Time for rod bearings?

[ATB88]

Welp, after 60k great miles under my ownership, I've gotten an oil analysis result that indicates it might be time for rod bearings. Would like to get community thoughts in case there's significant leeway in how these results can be interpreted. Screenshot of Blackstone report attached.

Car is a 2002 with 107k miles currently, oil was analyzed at 105k miles, so there have been 2k miles driven since the report.

I have the full BMW service history of the car since new, it underwent the BMW rod bearing recall service really early on in its life, before 20k miles, maybe even before 10k miles iirc. So there are 80k-90k miles on the current bearings and they are BMW recall replacements. I've never been clear on whether the bearings installed during the recall had any better lifetime than the original factory bearings, but it seems like 80k-90k is about the correct service interval either way?

This is my first oil analysis since 2018 when I bought the car, so no trend in metals to analyze.

13 ppm lead: does this mean that I park the car now until I can get it done? It'll be a DIY whenever I can clear a weekend.

About this oil sample: this was by far the longest I've ever run between oil changes on the car. I don't have exact numbers because I had too much going on in my life when I did the prior oil change to have written down the mileage. But my guess is that the oil being analyzed was in the engine for ~7k miles (maybe a bit more maybe a bit less). Typically I do ~3k miles, rarely up to 5k. FWIW, I had the valve cover off for a few days total during this oil interval, once for valve adjustment then again to redo timing, but I doubt that has any influence on the lead.

I'd also had an oil leak throughout this oil change interval, so I added at least 1.5 qt of oil over this period, probably more.

Given that I've driven 2k additional miles since this report: am I on borrowed time? Significant risk to drive the car any further? What makes me wonder if I'm okay is that the blackstone guy seems to be advocating that I drive another 3k and send in another sample, but that seems reckless.. no?

Thanks for your thoughts! This is something that I've been anticipating for the last 7 years and it seems it's finally here!

[sbay]

Peace of mind is the name of the game here. 80k is a sweet spot to get them done too. You can probably still drive it though just stay away from redline…

[BRiley]

So in reality, I've seen them blow out with that kind of oil analysis. And I've seen them be fine with double that. One of the intervals on your report shows 23ppm, and evidently they were fine.

I can tell you though, I spun one with 15ppm. Didn't think anything about it, since they'd only been on the car for 1700 miles. Spun anyway. Point is, like sbay said, do it for piece of mind. Just don't use BE bearings.

[ATB88]

So in reality, I've seen them blow out with that kind of oil analysis. And I've seen them be fine with double that. One of the intervals on your report shows 23ppm, and evidently they were fine.

I can tell you though, I spun one with 15ppm. Didn't think anything about it, since they'd only been on the car for 1700 miles. Spun anyway. Point is, like sbay said, do it for piece of mind. Just don't use BE bearings.

Well, I kind of wish it was a smoking gun that they're about to go out, as I'd feel more pressure to get it done ASAP rather than be tempted to keep driving it every once in a while, but that's because I'm dumb and lazy

Also, the 23 ppm on a previous report was for copper, not lead. That was from oil drained from the car the day I bought it, which I suspect had been in the car for many years while it sat (the car only say 45k miles in its first 16 years, most of those being in the earlier years), and blackstone attributed it to bronze wear in the valvetrain as it wouldn't have made sense for it to have been bearings. The lead this time around is way way higher than any previous oil analysis done on this car, but very few total analyses have ever been done relative to the number of oil changes, so who knows.

But anyway, your point remains.

[PSUEng]

Just my opinion, the Blackstone's advice on going 3K more and then test again is probably realistic because 1 data point doesn't make a trend. Now practically speaking, are you taking some risk? Sure. At 105k, if you have the resources to just do the bearings, eh, why not? Personally speaking for myself, I'd probably do the bearings because I have the (time/money) resources to do it. If you do go 3k more, please post results! I've had my Blackstone results fluctuate over the years....

[dukeofchen]

If you need the kick in the butt, I had no rod bearing history / oil test results when I bought the car, and with testing under my ownership lead steadily decreased while copper was up and down across tests. When I finally pulled the trigger every bearing was showing copper – the lead values had decreased because they were THAT gone. The final test before I pulled them showed 16ppm copper / 17ppm lead – copper had risen from 10ppm to 16ppm between oil changes at which point I decided to stop playing with fire. The thing that Blackstone tests don't shed light on is the state of the bearings on each of the 6 rods – you're only getting an average and we know based on plenty of pictures that the wear rate is not consistent for all 12 bearings in the engine. And only one needs to spin to make your life hell.

YMMV but there's the worst case, keep you up at night, scenario.

