Z4 Buyers Guide


This guide is the most detailed and accurate I have ever come across, I have searched the net, spoke to experts and written the definitive guide to the Z4 for a potential purchaser.

About the car and its history

Great to drive, fast and beautifully built, the Z4 was offered with a selection of strong engines and a choice of coupe or roadster body styles. While there are cheaper sports cars out there, none offers the range of talents available from the Z4 – although Porsche’s Boxster is arguably a better all-rounder. However, the BMW is more affordable to buy and run and more practical too. BMW dealers are also among the best around, so while you pay for the privilege of running a Z4, few cars are as satisfying to own.

We Like                               We Don’t Like
Dynamics                             High purchase costs
Build quality                        Marmite styling

One of the most sensible choices in the Z4 is the 2.2i, which still gets you to 60mph in 7.7 seconds and yet costs less to fuel and insure than the bigger sixes. It’s not exactly in the Boxster camp though and in this respect the 3.0 is the one to have. With 231bhp on tap, it rockets the 1,365kg Z4 to 62mph in 5.9 seconds compared to 6.9 seconds for the Boxster 2.5.

The running gear for the Z4 was lifted pretty much wholesale from the E46 3-Series and this brings both good and bad news. The good news is that the M54 engines are really very reliable, the only issues generally being individual components like coil packs or camshaft sensors.

The variable intake manifold (DISA) system can fail, a rattle from the inlet manifold sometimes signifying the plastic components have broken up. You’ll generally notice a lack of top-end power or low-end torque (or both) depending on the position in which it has failed.

Camshaft sensors are a common failure point, symptoms being a gradually worsening hesitation and an engine which takes a second or two longer to catch when warm. It’s an easy DIY swap but advice is to use a genuine BMW replacement as after market sensors are not well regarded.

The 3-litre does like to use a bit of oil and it’s a common discussion point among 330ci owners too. BMW’s official line is that a tolerance of 1 litre per 1,000 miles is permissible and perhaps the most sensible advice we’ve heard on the subject came from a BMW independent who suggested thinking of it as being like a race engine which will use a bit of oil without there being anything wrong with it. The issue is definitely worse when the cars are used on only short trips with a cold engine and in general it seems the harder you drive them the less oil they use.

One other issue concerning the oil system surrounds the crankcase breather valve on the underneath of the manifold: this can get clogged up, along with its various pipes, and make the car smoke like an old Montego minicab. It’s straightforward and relatively inexpensive to fix but you’ll need to remove the manifold – don’t believe all those Americans on forums showing you how to do it with the manifold in place. We covered the job with Paddock Motors in our April 2011 issue.

The six-speed manual, the Steptronic auto or the SMG are the transmission options. The manual is much as you’d expect, although the six-speeder can be a little notchy compared to the older five-speed boxes and barring any odd noises you shouldn’t find anything to worry about.

The automatic is the usual refined ZF HP19 five-speed and although it cuts the 0-62mph time of the 3.0i down to 6.2 seconds it suits the car nicely and still keeps the BMW well ahead of the Tiptronic-equipped Boxster at 7.6 seconds. In automatic form the 3.0i still feels like a quick car and you won’t regret choosing it if you spend much time in traffic.

As for the SMG, it’s a tricky one. The SMG set-up fitted to the Z4 wasn’t the same system found in the M3 and is rather less desirable. The speed of its shifts is impressive and when you’re pressing on it’s fine, but the automatic mode leaves a lot to be desired: its jerky progress soon becomes tiresome and sadly it’s not a patch on the DSG box in an Audi TT.

The chassis of the Z4 is pretty much E46 3-Series, which in the main is good news. A pull on the steering wheel when you tap the brakes gently in traffic suggests the bushes where one or both front lower wishbones bolts to the bodyshell may need replacing, while any clonks at low speeds point to anti-roll bar drop links. A patter over broken surfaces can mean a balljoint needs replacing. The Z4 can also break coil springs just like the 3-Series, but on the rear at least, they’re pretty easy to change without special tools.

Pre-2004 cars could suffer with a problem which caused the electric power steering system to become stiff around the centre position when it heated up after an hour’s driving. The full cure was to replace the rack but a BMW independent will know where to lubricate the column to solve it.

