Rod Bearings & VANOS, Late 2025 Edition

[Phillies8008]

In a general sense, what should I expect to pay in late 2025 for rod bearing replacement and VANOS service on a 2006 Z4M? Just wondering what other people are seeing these days so I'm prepared to not have my eyes fall out of my head when I see the quote, lol.

Also, I know that the rod bearings are a gotta-do-it-before-fails thing, but what about VANOS? Is it something that you can hold off on until there's an actual problem, or like the rod bearings, is that just going to make the issue worse? I don't mind (too much) spending the money, but I also don't want to spend it today if I can wait until tomorrow without any particularly ill-effects. I'm going to do an oil analysis the next time I change it, but my understanding is that I really need to see a trend over time, so one analysis isn't going to be particularly helpful for deciding right now with regards to the bearings.

I've read differing opinions at to whether the later S54s were remedied of this problem, and to what extent. What's the consensus seem to be?

Unfortunately, I don't have a full service history for the vehicle so I don't know if the bearings have ever been replaced. I'd prefer not to find out the hard way, lol.

SE (SC) United States, about 102,000 miles, btw.

Thanks for any insight!

[maupineda]

Both, RB and Vanos are issues that have been over hyped by the internet community.

In your case, I would do a Vanos test using ISTA as well as an oil pressure test. If OK, look elsewhere. At 100k+ miles I would do RB.

[vt100]

Originally Posted by maupineda

Both, RB and Vanos are issues that have been over hyped by the internet community.

In your case, I would do a Vanos test using ISTA as well as an oil pressure test. If OK, look elsewhere. At 100k+ miles I would do RB.

Not sure I'd agree about over hype... That's the case when it's better to "be safe than sorry", IMO
In both cases the consequences of these failures are catastrophic for the engine, even if it's rare.

Also, vanos oil pressure test won't show anything in case vanos bolts are loose already or the chain guide is about to get broken.

PS: once these things are addressed and new bearings are broken in - keep driving the car hard. AFAIK, rod bearings fail way more often on garage queens and lightly driven cars rather than those that are tracked hard

[Efthreeoh]

Originally Posted by vt100

Not sure I'd agree about over hype... That's the case when it's better to "be safe than sorry", IMO
In both cases the consequences of these failures are catastrophic for the engine, even if it's rare.

Also, vanos oil pressure test won't show anything in case vanos bolts are loose already or the chain guide is about to get broken.

PS: once these things are addressed and new bearings are broken in - keep driving the car hard. AFAIK, rod bearings fail way more often on garage queens and lightly driven cars rather than those that are tracked hard

I've never met a BMW that doesn't like to be driven hard. That dates back to the E21.

[vt100]

Originally Posted by Efthreeoh

I've never met a BMW that doesn't like to be driven hard. That dates back to the E21.

Haha, true! Though it's especially important with these high revving S-engines

[Finnegan]

If you saw the bearings out of my 75,000 mile Z4M with an S 54, my wife’s Z4M with 50,000 miles, my friend’s S54 M3, or another friend E90 M3 I don’t think you’d say the rod bearing issue was “overhyped.” I don’t have the pictures handy, but let’s just say they’re not pretty - lots of copper and severe scoring.

I consider it a routine maintenance item at 50,000 miles. I had a Vanos hub break at about 50,000 miles, and that’s not uncommon with other friends of mine. Again, best thought of as a maintenance item.

Certainly, you can wait for catastrophic failure, but that’s a much more expensive proposition.

[maupineda]

Just because there is copper showing it does not mean they are fully done, you would need proper analysis to see how much of the copper layers is left. This layer is the main working layer and the thickest (0.2 to 0.5mm) , there are other thinner layers added for conformability and shelf life, but these are much thinner will tend to last much less. the copper layer is as thick as the carrying metal shell.

I am not disagreeing with the "maintenance" of them, but they are not spark plugs either.

[wdb]

Originally Posted by Phillies8008

In a general sense, what should I expect to pay in late 2025 for rod bearing replacement and VANOS service on a 2006 Z4M? Just wondering what other people are seeing these days so I'm prepared to not have my eyes fall out of my head when I see the quote, lol.

Also, I know that the rod bearings are a gotta-do-it-before-fails thing, but what about VANOS? Is it something that you can hold off on until there's an actual problem, or like the rod bearings, is that just going to make the issue worse? I don't mind (too much) spending the money, but I also don't want to spend it today if I can wait until tomorrow without any particularly ill-effects. I'm going to do an oil analysis the next time I change it, but my understanding is that I really need to see a trend over time, so one analysis isn't going to be particularly helpful for deciding right now with regards to the bearings.

I've read differing opinions at to whether the later S54s were remedied of this problem, and to what extent. What's the consensus seem to be?

Unfortunately, I don't have a full service history for the vehicle so I don't know if the bearings have ever been replaced. I'd prefer not to find out the hard way, lol.

