Z4-forum.com

Hi All,

I'm toying with the idea of buying a Z4M roadster. I currently own an S2000, which I have had for almost 18 years and enjoyed most of the ownership experience. I originally set out to change it for a TVR Chim, but although I'd like to buy into the TVR ownership experience (certainly every owner I've spoken to has been very friendly and helpful), I just can't get my head around the total lack of crash safety and the cost of good Chims compared to a Z4M.
It will be a second car, garaged and only used for a couple thousand miles a year at most.
I've read quit a few negative things about the S54 engine which is putting me off a little bit. My question is - are there many people on here who do all their own maintenance? How easy is it to work on? Are there any tasks that are just not realistic for a home mechanic to complete? The only times my S2000 goes to a garage is for an MOT, tyres and four wheel alignments (and to buy petrol obviously). Apart from that, I've done all the servicing and repairs over the last 18 years and it gets far more tlc than the standard service schedule work require. I am not however a professional trained mechanic.
Is there a lot of information on DIY maintenance for the Z4M?
Is the S54 engine really as unreliable as the internet would suggest? How many of the common faults were ironed out by the time the engine made it's way into a Z4?

Thanks in advance for any replies.

S54 and Z4M application is probably one of the last easy to DIY platforms from BMW, after F chassis generations it really got more complex

Issues with the S54 certainly do occur but like anything on the net, you only ever hear the bad.

The main issues are

Rod bearings - they do tend to wear and there are some horror stories but there are plenty of places capable of changing them. There are photos of good bearings at 130k and knackered ones at 40k so it’s a bit of a lottery. As a general observation, many seem to change them between 75-100k miles. Cost £1k +\-

Vanos - total failures come from 2 points (exhaust hub and cam bolts, the latter were upgraded and many Z4M have them already-MY 2007 was once reckoned to be the changeover but I’ve heard that contested by a good specialist) but it’s not so common. I think £1-1.5k for a full rebuild and preventative fix.

Camshaft/cam follower wear - not hugely common but a few have suffered. An expensive fix, potentially into the £000’s but no known preventative solution.

Head gasket - not heard of one going for some time now but occasionally they do. They’re nothing like the old K-series engines though, nowhere near! Not sure on cost but it will be 4 figures-everything is!

Other than that they’re bulletproof

Best advice is a gentle warm up with low load and revs-like anyone with half an ounce of mechanical sympathy would do.

As for maintenance, brakes, suspension (simpler than the S2000) bushes etc are all largely standard fare, so if you can do general work on the S2000, you’ll be fine on the Z4M.

On the engine side, as the s54 is identical to the M3 (bar a revised bolt or two), so there’s lots of info on the more model specific tasks like valve adjustments (easy) through to vanos rebuilds (much more involved).

Other than that, it’s skinned knuckles and swearing just like any other car!

The schedule for servicing goes
Oil service
Inspection 1
Oil service
Inspection 2

With the normal bi-yearly brake fluid change.

Inspection services are quite costly as they include all fluids, valve adjustments and spark plugs (though some of these may be specific to one inspection or the other, I can’t remember off hand.)

Typically, service history is highly prized in these cars despite them being nearly 20 years old. Many buyers want to see a nice set of specialist stamps in the book so if you’re self servicing make sure you keep receipts/photos for everything. I’ve seen plenty of cars discussed and largely rejected if they’ve gone years without decent evidence of services.

Advantages - They tend to be second cars so rust isn’t such a big concern. Certainly nowhere near the rusty frame issues on TVRs or the self disassembling E46 M3

Disadvantages - Being a rare-ish car, the choice and availability of new/used parts is much less than more common cars and parts will probably be more than the S2000.

I can’t think of anything else that’s particularly odd or unique to the cars that would cause issue. They aren’t a risk free car but then very few of this segment truly are. Look for a good history, a good owner and budget for a bit of preventative maintenance and you shouldn’t go far wrong.

Z4's in general are easy to work on and easy to maintain - the space in the engine bay is enormous. Beanie has pretty much summer it up really, the only thing I would add is buy on condition primarily (a car in good condition will show it has been looked after and will be reflected in the SH) Don't get hung up on the running in service that should have been done at around 1300 miles - if a car has done 50k then it is safe to say all is fine, again a properly maintained car will have this but don't miss out on a car if this was overlooked or wasn't recorded in the service book.
Vanos servicing isn't beyond the reach of a competent home mechanic either, just make sure you take plenty of advice and only use BMW timing tools if you decide to do it. Rod bearings are the same however, rolling around on a garage floor isn't to everyone's liking.
Things like oil changes, diff and gearbox, brake pads and disks along with suspension are easy jobs and actually very satisfying to do yourself. If you do jobs yourself always keep the receipts and document with photographs if you can as it's nice to build a folder and offer peace of mind to a future owner if you do decide to sell.