Key Dates  
3/03    The Z4 supersedes the Z3.
4/05    A new entry-level model is unveiled, the 2.0-litre.
1/06    A high-power 3.0-litre engine arrives, the 265bhp 3.0si. Also, the Z4M debuts, with a 343bhp 3.2-litre engine.
3/06    A coupe edition of the Z4 appears, with a choice of 265bhp 3.0 or 343bhp 3.2-litre petrol engines.
8/06    A high-power 2.5-litre engine joins the range, the 218bhp 2.5si.
3/08    The Edition Exclusive and Edition Sport specials arrive, limited to 300 apiece and available only with the 2.0-litre petrol engine.
5/09    An all-new Z4 coupé-cabriolet arrives.



Standard wheels get kerbed easily; after market items are even more damage-prone.
If the engine runs erratically it could be because the ECU needs reprogramming or an ignition coil may need to be replaced.
If the automatic wipers fail, a new windscreen is needed.
Oil consumption can be high, so make sure the engine isn’t running on empty.

Do all the controls, switches and displays work properly?
Take a several music CDs with you and check operation, if a boot multi player check this works as well
Try the radio – if steering wheel controls fitted check their function.
Check the A/C works (an expensive repair) – for older vehicles ask if it has been re-gassed recently
Do all the lights work? Get someone to stand behind and check the brake lights/rear fog light indicators etc
Are the carpets and seats all dry? If not, is there a leak?
Does the wear on the interior reflect the mileage – high wear low mileage WALK AWAY
Check the foot pedal rubbers – excessive wear in comparison to recorded mileage may indicate something is wrong, brand new rubbers may indicate a fastidious owner or trying to cover up high mileage.
Check the ashtrays – is it a smokers car! If the ashtray is clean ASK! A new ashtray can disguise the fact that its a ‘smokers’ car. If you are a non smoker the smell will give it away and can impact on resale value.
If Sat Nav (GPS) fitted check it works and the maps/software up-to-date (BMW updates are expensive!)
Look for a tamper dot in the mileage display which means the mileage shown does not correspond with the ECU/ key mileage recordings .

Ask if the vehicle has been subject of ANY bodywork repair – not an issue if repairs have been done properly but a negotiating point. Remember, they do not have to tell you, unless you ask.
Is the bodywork free from dents, scratches and rust?
Check panel fit on all panels for signs of accident repair – look for over spray on hidden parts (under the wheel arches on rubber trim)
Make sure you do not check the car in the wet or the dark, as you are more likely to miss problems. If it’s in someone’s garage check it in the daylight
Squat down and look along the sides of the car to help you spot mild dents or accident damage
Gently pull back rubber seals around windows. Is the paintwork free from over-spray and suspect repair signs?
Look for signs of additional layers of paint, or ill-matching spray marks where an additional layer of paint has been added but the finish is not right. These are signs of an accident repair or potentially covering up corrosion
Open the boot (trunk) and bonnet (hood). Is the metal work in good condition? Wherever there is exposed metal you need to look for ill-matching colours or buckling, these can be signs of accident damage.
If a Roadster try the roof – up and down smoothly. Has the roof motor been replaced.
Does the rear de-mister work – look for elements that are not working, complete new roof required to replace! (Ouch…..)
Check the number plates (registration plate). Are they original (original dealers name on the bottom of the plate) or replacements. Replacements may indicate an accident replacement.


