Strange rattling/knocking noise from top-end (?) - video w/ good sound

[RideThePigGir]

Title says it all. It was ever so slightly present when I bought the car at 45.3k miles, but barely audible over the usual engine and direction injection noise, so I just chalked it up to the being how the engine sounds. Since then (at 49k miles now, 1800+ of them straight highway from Phoenix to Chicago), it's gotten quite a bit more noticeable, especially as I've driven the car harder on a more regular basis, and since the ambient temps have gone from the negatives to 30-45F on average. It's slightly more prominent when I've been driving the car hard, or when the engine is heated up past the mid-point of the oil temp gauge (not often here in Chicago so far this year...), which makes me think it's has something to do with the oil heating up and losing viscosity - the oil was changed by the dealer in Arizona, so it could very well be lighter-weight oil than what BMW recommends - 5W40 full synthetic, yeah?

Also, at around 48.5k miles, after a commute to/from work in the snow that involved a lot of wheel spinning and higher revs, the Low Oil warning came on. I added a quart of Mobil 1 0W40 and the oil level has been fine since. I can't find any visible leaks, and I've tested it out by putting a flattened box under the engine after driving her hard, but the box didn't catch anything other than salt. I'm chalking it up to the usual blow-by that these engines are known for; I'll be changing the oil soon enough and installing a catch can, but I'll keep my eyes on it. Haven't noticed any other ill effects either - certainly no performance loss, still a perfect idle 99% of the time (knock on wood), and all the usual pops/burbles out of the exhaust at the usual times. Installing the intake didn't change the noise at all (only engine mod so far), and it gets noticeably quieter when I put the car in P or N.

The car is still under BMW warranty for another ~1k miles and I have an extended warranty as well, plus a small issue with the headlights "jiggling" over hard bumps that needs to be fixed - should I just take it into my dealer and have them check it out? I'm going to inadvertently grease their palms a bit with a BMW Assist purchase, and they're less of a stealership than most, so I'd imagine they wouldn't give much pushback if they have to dig deep to get to the root of the issue even though I didn't purchase the car from them.

Anyway, here's the video - sorry for the vertical letterbox crap. My phone went derpy without telling me. The sound is pretty good; that's all that matters. Any ideas/suggestions/troubleshooting would be much appreciated. Thanks in advance!

[loesch]

Sounds like somebody is using the 15,000 mile oil change interval recommendation. lol. Just for kicks, put a quart of oil in and see if the noise quiets.

[RideThePigGir]

Originally Posted by loesch

Sounds like somebody is using the 15,000 mile oil change interval recommendation. lol. Just for kicks, put a quart of oil in and see if the noise quiets.

No worries of over-filling it? The auto-gauge on the stalk has been showing halfway up the little bar and "OK" since I put in the last quart. 0W40 Mobil 1 is alright for the N54, right?

[loesch]

It's OK. That's what I use. The one that says European Formula on it. My engine is a little different being an N55 but I can hear a difference after I change the oil. The recommended intervals are plain stupid and ridiculous. These cars burn oil. I know it's weird but they do. That's why I was thinking maybe you were low. Now the more I think about it I bet your oil just needs to be changed. Maybe you should just go ahead and do an oil change and go from there. I get the filter and O rings from my local BMW dealer and the oil from Advanced Auto.

[RideThePigGir]

Originally Posted by loesch

It's OK. That's what I use. The one that says European Formula on it. My engine is a little different being an N55 but I can hear a difference after I change the oil. The recommended intervals are plain stupid and ridiculous. These cars burn oil. I know it's weird but they do. That's why I was thinking maybe you were low. Now the more I think about it I bet your oil just needs to be changed. Maybe you should just go ahead and do an oil change and go from there. I get the filter and O rings from my local BMW dealer and the oil from Advanced Auto.

I actually have seven or so quarts left of a 12'er from when they were on sale on Amazon - lucky me =)

Thanks for the advice. Any tidbits I should know about before I do the change? I have a vacuum pump I used on my last car, but I've heard it's best to change it the old fashioned way on these engines, since getting as much of the old oil out as possible is crucial. Any credence to that theory?

[loesch]

I'm not familiar with the vacuum pump idea. I can't really help you out there. You may want to invest in a BMW oil filter wrench before hand. Just makes it easier. Also it is sometimes really hard to pull the filter out of the housing once out of the car. You just gotta yank on it till it comes off. Also people argue about which direction to install the new filter. I think the general consensus is to put it in with the lettering facing up.

