What do failing rod bearings sound like?

[Cubieman]

If you have rod bearing(s) that are bad or on the way out is there any particular sounds they typically make? I know if you spun one you would likely hear a terrible noise.

[Obioban]

Once they’ve started making noise, you’ve almost certainly damaged your crank— $$$. You should not wait for a noise to replace them or you’ll be very sad you did.

But, sounds like knocking.

[Cubieman]

OK, I've got a new noise, kind of a "whirring" or slight rattle sound sometimes at about 2.5k and can't identify it. Definitely not a knocking sound.
Rod bearings are on my list with 64k on the car, Beisan first this summer than maybe rod bearings this fall/Winter.

[Ruley]

In some instances they sound like a hole in the block.

[Cubieman]

So whats up with the rod bearing recall cars 01-mid 03? What was the issue?
At what point would one want to preventatively address the rod bearings? I know that may be a difficult question to answer as no two engines are treated the same.

[SG/IRM3]

OK, I've got a new noise, kind of a "whirring" or slight rattle sound sometimes at about 2.5k and can't identify it. Definitely not a knocking sound.
Rod bearings are on my list with 64k on the car, Beisan first this summer than maybe rod bearings this fall/Winter.

The whirring noise I heard at lower RPMs turned out to be five intake cam bolts cut in half with the sixth and remaining one cut halfway thru. I never really had the marbles in a can sound some described but it was noisy in the RPM range you're hearing the noise - but not excessively noisy. That was at 47k miles and over three years and 13k miles ago. I did the full Beisan treatment and no issues since.

[COVID-19]

So whats up with the rod bearing recall cars? Mine never had a recall on the rods (06/2004), from what I understand the rod bearing recall was only on earlier cars and something was done to address the problem. At what point would one want to preventatively address the rod bearings? I know that may be a difficult question to answer as no two engines are treated the same.

I believe your problem might be more towards a vanos. I got mine done around 44k and noise went away (too much play on pump). I just did my bearings at 60k and two were slightly showing copper. Mine is an 06. I think Bmw “service action” was just to buy time.

[Cubieman]

Well I'll be doing the Vanos within the next month or so and maybe that will address the noise. I edited my previous post as I read a blurb about the recall cars. The noise isn't loud, and doesn't sound particularly "bad", just a new engine noise that has developed recently.

[ethan]

Well I'll be doing the Vanos within the next month or so and maybe that will address the noise. I edited my previous post as I read a blurb about the recall cars. The noise isn't loud, and doesn't sound particularly "bad", just a new engine noise that has developed recently.

Only takes a couple hours to put eyes on that stuff if you're hearing something that ain't right. Good excuse to adjust your valves while you're at it.

[Speed Monkey]

It sounds like money flying out of your wallet....
😆 🤪

[Cubieman]

Yea, I just bought all the BMW vanos stuff minus the valve cover gasket and associated plug gaskets as I already had them from recently buying a valve adjustment kit + a nice micrometer. That was $330, now I have all the Beisan stuff + core charges to buy. Today I also had to buy a new Motronic DME for my 3.2 911 with a tune ($795), oh boy I don't make enough to mess with these car, unless I do ALL the work on my own and even then its tight.

Oh yeah I just finished installing a CSL Intake with new DME and tune. Also ordered the parts for c pillar window trim, misc. flap wiring. I need my Turner airbox to come in ASAP so I can sell it and get some $ back into my account.

And after all that the rod bearings are still in question potentially. I should have done the preventative stuff before my mods. Although after doing the mods it
made me more interested on working on the car and learning more about what may go wrong and what to address before it goes wrong.

[NYCE46M3]

Speaking from experience who just got them done, there was 0 difference between the bearings are good and the are on the way out. In the span of about 6,000 miles (my annual mileage) oil change, I went from all good to particles in the oil and strongly recommended to get them done. There was no sounds or performance changes. An oil analysis is your best bet and as you would imagine, if there are metal specs, flakes, etc. in the oil it's most likely the issue.

If you have rod bearing(s) that are bad or on the way out is there any particular sounds they typically make? I know if you spun one you would likely hear a terrible noise.

[grannyknot]

It sounds like WUMP, WUMP, WUMP

[Cubieman]

I have an oil sample I took (midstream etc.) but its about a month old now, just been sitting at room temp. Is there any real issue with letting a sample sit before sending it in for analysis?

[ATB88]

I have an oil sample I took (midstream etc.) but its about a month old now, just been sitting at room temp. Is there any real issue with letting a sample sit before sending it in for analysis?

I asked blackstone about this once and they said it's fine, but it's worth making a note of it on the form that you send in with it.