High Pitched Whining Noise in Engine 2007 X3

[lgrandst]

Hi, New here today, I have 3 BMW's and love them. This is my oldest one 2007 X3, 210K miles and today it started having this extremely loud screaming whine in engine after about 10 min of driving. Doesn't happen when pressing the accellerator, only in park or ideling at a red light. No service code came on. No recent oil change last one done in September during inspection. Thinking a belt??

Any ideas?? Thanks Lisa

[shogun]

Open the hood and check around, at least you can find out the location, front, rear, top, bottom etc, and sometimes a mechanics stethoscope is a great help.
Just have to be careful with them, be sure not to touch any moving parts if you are looking for a pulley noise when the engine is running. You touch something moving and you'll get one heck of a blast of noise in your ears! Noises will also resonate through other parts so make sure you check multiple places to see where the noise is the loudest. For example you may put it on the ball joint and hear it creaking but it could be a seized tierod end and resonating through the spindle and still hearing it in the ball joint.
It is a fascinating tool that amplifies mechanical sound with startling intensity, and it is really remarkable to bring out sounds not heard with the unaided ear.
However, the range of sounds that come through the stethoscope is so large, and so many things are heard, because metal transmits sound so well, then a diagnosis is generally confounding and not any better than a knowledgeable unaided ear.

[lgrandst]

Hi. Thank you for the help. I will pop the hood this morning to get a better idea of where the noise may be coming from. I've heard about the Stethoscope and will consider that too.

[YouAllEverybody]

Sorry to revive a dead thread, but I have this same vehicle and it's having the exact same issue. Just curious if you were able to resolve it, or if anyone has had and resolved a similar issue? Thanks!

[shadowpuck]

are we talking about an X3 3.0si?

if so, when the problem is happening, check for excessive suction on the oil filler cap.

we fought this problem on a friend's 3.0si x3 and it was excessive crankcase vacuum - the real culprit looked to be lack of regular oil changes by previous owner(s).

also, check to make sure the pre-strainer is inside the oil filter.

[bmwdirtracer]

On the N-5x engine, the very first thing I would do is make sure that the belt is not starting to ride off the end of the tensioner pulley.

IFthe pulley has begun to tilt, ever so slightly, then the belt starts to protrude slightly beyond the pulley's edge. If the belt slides off that pulley, it can costs you THOUSANDS of dollars, and perhaps ruin the engine. (The belt gets caught behind the harmonic balancer, cuts through the crank seal, deposits tons of rubber in the oil pan, then undoes the crankshaft main bolt, which releases the timing between crankshaft and cams. And of course that can bend the valves.

[YouAllEverybody]

Thanks for the replies. It is indeed an X3 3.0si. I checked after driving home from work, and there is quite a lot of suction on the oil filler cap. I will have to go check on the oil filter and the belt. Out of curiosity, how did you wind up repairing the problem on your friends X3, shadowpuck?

[shadowpuck]

be sure and pay attention to dirtracer's comments - that's a serious issue.

in the case i was speaking of - we found the engine severely gunked up (technical term). it all started with what i described as a dog whistle that would go away if we opened the oil filler cap while the engine ran.

it was nasty - whomever let this happen should be forced to walk everywhere for the rest of their days.
i think we ended up having to replace a bunch of parts (due to the sludge from extended interval oil changes). he also had to run very short change intervals for about a year after we manually cleaned out as much of the top end as we could. we didn't want to run any cleaners through the engine as we were afraid a bit of sludge would lodge someplace important.

in the end, after doing all that the car ran much better but would still act up every once in a while. i found a TSB that talked about the pre-strainer (basically a round cage) which is installed inside the oil filter and how it could cause running issues and set an SES (i forget the code exactly). so, next time we changed the oil we noticed, sure enough, that little part was missing! installed the part and the car has run almost like a brand new vehicle for years now.

[YouAllEverybody]

Ok, thanks for the info. I will be sure to check the belts / pulleys. The car didn't make the noise this morning but was running a little rough at low RPM and the Service Engine light came on.

I'm ashamed to say that I made the rookie mistake of trusting the used car dealer and not having a mechanic look at it first (I've only owned it 4 days now), since I had just moved and didn't have a car. Everything seemed fine on the test drive and looking over it, but clearly there was more than meets the eye. It came with a 3 month/3,000 mile third party warranty, but who knows if any of this would actually be covered. I appreciate your guys' input!

[bmwdirtracer]

The running rough and check engine light would point towards the crankcase vent issues or other intake system leak, as shadowpuck indicated.

You might want to consider buying a good BMW specific scan tool, which will likely save you tons of money in the future, because you'll know what's REALLY going on with your car.

ECS tuning sells one for ~$200, which reads BMW specific codes from every computer in your car, and can even command certain computers for testing purposes.

[YouAllEverybody]

That's good advice, thanks. I will definitely look into getting a BMW specific scan tool. I figured the problem could be the PCV, based on other forum reports. Apparently it is built into the valve cover though, which I'm sure is going to be a pain if I have to replace the whole thing...