as the water pump or idler pulley or power steering pump.

I was hoping that the member who started this thread would have responded back to us after he took the car in to be repaired to let us know the outcome so that we could all learn something. Too many times I've seen posts asking for help and not giving us any feedback once their problem is solved. Good Luck with your problem. AND LET US KNOW THE OUTCOME. We need to build our data base for future searches.

 

Not all bushings are rubber or polyurethane. The bushing (or brushes) on the rotor spin inside the stator providing that AC current inside the alternator. The rectifier bridge (diode array) is what blocks out 180 degrees of the AC providing DC that all the autos electronics run on

 

Absolutely THE best way to listen for bearing noise: it's cheap, it's effective & it works just like a stethoscope. I used this to listen to printer bearings for 30 years. As long as you don't have to stick your face (& make dam_ sure your hair, shirt, tie, pants, if they're REAL baggie, are NOT going to pulled in!) next to a pulley you're good to go.

That WOULD be nice, wouldn't it !