[Venom]

Originally Posted by loesch

Sounds like somebody is using the 15,000 mile oil change interval recommendation. lol. Just for kicks, put a quart of oil in and see if the noise quiets.

Sorry for the offtopic OP.

To loesch: I am curious about why you would run n54 mids on an N55.

[Dackelone]

You should take your car to BMW and have them document that your having low oil pressure problems. This will help you down the road IF your engine blows up. IF you don't document it now... you could be SOL down the road. Have them do an oil change for you - just for your peace of mind.

[loesch]

Originally Posted by Venom

Sorry for the offtopic OP.

To loesch: I am curious about why you would run n54 mids on an N55.

I did that because the exhaust was way too raspy and loud. The smell also was bothering me. Someone gladly swapped me for my N55 pipe. I've always wondered exactly how much power difference it makes.

[Venom]

Ah interesting. The mids aren't terribly restrictive if memory serves.

Originally Posted by loesch

I did that because the exhaust was way too raspy and loud. The smell also was bothering me. Someone gladly swapped me for my N55 pipe. I've always wondered exactly how much power difference it makes.

[RideThePigGir]

Originally Posted by Dackelone

You should take your car to BMW and have them document that your having low oil pressure problems. This will help you down the road IF your engine blows up. IF you don't document it now... you could be SOL down the road. Have them do an oil change for you - just for your peace of mind.

Very good point. No matter how detailed my personal maintenance log is, the dealer isn't going to give a shit if I throw a rod or shoot a piston through the oil pan.

And besides, that greases their palms a little bit more for now - and makes them think that I'll continue bringing it to them for basic service - so that they're nice and easy to deal with (and get a good loaner car from) when my water pump/HPFP/etc decides to kick the bucket

[RideThePigGir]

Originally Posted by loesch

I did that because the exhaust was way too raspy and loud. The smell also was bothering me. Someone gladly swapped me for my N55 pipe. I've always wondered exactly how much power difference it makes.

No worries about thread-jacking - we're all friendly here

I've actually heard quite a few sound samples of people with N55s using N54 mids in various installs and I prefer the sound too. How much do the mids affect the smell coming into the cabin, or is it more through open windows?

[RimasRS]

Could it be chain tensioneer or AC?

[RideThePigGir]

Pardon my ignorance, but... "chain tensioner?" Don't our cars have timing belts, not chains?

[loesch]

Originally Posted by RideThePigGir

No worries about thread-jacking - we're all friendly here

I've actually heard quite a few sound samples of people with N55s using N54 mids in various installs and I prefer the sound too. How much do the mids affect the smell coming into the cabin, or is it more through open windows?

The problem before was smell coming through the open windows. Now it is virtually stock unless you are following me when I really get on it. The sound is perfect in my opinion.

[Dackelone]

Originally Posted by RideThePigGir

Pardon my ignorance, but... "chain tensioner?" Don't our cars have timing belts, not chains?

We have a timing chain that drives the engine(crankshaft to camshafts). No rubber timing belt.

We do have a poly ribbed (rubber)belt to power the alternator, ac and ps. It would be relatively easy to remove the poly belt and start the car to see if your noise goes away.

[RideThePigGir]

Originally Posted by Dackelone

We have a timing chain that drives the engine(crankshaft to camshafts). No rubber timing belt.

We do have a poly ribbed (rubber)belt to power the alternator, ac and ps. It would be relatively easy to remove the poly belt and start the car to see if your noise goes away.

Thanks for the info. I'll definitely try and get the belt off this weekend to see if it gets rid of the noise.

[johngrossi]

Have you removed your engine cover or cowl recently? The foam on the underside of the engine cover can get folded over and expose a lot more of that di injector noise

[RideThePigGir]

Could it be the death throes of my water pump? I've had some really strange behaviour from my HVAC system blowing cool/cold air while set at 77-79f, with the engine already at operating temperature. The coolant level is just fine.

[RideThePigGir]

Originally Posted by johngrossi

Have you removed your engine cover or cowl recently? The foam on the underside of the engine cover can get folded over and expose a lot more of that di injector noise

Haven't even taken it off. Yet

[johngrossi]

Well I'm local I could help you take a peek at it sometime this weekend if you'd like

[RimasRS]

Originally Posted by Dackelone

We have a timing chain that drives the engine(crankshaft to camshafts). No rubber timing belt.

We do have a poly ribbed (rubber)belt to power the alternator, ac and ps. It would be relatively easy to remove the poly belt and start the car to see if your noise goes away.

There is also chain tensioneer hydraulic bolt which goes to engine from turbo side, another thing which should be serviced.