Very Loud Rattle from Engine *With Video*
 

There is a very loud rattle coming from my engine.

It exists while idleing and gets louder the higher the RPM's.

This began after a brake bed-in procedure ( 60-10 mph) stops.
While finishing the bed in procedure, at one point the car shut off and all indicators came on. I restarted the car and it was find for 10 minutes until I came to a light.

The noise can be significantly loud when the engine is revved.

There are no indicators on the dash, other than yellow oil light that comes on after a little while of driving.

Any ideas?

Video of rattle: http://www.youtube.com/watch?v=hLlKesS283g

You check the oil level? I hope.

Is this your 4.8 or 3.0?

Did you check the oil level? By braking hard a lack of oil can occur if the level is too low, hence the noise if the hydraulic valve clearance tuning system misses oil to work properly.

Sorry Hit Redline, I didn't see your post!

This is for he 3.0. The dipstick showed very very low oil, I just added some more. After adding the oil, the sound was barely noticable upon start up and idle, the noise returned after a very short drive low rpm drive. I'm waiting for he oil to " set" before I check the level again.

With a bit of luck, this is only the hydraulic valve tappets which are empty of oil, assuming that the lost of oil pressure (during the had braking) forced the oil in the top of the engine to drop down to the pan...

There is a procedure recommended by BMW as this is something which can occur on vehicles doing very frequent short rides, (start the engine and while keeping the transmission in neutral, accelerating the engine to 2500 to 3000 rpm during 3 minutes, then letting it idling again for 5 minutes. In some cases they recommend to do that several times with a maximum of 5.), however before doing that you have to check first where the noise is located exactly.

I am not sure I have the courage to attempt the procedure you have outlined sfcl.

I am afraid that starting the engine at all maybe causing further damage etc.

You right, this is precisely why you need tolocate the noise first. On the other hand, I'd be surprised if you got heavy damages by only having a very short lack of oil pressure, unless you had extremely low oil. When an engine is restarted after an oil change and that the filter bowl is empty, it runs about 1 to 2 seconds without any oil pressure, oil light on, too. Crossed fingers for you.

The sound seems to be coming from the left hand side if the engine, top side.
The x will be sitting about a week before anything is done.

When you said low on oil did you mean it was about 2 qts low, or only had 2 qts. (which would be 5-6 qts low)

If you were just 2 qts low I wouldn't expect any engine damage. If the sound is from the engine itself I'd pull the oil filter cap off and see if it is all together properly and if it was holding oil properly etc. I've heard of cases where a non return valve comes apart and gets stuch in the oil filter housing. So check in there for any foreign parts/materials and for any signs of metal in the oil.

It doesn't sound like valvetrain noise, but sounds like it is either from the lower rotating assembly or possible the flywheel area. And since it goes away considerably when in gear there is hope that it is in the flywheel area, but it may still be in the crank/rods etc. Did you have any transmission work done recently?

I added 3 litres of oil, and that brought the oil level to the max level on the dipstick.
There has been no tranny work of anykind done recently.

The noise really seems to be internal and right at the top left side of the engine.

The noise does tick down when put into gear, but returns loud and progressively faster as you actually drive and pick up speed.

At crawl with no gas , the noise is almost non existent.

A little off topic: When changing my oil, I pour a quart of oil directly over the new filter before sealing it off. I believe this prevents the 'dry start'

:wow:Three quarts low. Luckily they have 8, but there may be some damage. I hope not.
I had the same type of sound in an all wheel drive Endeavor. I changed all belts, among other things. Finally some kid working at a tire shop found a post on a forum. It turned out my drive shaft needed to be replaced. When it was taken off at the dealership, it was broken in two placed!!!!! We could have had a serious accident. I only mention this because everyone (4 different mechanics) thought it was coming from the engine.

Does it sound like it's from the front edge of the engine, or the middle/rear?

How is your back? Did you have your surgery yet?
Congrats on the super bowl.:thumbup:

I would say left side middle to rear. Basically the area shown most in the video.

I'm thinking I should do a full oil and filter change, along with an engine flush.

My understanding is if there are metal shavings in the oil/filter then I have major problems.

I will have to do the oil change myself, because I don't want to drive the car to the dealer nor do I want to pay for a flatbed just for the oil change.

Is it whishful thinking for me to hope a full oil change and engine flush is going to solve this, or am I wasting my time?

If course I am going to the dealer at some point, I just want to be certain this isn't minor.

The video didn't load the first time I tried it. Maybe timing might be off a bit. I hope you don't have any major damage. Let us know what you find out please. Good luck

Will do, thanks for the input.


Regarding sound location:
The sound seems be coming from the area where it says BMW on the cover on the left side of the engine.

1stE53, back is still jacked up, surgery not scheduled yet... (damn HMO needs therapy to fail first)

Godfather, I'd do the oil change first (not worrying about the flush just yet) and make sure to catch the oil in a clean pan so you can take a good look at it and analyze it for any debris. You would be looking for any signs of a shiny gold colored metalic flake with a bright flashlight, and for any plastic debris to come out with it... maybe let the old oil drain through a funnel with a screen/strainer in it in case there is any debris.

And I say to do this before a flush so you can properly analyze the oil for any details/clues to the problem.

Good news,

My brother fired up the X today, the engine made the noise immediately after startup but then the noise diminished. He also revved the engine and heard nothing.

He has not taken it for a spin yet, we will wait to do the full oil change.

Oil level has dropped to minimum on the dipstick, even though I topped it up to what I thought was full a day ago. The oil does leak, but there is not 2 litres of oil on the garage floor. Perhaps the oil has seeped into the filter and entire engine, where as I didnt give it enough time before?

This gives me hope that the correct level of fresh oil will solve this problem. It also makes me cringe to think just how little oil was in the engine before I topped it up on Saturday.

Anyways, I am definitely counting on this oil change solution here.

_________

Question 1:

I have searched for "engine flush" on the forum but have found nothing.

Does anyone know how/what you do to essentially clean the inside of the engine when its empty of oil, just before adding new clean oil and filter? Products, procedure? Yay or nay?


Question 2:

Say I do find metal shavings in the old oil, but the noise goes away after the new oil change. Should I assume some damage was done, but not enough to compromise the engine, or am I not out of the woods?

i had a simliar issue with a 318 before, although oil wasn't missing. the oil pump was clog, the pick up filter was filthy. the PO must had not changed the oil ever.

IMO I would let it drain for 24 hours. Then I would pour a new quart of oil in the engine and let that drain too for another hour or so. When filling, carefully pour a quart over the oil filter before putting the lid back on it. Ensure it is good and soaked. Mine took the full 8 quarts. I stopped at 7.5 quarts to measure, all 8 went in.

Thank you for keeping us posted.

Bad news.

Copper and silver metal shavings I'm the filter.

I changed the oil and filter. The noise improved ( not detectable at idle, increases in volume with rev)

I'm now depressed. The x is going to the dealer Monday for a diagnosis.

So what am I looking at here 5-10 grand?

damn, this thread has crazy stuff in it. First off 3 qts below max is catastrophically low and I'm pretty sure your engine is toast if you took it to redline. What you had was metal to metal contact inside your engine without anything to lubricate the parts.

Second, 7.8L is the size of the windshield washer tank, not the displacement on the engine. If it were 7.8L I'd hope it have at least 700hp to boot but it'd prob only get 5mpg.

Lastly, good luck dude. Time for a new motor or rebuild it sounds.