With proper servicing, engines are generally trouble-free. Poor running or a rattle from the top end of the engine could point to problems with the ‘Double Vanos’ variable valve timing unit. There are specialists out there that can supply rebuilt units, but a new one from BMW is over £1,000.
Before you start the car open the bonnet (hood) and feel if the engine is warm – owners may well start and run the engine prior to your arrival to ensure it starts OK and which could potentially mask engine issues. If it’s the car for you return the next day (if possible) and start from cold – remember it’s your money!
Is the exhaust smoke-free when the engine is warm? If not, there may be a problem
Is the coolant reservoir full of brightly coloured coolant? It should not be empty or brown. If not, are there any leaks that need further inspection?
Is there plenty of clean oil in the engine?
Take filler cap off and look for signs of emulsion (white/yellow gel) which may indicate head gasket problems – not a common issue on BMs but worth a quick check
Have a good look at the engine and securing bolts – bolts with rounded heads or signs of excessive over tightening may indicate issues with servicing and repair
Check service history and documentation – BMW is probably best if a car under 3 years old but not essential (there are some excellent independents out there)
Note: BMW will help confirm history if you provide reg. number and VIN
Check for a valid MOT (UK) – will assist in confirming mileage, if less than a year insist on a full year MOT (this at least will give you an up-to-date check on mechanical condition)
Link to DOT MOT register (UK): http://motinfo.direct.gov.uk
Check brakes/pads for wear (when were they last changed)
When was brake fluid last changed (every 2 years)?
Check the excise license (tax disc) details exactly match the car and number (registration) plates
Tyres – good tread left and all tyres match (are they quality tyres or cheap options)
Z4s have had coil spring failure – have any been replaced (if not they may need it in the future) The road springs have been known to snap at 35-45k, so check the car sits level and there are no rattles from the corners when driving. Some owners fit uprated Eibach springs.

Make sure you check the hood, both condition and operation. Repairs or replacement are hugely expensive with even the most basic arrangement costing over £3,000 at main dealer prices. Those with a special lining will cost considerably more. Water leaks have been known to finish off the hood motor – this sits in a special well which should be water tight but blocked drainage tubes can allow water to collect around the motor. The part alone is over £500 and the hood needs to come off to replace it so you can imagine the labour bill. If the hood is down when you go to inspect a car, make sure you see it working.

Wear in the front suspension wishbone joints and bushes will lead to vague steering and a tendency to tramline. Not hugely expensive to fix but consider fitting uprated replacements to protect against future problems.

There can be a problem with the electric steering system, leading to inconsistent response or a sticky feeling. There is a fix for this using the later steering ECU, but unfortunately it is an integral part of the steering rack and so the whole unit has to be replaced.

Creaking from the rear can be worn anti-roll bar bushes, but they are reasonably cheap to replace.

Niggling electrical problems can occur, most notably affecting the alarm and wiper mechanism. The latter can lead to the wipers not parking properly or stopping altogether. It may be just a linkage problem but a replacement wiper motor is around £280 from a franchised dealer. Misting inside the headlamp covers can be caused by poor sealing – new covers are fairly cheap.
If you have access to a ramp get underneath and check round for signs of damage and general condition
For older cars – has it had a new battery?
If XENON lights fitted do they self level?

Take the car for a good drive (1/2 hour) and at least until it has reached normal operating temperature – this may well reveal leaks etc not apparent on a short run
Does the car drive in a straight line when you loosen your grip on the wheel?
Gearbox operation – smooth and precise with no gear change difficulties (manual/automatic/paddles)
Is the steering accurate and free from play or judder?
Does the car pull away and brake easily without any noises or judder?
Under hard breaking does the car come to a halt in a straight line or pull to the left or right
Warning lights should all extinguish when car is started
Cruise control if fitted – does it work?
If a manual car accelerate to about 35-40mph and change into top gear – accelerate and see if the pull away is smooth or there is some engine judder. Not a definitive check but judder may indicate coil, ignition or injector issues
You can check if the vehicle is insured (but not the full details on the MID database – http://ownvehicle.askmid.com/askmid.aspx

If there are any get them thrown in for the price of the car – don’t pay extra for them
Ensure fitted accessories are legal in terms of fit, form and function
BMW accessories are better than other after market accessories in terms of resale value – if BMW parts have been replaced does the owner have the original BMW parts (if so get them thrown in for no cost)

MV2 was standard with sport models, and look nice (most people think).
108 was a cost option from new, basically a minimalist 5 spoke.

Follow the instructions to get a dealer style list of options fitted to the car from new. Go to:


>Owner area >Genuine BMW Parts >Parts catalogue [read on screen instructions for log in] > Enter VIN > Click on options at the top of the page, and expand the ‘Vehicle information’ tab at the top for colour and trim options

Ask if it’s ever been involved in an accident and get details included on any sales invoice. There are several examples of second-hand vehicle sales receipt on the Internet, take one with you just in case the seller doesn’t have one prepared
A vehicle which has been subject to proper accident repairs should not prevent purchase but KNOW THIS before you make an offer
HPI checks (or similar) for private deals are worth doing and should reveal any serious/insurance reported accident history. If you are a member of an Auto club (RAC/AA or similar) check with them as you may be able to get a free or reduced price vehicle check
If the car has a current BMW guarantee then its transferable but if it has an after market one can that be transferred?

