[fareast1]

Hi guys,

Looking for some help. My N52 is acting up. It makes a grinding noise below 1k RPM, but the noise works like a switch. It comes and goes exactly at the same point. I was thinking centrifugal force, but...

Can anyone identify this?



To be fair, this is in my X5, but nobody answered me over there. I never have that problem when I ask e90 questions...


I have a grinding sound coming from the engine any time the RPM are below 1k. At 1k, like a switch it stops. Drop below 1k and the switch turns back on. I have a couple of videos.
I thought it was the timing chain tensioner, but I just replaced that with no change.

Thanks in advance!!!

[fareast1]

...Bueller...???

[W37V]

I have no clue man... But hopefully you figure it out.

However, I think people might need more info:
So where exactly is the noise coming from? Front, rear, top, bottom? Have you tried listening with Mechanic's Stethoscope (HF sells them for $3 or broom handle also works)? Are you sure it's the engine? If you did timing chain, who did the work? Was there any difference whatsoever? Have you taken the car to any mechanic's to help you diagnose it? Do you have any codes (shadow)? If so which ones? How's oil consumption? Fuel consumption? When did this start happening and for how long now? What's the mileage on the car?

[fareast1]

Thank you W3 for the response! I was feeling a bit lonely. 😀

The noise started a few weeks ago.
It sounds like it is coming from the front part of the motor. I decided it must be caused by the timing chain tensioner which I believed was assisted with oil pressure. There was no change after replacing the tensioner.
Car has 120k miles
I have owned it for about 5 months. I have been going through it slowly. I replaced all the fluids, the rubber seals in the stepteonic, cooling system, ignition system so far. That was because I didn’t have the records, the tensioner was the only attempt at addressing the noise.

[fareast1]

I am now wondering if it could be a timing chain guide?
I hate to take it to BMW to find out, I know that would torpedo my budget.
It may be my only option though.

Thanks again

[fareast1]

Also I have had the car parked until I can figure it out. Whatever it is, it can’t be good to run it like that.

oil and fuel consumption seem normal, codes... well I have been meaning to get a scan tool...

Thanks!

[Bufalo]

Where are you located? Perhaps someone else could come by and listen in person? Hard to locate or discern the sound through just the videos other than, yeah - it comes in and out right as the tach passes the 1k mark.

[fareast1]

Hi Buffalo, I am in Southern Maryland.

I don't think it is anything with the drive belts, but am considering taking them off to see if there is any kind of a change.

I am really grasping at straws at this point.

A/C on and off has no effect.

Given the clear timing, I was hoping it would be obvious to some of the guys smarter than me on here.

Search continues

[McLarenBMW]

Have you considered the possibility of it being transmission related? Perhaps throwout bearing?

[Rmtt]

I haven't had a chance to listen to the video...i will in the morning. But I had a similar issue on a Corvette I once owned. Changed belts, pulley, tensioner....etc. It was sort if a grinding/squealing sound.

Finally figured out it was an issue with my PCV system. Not enough to cause any engine hesitation, but noisy nonetheless at certain RPM ranges.

You done anything recently that involved removing any of the brittle PCV hoses or the piece along the back of the intake?

[fareast1]

Originally Posted by McLarenBMW

Have you considered the possibility of it being transmission related? Perhaps throwout bearing?

I had not, but everything is still on the table until I can figure this out.

Thanks!

[fareast1]

Originally Posted by Rmtt

I haven't had a chance to listen to the video...i will in the morning. But I had a similar issue on a Corvette I once owned. Changed belts, pulley, tensioner....etc. It was sort if a grinding/squealing sound.

Finally figured out it was an issue with my PCV system. Not enough to cause any engine hesitation, but noisy nonetheless at certain RPM ranges.

You done anything recently that involved removing any of the brittle PCV hoses or the piece along the back of the intake?

Have not touched the PCV or any part of the vacuum system yet.

It started the day before I was going to work on the transmission, at which point all I had done was swap the fluids.

I thought it might have something to do with engine oil, and still may. The car says the oil is full. After I change the oil housing filter gasket, I will drain and measure what comes out. I hate tossing 75 bucks of oil, but if it gets me closer to solving the issue it makes sense.

I hope it turns out to be something like that. Its like nails on a chalkboard for me right now. I imagine the timing chain dragging against the aluminum every time I hear it.

Thanks RMTT!

[Bufalo]

There would be no throw out bearing on an automatic transmission vehicle like this X5.

[Rmtt]

Originally Posted by fareast1

Have not touched the PCV or any part of the vacuum system yet.

It started the day before I was going to work on the transmission, at which point all I had done was swap the fluids.

I thought it might have something to do with engine oil, and still may. The car says the oil is full. After I change the oil housing filter gasket, I will drain and measure what comes out. I hate tossing 75 bucks of oil, but if it gets me closer to solving the issue it makes sense.

I hope it turns out to be something like that. Its like nails on a chalkboard for me right now. I imagine the timing chain dragging against the aluminum every time I hear it.

Thanks RMTT!

Had a chance to listen....definetly not PCV related. Like
I said before, I had an issue once that has a slight grinding sound, but more if a squealing sound.

Now this may sound stupid, but you can buy a product called link-belt that basically allows you to make up a drive belt at any length by removing or adding links. It's pretty inexpensive, but can be used in a pinch if you ever find yourself stranded on the side of the road with a broken belt. Just need a pair of needle nose to separate the links.

Maybe remove your belt to eliminate your accessories. If the noise goes away, then you add one accessory back in at a time by adding links to the belt and use the process of elimination to see if you can isolate the noise. Shouldn't hurt as the vehicle is only running for a short period.

Also, I'm not as familiar with BMW's as I am with other cars, but does the water pump being electric come on at all times, or during certain times "mapped" in the programming?

Maybe you could do a "coolant bleed" procedure where the water pump runs without the car running to see if something is going on with the impeller or if you hear something different.

Also, have you looked at the radiator fans? I have seen them begin to flex at certain rpm's and cause interference and clearance issues on other cars once enough centrifugal force was achieved depending on how they are pitched.

Definitely sounds like some type of metal on metal contact from what I can hear. And as you mentioned before, it could be timing chain tensioners. I've seen on other cars like Audi's where the tensioners were made of an inferior Material of Construction, wear down, and cause some sloppy slapping noise. But that is generally heard at any RPM and gets louder as engine RPM goes up.

[fareast1]

HI guys, I appreciate the responses.

Looks like I need to replace the motor. I finally got around to bringing the car to an indy who found brass in the oil filter and believes the bearing is shot. So now I am shopping for a new motor.
Any suggestions on where I should look? N52

[W37V]

Originally Posted by fareast1

HI guys, I appreciate the responses.

Looks like I need to replace the motor. I finally got around to bringing the car to an indy who found brass in the oil filter and believes the bearing is shot. So now I am shopping for a new motor.
Any suggestions on where I should look? N52

Car-part.com start there. There few junk yards with n52 for sale near nova / so md.

[fareast1]

Thank you!

Whoa, those guys are expensive!!