[ATB88]

Just my opinion, the Blackstone's advice on going 3K more and then test again is probably realistic because 1 data point doesn't make a trend. Now practically speaking, are you taking some risk? Sure. At 105k, if you have the resources to just do the bearings, eh, why not? Personally speaking for myself, I'd probably do the bearings because I have the (time/money) resources to do it. If you do go 3k more, please post results! I've had my Blackstone results fluctuate over the years....

Thanks for the data points. Funny that my analysts conclusion was "poor bearing wear" for numbers that were similar to yours, and I assumed you weren't getting such comments on your 70k analysis?

I've actually already done 2k out of those 3k extra miles... I'm tempted even to just do an oil change now to send in a 2k mile sample as it's most of the way there and I've got that free FCP oil. If bearing wear is happening/worsening it should show? Included in these last 2k miles are many redline pulls and even the car's first trip to Tahoe! Finally got to use the ski-bag passthrough on my vert, and had a few below-freezing cold starts last weekend... kinda hurt me to do it every time lol.

[PSUEng]

70k comments...

[ATB88]

70k comments...

Ah I see, thanks. Well at least their comments are consistent.

Everyone's right that this is about the right mileage to be doing them anyway, and my plan is definitely to do them as soon as I can, and that will hopefully be in the next month or so. In the meantime I guess I'll try to drive the beater truck more...

[ATB88]

Because I felt curious I dug up my paper copy of my car's prior life dealership service history to see when the bearings were done. Fascinatingly, it looks like they were done... *twice*??

Two separate entries in the BMW "Warranty Vehicle Inquiry" report

Date: 05/17/2003
Mileage: 8,617
Defect Code: 0011760100
Description: E46 S54 Big-end bearing

Date: 11/02/2004
Mileage: 12,607
Defect Code: 0011950100
Description: E46 S54 Replacing big-end bearing shells (2. KDB)

Seems pretty bizarre that the dealer did the bearings twice within 18 months and 4k miles? Any dealership folks know if the distinction between the defect codes on the two services means anything? Pretty curious! Maybe the first set didn't wear in properly? Either way, good to know that current bearings are sitting at 95k miles.. they're ready.

[Nate047]

Everyone basically agrees that rod bearings are a 50-100k mile maintenance item ballpark depending on circumstances. You said there are maybe 80k miles on yours. And you have owned the car long enough to put 60k of those miles on it. That means you presumably like the car and want to keep it. Why overthink it? Seems obvious.

[karter16]

Because I felt curious I dug up my paper copy of my car's prior life dealership service history to see when the bearings were done. Fascinatingly, it looks like they were done... *twice*??

Two separate entries in the BMW "Warranty Vehicle Inquiry" report

Date: 05/17/2003
Mileage: 8,617
Defect Code: 0011760100
Description: E46 S54 Big-end bearing

Date: 11/02/2004
Mileage: 12,607
Defect Code: 0011950100
Description: E46 S54 Replacing big-end bearing shells (2. KDB)

Seems pretty bizarre that the dealer did the bearings twice within 18 months and 4k miles? Any dealership folks know if the distinction between the defect codes on the two services means anything? Pretty curious! Maybe the first set didn't wear in properly? Either way, good to know that current bearings are sitting at 95k miles.. they're ready.

If your vehicle was manufactured between October 2001 and Feb 2002 it would have been subject to SIB110203 and had the bearings and oil pump replaced. It would have then also been in scope for SIB110404 and had the bearings replaced again.


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[Zekarus]

these oil tests are just time and money wasting. mine came back okay but the bearings didn't looked that great. i'm not doing oil tests any longer. regular oil changes, driving the car warm and cold and changing the bearings every 60-80k miles should be enough. these bearings are from a 116.000miles car. so yeah change your bearings asap.

[ATB88]

If your vehicle was manufactured between October 2001 and Feb 2002 it would have been subject to SIB110203 and had the bearings and oil pump replaced. It would have then also been in scope for SIB110404 and had the bearings replaced again.


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Wow older cars like mine really had them done twice? Wild! Jan 2002 manufacture date, so it checks out.

Everyone basically agrees that rod bearings are a 50-100k mile maintenance item ballpark depending on circumstances. You said there are maybe 80k miles on yours. And you have owned the car long enough to put 60k of those miles on it. That means you presumably like the car and want to keep it. Why overthink it? Seems obvious.

I'm not trying to overthink whether or not I do them, it's definitely time. I guess I'm trying to overthink whether this is a "avoid driving the car and rearrange my life to get it done immediately" situation or "keep driving the car casually and get it done in the next couple of months" situation. But the answer seems to be it's up to me ¯\_(ツ)_/¯ lol

[bmwfnatic]

I think you are at pretty much the perfect interval to do them again with your current milage delta since last change at 12.6k miles.
Especially since you didn't own the car since new and you don't know how previous owners drove it.

Just make sure that the service performed isn't a downgrade (in terms of materials used).