If buying from a dealer GO THROUGH THE SAME CHECKS, do not be fobbed off with the ‘101 point pre service check’ routine etc
When was it last serviced – ask for a full service before delivery CHECK the service book. If they haven’t got it ask why
If the dealer offers a warranty, how much and for how long.
Check what it covers – does it cover the roof motor, YES or NO, accept nothing less than a straight response
Does it cover wheel corrosion, cracks etc. Again straight answers. Many will state, ‘On a case by case basis’, not acceptable
Ask to see the warranty terms and conditions – take them away and read them
Finance- Dealers can deal on finance rates the higher they go the more money they make – try and knock off 2% and then negotiate
Try and get the next service thrown in free – if you don’t ask you don’t get!
Remember an oil service is required every 2 years irrespective of mileage so ‘A Full Service History’ may only be mileage based and not time based CHECK as it could affect a warranty
Ask for details of the previous keeper and call them – ask what £s they p/exed the vehicle for and its history.






Z4 (e85/e86) FAQ

Hello folks, for any newbies browsing or those who may not yet know some of the little things about their cars, I’ve compiled a Frequently Asked Question Section. Please read before posting in case your question has been asked a million times before! There is also a very handy Search function on the forum – most points have been discussed in detail.

[*] The Z4 e85 was launched in 2002, with the first cars being delivered in early 2003 with either a 2.5i or 3.0i M54 engine, with a 2.2i 6cyl coming later. Later an Alpina Z4 was launched with an enlarged version of the 3.0i. You could choose a 6 speed manual, 5/6 Speed Steptronic and on the 3.0i prefacelift, an SMG gearbox. It was offered in SE trim, which was later renamed to just “i”.
[*] Before the existence of the Z4M, the wonderfully rare Alpina Roadster S was launched, powered by an enlarged 3.4-litre version of BMW’s previous-generation M3 straight-six, the hand-built motor trades ultimate power for a hearty slab of mid-range torque, but still packs a handy 295bhp punch. In Lux Spec this adds Nav, Cruise, Xenons and 19″ wheels.
[*] In 2006 the Z4 was face-lifted with new engines, a 2.0i, 2.5i, 2.5si, 3.0si and the launch of the 3.2i Z4M. The face-lift model is easily recognized by revised headlamps and tail lamps. These were available in SE or Sport trim.
[*] Also new for the face-lift was the e86 Coupé model, available in the UK with a 3.0si and /M 3.2i.

In 2009 the E89 Z4 was launched with a folding hardtop. This is covered in depth in this forum.

Here is an exhaustive list of UK Specifications, options & engine differences from the original brochures, post pre and post face-lift. Here’s a great post listing the types of wheel available too.

If you are new to this forum and have just bought a Zed – please introduce yourself in the Newbie forum.
If you are looking to buy, very well looked after Zeds are often For Sale in the Buy and Sell section.

Did you know?
[*] Holding down the Unlock key on the key fob will lower the roof (or windows on a Coupe). This seems to be model dependent although it’s not clear which years don’t work. Here is a list of options.
[*] Due to safety, you cannot raise it by default but you can get your key coded (with lots of other options) by an Independent Specialist with Autologic to do this
[*] Pulling the left indicator stalk towards you before exiting the car will give “follow home” headlights which turn off after a default 30 seconds.
[*] If you have a BLACK Radio/Stereo in your Zed it will play MP3 CDs, if it’s grey it won’t. The changeover was late 2005 – you can swap these but you will either want to swap the front from the old unit or buy more vents, to make them match.
[*] The Standard Z4 aerial can be replaced with a smaller “stubby” from either Mangowalk or an official Peugeot part. This can have a limited affect on radio signal.
[*] 3.0 Z4’s had a Sound Generator, this can be retrofitted
[*] Standard Z4 Runflat tyres have advantages but often significantly degrade the ride. Many members have swapped these for Falken 452’s or newer generation Runflats. If you do, you’ll either need a spare wheel, or possibly from the Z4M – the M Mobility Kit.
[*] Roadster Z4s will have a space for a wind deflector between the roll hoops. If this was a factory option it can be stored in the panel under the boot lid.
[*] On the Roadster you should also have Coat Hooks inside the Roll Hoops. Move the seat forward to hang things on them.
[*] All Zeds have an adaptive throttle, which you can reset.
[*] Pressing your DSC button briefly engages DST, allowing slightly more wheel spin. Pressing and holding turns off all aids and is not advisable.
[*] Some Z4’s have optional Electrically folding exterior door mirrors. If yours don’t fold electrically, they *will* fold manually but it’s not obvious – look at the crease lines carefully and you will see.
[*] If you have one of the very earliest 2003 cars, most options can be retrofitted easily as the wiring looms for most optional extras (eg electric seats, cruise) are present. Later cars had equipment specific wiring.
[*] Cleaning your roof (as most have fold marks) can give good results, depending on the products used.