SE (SC) United States, about 102,000 miles, btw.

Thanks for any insight!

I'm surprised at my Z4 cohorts for not actually answering your questions and instead going straight into "yes it is! no it isn't!!" mode. Here's my take.

Rod bearings or VANOS having excessive wear or outright failure can both cause financially dire results if not dealt with. Having them both checked out at over 100K miles is a no-brainer. Especially since you have no maintenance history for the car. Set your own baseline.

IMO the information out there regarding later engines having solved the rod bearing issue is more BMW hype than fact. It may well be true that early S54's were worse. That doesn't make later engines perfect, it just makes them less of a ticking grenade and more of a maintenance issue.

Used oil analysis (UOA) can be useful immediately, such as if the rod bearings are into the copper.

I can't help you with how much to pay except to say that paying more to a proven, well known professional is going to give you a lot more confidence than paying less to Freddy at the service center down the street. It may also depend on how much deferred maintenance is present at teardown. Find someone competent.

Enjoy the car! Easy warmup is your friend; the instrumentation helps with this. Once the engine oil is warm, let 'er rip. The gearbox doesn't love to be slammed although some folks do.

[Phillies8008]

Originally Posted by wdb

I'm surprised at my Z4 cohorts for not actually answering your questions and instead going straight into "yes it is! no it isn't!!" mode. Here's my take.

Rod bearings or VANOS having excessive wear or outright failure can both cause financially dire results if not dealt with. Having them both checked out at over 100K miles is a no-brainer. Especially since you have no maintenance history for the car. Set your own baseline.

IMO the information out there regarding later engines having solved the rod bearing issue is more BMW hype than fact. It may well be true that early S54's were worse. That doesn't make later engines perfect, it just makes them less of a ticking grenade and more of a maintenance issue.

Used oil analysis (UOA) can be useful immediately, such as if the rod bearings are into the copper.

I can't help you with how much to pay except to say that paying more to a proven, well known professional is going to give you a lot more confidence than paying less to Freddy at the service center down the street. It may also depend on how much deferred maintenance is present at teardown. Find someone competent.

Enjoy the car! Easy warmup is your friend; the instrumentation helps with this. Once the engine oil is warm, let 'er rip. The gearbox doesn't love to be slammed although some folks do.

Thanks so much! They're both something I'm going to do, and soon – probably in the next month or so. Even if BMW mitigated the rod bearing issue to some degree, I'd honestly rather have the peace of mind knowing that it's done and that I'm not driving a ticking time bomb. I don't really drive it all that much, have been very careful to let it warm up before driving, and don't get on it hard, for the most part. Luckily, I've got several BMW-specific indies in my area, and use the one that's pretty much universally recommended by the other guys in my local BMWCCA chapter. The only guy with this specific engine, in an M3, did it himself, so I was just trying to get some vague idea what I was looking at cost-wise. I'm definitely not a DIY guy anywhere close to the level of doing it myself, unfortunately. To some degree the cost doesn't really matter, because it's getting done either way. As most have said, pay now or pay later – just depends on how many zeros you want on the bill.

I've already had the alternator replaced (it failed) as well as all of the fluids. The belts and hoses were in good shape, having been replaced not all that long ago, so after the rod bearings and VANOS I'm going to tackle the bushings. My guy said they're okay for now, but sooner or later I'll want to replace them. No huge hurry. Otherwise, it appears to be in good condition mechanically. I also have relocating the convertible motor on the list – that one I've had the pleasure of doing before, so I should be good there. Cosmetically it's in very good shape – I've just been refurbishing small things, fixing a few small rock chips, etc. In my ever so humble opinion, it looks pretty damned great, though it could use a professional paint correction. It's shines up nicely, but there's still stuff I'd like someone more competent than me to address. One of these days...

I had a 3.0i before this, and as much fun as it was, the M is just in another league. It's funny: I have an M40i ordered, so the logical (and probably intelligent, lol) thing to do would be to sell the M this Spring. But I just can't bear the thought of parting with it – it's such an amazingly fun little car with so much raw personality; it doesn't care about being anything other than a sports car. I guess maybe I'd sell it if I found myself just never driving it, but I don't foresee that being the case...

Unsurprisingly, my wife doesn't quite seem to quite appreciate this logic, lol. But it wouldn't be the first time

Thanks to all for the replies – very much appreciated!

[bosstones]

Def get it done or at least keep up with oil analysis. My understanding is that a change was made but the problem still exists. For the longest time, I was the only Moupe where I work. I left for a few and came back to someone else having one! Yes, we geeked out.

Unfortunately, he thought the problem had heen solved as he was told so when he got his '06. He no longer has the car since he found out the hard way that, indeed, rod bearings still require attention.

I don't think I've ever seen specific guidance on what ppm is too much but I also figure that everyone's tolerance for seeing climbing lead and/or copper levels is different.