As you expect the Honda being Japanese is pretty bulletproof a Z4 requires more attention, especially the Z4M which has special maintenence needs, you won’t have gained any maintenence experience with an S2000. The E85s are now 15yrs old at least, replacements are going to be needed, I suggest a 3.0si is going to be less demanding to own and costs around half a Z4M.

Hold on a second wrote: ↑Tue Mar 26, 2024 11:50 pm Is there a lot of information on DIY maintenance for the Z4M?

There is a lot of good info on the S54/E46 M3 platform, so any DIY you need, you can reference the E46 M3 and apply to the Z4M. So far working on the Z4M has been fairly straight forward (Insp II w/ shims, diff rebuild, suspension). Tackling the VANOS today and there's nothing particularly scary about that as there is so much info online to guide you.

I've had a few Z4s now. Ignore comments suggesting to just get a non-M if you're after something truly special. You can make a non-M look just as good, handle just as well/better, but you can't get the engine and the difference between the two makes the N52/M54 rather dull.

The only thing I’ll add to the good posts already is despite a full or not service history you have no idea how it’s been driven between services. Some think as it’s serviced on time it’s ok to rag the engine from cold or redline it at every opportunity, some molly coddle them thinking they’re made of cheese, you just don’t know, so all you can do really is do the usual checks, see how the seller treats the car on a test run, especially from cold, and go from there. If it ticks over steadily and is in good general condition then you decide, not much else you can do. Personally I’d be looking at the rod bearings around 70k + mark for wear, it’s preventative maintenance.
Best of luck if you go for it, they’re on their own in terms of quirky and unique, and as Simon says, a 3.0si Z is a cracking car, but can’t hold a candle to an M in terms of overall experience.

Thanks for replies everyone.
I've been doing a bit more homework today and am genuinely shocked at the cost of some parts, especially brake discs. At least at 2K miles per year it won't be a constantly recurring cost. Tax is a bit of a pain as well, but probably fairly insignificant compared to the higher maintenance cost.
It looks like budgeting for rod bearings and vanos upgrade fairly soon after purchase would be a good idea. I'm quite happy working under a car on axle stands for some things, but I wouldn't fancy doing the bearings while lying on my back.
I'd already decided to rule out any non-M Z4. I want something that is going to be a bit special and hopefully hold it's value fairly well. I had thought about a newer 35i manual as an alternative but there aren't really many manual ones around plus reviews of it being much more of a softer GT car also put me off.
My task for Easter weekend is to get a few niggly little things finished on my S2000 then I'll start having a look at some of the ones being advertised. As always, the best ones seem miles away!

There’s a few nice ones for sale on AT at the moment - it would be worth asking on here before going to see as there may be someone who has seen them or is nearby and can view for you.

I know of a superb Coupe and Roadster for sale

Hope you find a nice one. Dont worry too much about the few horror stories that are out there, its a great engine and absolutely magic platform. If you love the S2k, which you do, youll love this too. Go into ownership without looking back, its special. Couple of things the boys have already mentioned, warm her up properly before stepping on the loud pedal and youll be good as gold. enjoy and welcome!

Hi and welcome to the forum.

I'd echo what lucasdiniz said too after having two 3.0Sis before I got my M, although you have already decided it has to be an M - the S54 engine is really special.

I had my rod bearing shells replaced at 78K because I didn't know the cars' history and with 7 previous keepers there was a strong likelihood one or more may have ragged it from cold. The upper shells were all showing copper so I was glad I did! The engine mounts were also well past their best so it's probably best to replace them at the same time while the cross-member is off.

It has now done 91K and still puts a smile on my face every time I drive it.

It's not surprising there aren't too many local to you as the UK only got 614 of them! Mine was 140 miles away, but the drive home more than made up for it.

Feel I might have some useful input here.

I've owned lots and lots of the usual cheaper end 2 seat sports cars - stacks of Mazdas, MR2, Boxster, Elise etc etc and my current car is a higher mileage 2006 M Roadster. I have also experience of S2000, TVRs, etc etc Like you - the only time my cars go into a garage is once a year for £45 MOT. I have rebuilt engines, resprayed cars, built and tuned ECUs, etc etc, all at home.

This time round it was a toss-up between a Chim and the Z4M - I was looking specifically to get something with a more characterful engine. I bought mine 12 months ago, drove it till Autumn 'as is' and then parked it up to try work through a bunch of stuff bringing it up to scratch.

My car has just emerged from the garage where over winter I've done a whole bunch of stuff - all the fluids, every regular service item, cooling system refresh, VANOS bits, engine mounts, gearbox mounts, exhaust mounts, a whole host of tiding up of the underside, touching up some missing paint, rustproofing etc etc.

Its my first BMW, the car is really nice to work on, fasteners appear generally good quality, access is good, engine access is very good and easy, and depsite not having any previous experience with BMW i've managed to easily and cheaply get myself setup with all the diagnostics stuff (INPA etc) which is joyful compared to trying to do Porsche Diagnostics at home!

