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'13 BMW X3 2.8i New Engine Sound

My friend owns a '13 BMW X3 with the 2.0-liter turbocharged engine. It has about 50K miles on it and it has been properly maintained by the dealer. It recently developed a new sound. The dealer claims to have listened to it, as has another shop we use, and they can’t hear it. But we can hear it very clearly. Can I get a reality check?

  • It seems related to engine RPM. The sound is a high-pitched whine. My gut tells me it is the turbocharger’s bearings. But I’m a worrier. We can hear it inside the cabin when we drive with the HVAC fan off and audio off. No codes according to the dealer. Is this the dreaded “just out of warranty” profitability-enhancement noise we are starting to hear? Or are we just nuts? Seriously considering trading this thing in for a new crossover before it bites. What would you do?

Have your friend and you tried listening under the hood to try to identify where it’s coming from?

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I did, but solo, and the engine in that thing is pretty noisy (direct injection maybe?). I will try again with her giving it gas to see if I can get a location. Thanks for the suggestion.

Sometimes listening through a paper towel tube or similar, and pointing it to various components, can help isolate the location.
Touching individual components with a metal rod and allowing the sound waves to propagate up the rod can help too.
There’s also a device called a “mechanic’s stethoscope” that amplifies the soundwaves with a diaphragm and feeds them into earpieces that can help. They’re cheap, and worth the price.

But when feeling around with rods, be careful. Stick a metal rod into a spinning component and you could end up having it pulled out of your forehead!

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Fuel injectors can make a high pitched whining noise. Just in normal operation. Most noticeable during acceleration b/c it’s louder and you can hear the pitch change. I had a Bosch CIS equipped VW Rabbit years ago that made this noise, noticed after I had the car several years. Turns out it had probably been making the noise all along, but I hadn’t noticed it. Let me ask you this: If you aren’t actually listening for that noise, would you notice it? If not, it’s probably the normal fuel injector high pitched whine.

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Nothing beats a set of mechanics ears for this kind of problem. They are sensitive enough to hear subtle variations in the sounds of injectors operating or separating the noise of a bearing from the rest of the cacophony going on under the hood. They only pick up the direct vibrations through the clips…

Yeah, that or a stethoscope with an extension

The direct injection I’ve heard sounds more like the clacking from a diesel, not a whine.

The ears are nice because you don’t have to draw straws to see who will ride along under the hood to locate that elusive noise that happens only while driving :astonished:

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Aw, where’s the fun in that?:smile:

Great ideas. I am planning to give it a good listen with my GF applying throttle this weekend and will check back in if I can pinpoint the area from which the sound is coming. Thanks again.

Thanks, folks. I gave it a listen this week while the engine was being revved. The advice about tools for better listening are much appreciated. I don’t want to waste members’ time, but I have recorded it here on Youtube if anyone cares to have a listen. I think it is time to trade this vehicle anyway, but if anyone hears anything they think they can identify (along the lines of a high-pitched, RPM-related whine) feel free to weigh in if interested. Thanks

Sounds like a pulley noise, that noise is directly linked to engine speed. Remove the drive belt, run the engine and see if the noise is gone. If the noise was from the turbocharger the sound would change in relation to exhaust flow and impeller speed, not exactly the same as the engine speed.

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I agree, was thinking bearing noise from an alternator, water pump, belt tensioner or something. Although, I’ve never owned a turbocharged vehicle so I have no idea what a worn turbo would sound like when revved at idle.

Thanks again. Much appreciated folks.