Theres stacks of generic Z4 info available, and everything else M (S54 engine) specific is generally available on the M3 forums etc

To summarise - yes, its good car for someone like you, as you sound much like me.


Finally - don't get a regular car. They are simply not characterful or interesting enough. The S54, steering, the looks, and the subtle changes are what makes the car interesting. I would reccomend a 986 Boxster over a 2.5 or 3.0 Z4 all day every day - with the Z4M, your buying the engine and getting the rest of the car for free.

Particularly as somene coming from an S2000 where the incredible engine dominates. You can quite easily imagine the Z4M as being an 'S3200' !

There are things you can do before preventative maintenance. Vanos for example is something that’s bounded around as a must do but often it isn’t. BMW has a vanos test procedure and decent specialist will be able to do it. Had mine done twice and it was within tolerance both times. This is a good indication but hesitation and a lul between 2-3k revs can be an indicator.

Hesitation can also be throttle position sensors can be out of sync you will find a lot of threads on S54 hesitation and essentially swapping out the 3 sensors is a quick and easy fix.

A lot is internet scaremongering I’ve had 2 since 2011 and have only seen 4 engines that have failed in that time. 3 were heavily tracked and the 4th after having some work done the cooling system wasn’t put back together properly and overheated while being delivered and the driver didn’t notice and needed a rebuild.

The S54 is incredibly reliable considering like the S2000 it delivers over 100hp per litre naturally aspirated and tolerances being so low!

The main issue with the Z is because they haven’t appreciated and the maintenance costs are high you can be in negative equity quickly. An inspection, disks set of tyres can be 3-4k off the bat so make sure all consumables have been done to ensure costs are mitigated. If this is the case doing the bigger things makes the car more desirable come sell time.

Other elements like rod bearings should be considered at around 80k. At the same time engine and gearbox mounts as these perish and at up to 18 years old they will be perished and can make a big difference as the drive train can move a little on and off acceleration.

Suspension isn’t the Zs best suit either, crashy ride and the struts also being up to 18 years old if not visibly leaking, the gas will have escaped meaning dampening is poor increasing the poor ride attributes. Springs are renowned for breaking but again this is accentuated by struts not dampening and the springs taking a lot more hammer. Thankfully it’s relatively an easy fix and there are lots of options.

Again a lot of this isn’t the fault of the Z it’s just down to age and wear. All worth knowing about for negotiation and finding the right car

They are a really rewarding car and with a couple of subtle mods punch way above their weight with a good cabin, modern enough with engaging manual gages etc

There’s not much on the market that ticks as many boxes. Enjoy the search!

Hold on a second wrote: ↑Tue Mar 26, 2024 11:50 pm Hi All,

I'm toying with the idea of buying a Z4M roadster. I currently own an S2000, which I have had for almost 18 years and enjoyed most of the ownership experience. I originally set out to change it for a TVR Chim, but although I'd like to buy into the TVR ownership experience (certainly every owner I've spoken to has been very friendly and helpful), I just can't get my head around the total lack of crash safety and the cost of good Chims compared to a Z4M.
It will be a second car, garaged and only used for a couple thousand miles a year at most.
I've read quit a few negative things about the S54 engine which is putting me off a little bit. My question is - are there many people on here who do all their own maintenance? How easy is it to work on? Are there any tasks that are just not realistic for a home mechanic to complete? The only times my S2000 goes to a garage is for an MOT, tyres and four wheel alignments (and to buy petrol obviously). Apart from that, I've done all the servicing and repairs over the last 18 years and it gets far more tlc than the standard service schedule work require. I am not however a professional trained mechanic.
Is there a lot of information on DIY maintenance for the Z4M?
Is the S54 engine really as unreliable as the internet would suggest? How many of the common faults were ironed out by the time the engine made it's way into a Z4?

Thanks in advance for any replies.

I'm not sure how old this thread is, but honestly I wouldn't be scared by maintenance on them, especially if you buy a good one. As others have said, warming up gently and decent servicing and they are reliable. most of the suspension bits you can get for not crazy money as well as some of it is actually just E46 3 series stuff.

I know Simon3.2 has 2 of his for sale and I'm now selling my M Roadster. I'm not sure on Simons cars but mine has had rod bearings & vanos done as well as an inspection 1 service recently which went all good. So it's a case of buying right, rather than cheap

BMWs of this vintage are probably the best cars for a DIY mechanic. Access is excellent, they're designed really well to be pulled apart and put back together again, and the quality of fasteners is far superior to say your average French or Japanese car of the same age. Due to the numbers of E46s on the road most E85/86 oily bits are still easily sourced, although some trim and bodywork can be difficult to track down.

There are a few jobs such as rod bearings and VANOS that are probably best left to specialists, of which there are many dotted over the country, but 90% of jobs can be tackled by an enthusiast.