Common Faults
[*] Here is an excellent link to all the Service Information Bulletins (SIBs) for the E85/E86/M.
[*] All Z4s have a high failure rate on rear springs. Good news is, it’s a relatively cheap replacement.
[*] You can reset your one touch window open / close (if active) like this
[*] On Roadsters, the drains will need cleaning which if left will corrode your roof motor, with substantial repair bills. This apparently forms part of Inspection I & Inspection II, but check with your dealer this has been checked.
[*] If your roof motor has failed, expect large repair bills from a dealer (£1000+). Shipkiller has kindly documented his replacement which will make this lots cheaper, as well as how to remove the roof.
[*] Facelift Zeds have a sealed roof motor to limit this problem.
[*] If you have an ODB2 lead you can list any stored faults, the definitive list is of these codes is here.
[*] All Z4s have a Clutch Delay Valve, which can give the effect of “kangarooing” in 1st/2nd gear. This can be removed by you or an specialist.
[*] If you have an illuminated Airbag light, it’s likely your door airbags were disconnected without the battery being removed, but there have also been occasions of failing seat occupancy sensors which cause this.
[*] Failing electric windows are often due to Window Regulators – telltale sign is a rattly door.
[*] Sticky / Non-working wipers? Check out this excellent thread.

[*] Cruise Control depending on the model year of the car is an excellent value addition. On an /M this is much trickier.
[*] Navigation is a big job but can be done for around £500. Thread is here
[*] Blue-tooth is possible with OEM parts and you should expect to pay about £400.
[*] There is also the retrofit of the TV Module, both analogue and digital.
[*] You can retrofit Interior Mood lighting, also with LEDs.
[*] Wind deflector Retrofit
[*] Multifunction buttons can also be added to the steering wheel to control audio / blue-tooth.
[*] Replacing light clusters with face-lift versions is tricky, especially at the back as you will need a new Light Control Module.
[*] Automatic gearboxes can have steering wheel paddles added, as per the post-face lift.

Audio, Nav & Bluetooth
[*] Up to date Bluetooth Compatibility List
[*] Post 2007 cars have an auxilliary in, (for MP3 Players). This is an easy retrofit.
[*] For more useful Ipod Integration (particularly if you have NAV), the favorite seems to be the Intravee, but there is also Dension, and the BMW unit which both have mixed reviews.
[*] There are 3 Audio options in the Z4. Basic, Hifi and DSP (Carver/Logic7). Basic has 6 speakers & no amp (with 8 visible grills), Hifi has 10 speakers with an optical amp, and DSP is the Carver system with 10 speakers, optical amp and DSP settings you can change. If you have cubby boxes behind the seats you have basic, if you have DSP settings you have the DSP, anything else you have the Hifi option. Anything other than the Basic Hifi is incredibly difficult to upgrade. Carver was the original Launch top Hifi named after the company that designed the Speakers, after 2007 it became the Logic7 system, all have Phillips Speakers.
[*] Several members (including myself) have upgraded the Audio, there’s a thread with good pictures here, and another here.
[*] If you have a black head unit (not dark grey) it should play MP3 CDs, & your changer should too – This was from approx Oct 05 If not you can swap the head unit, and either buy new vents or replace the fascia to the gray one.
[*] CD Changer retrofit is tricky as you have to remove lots of the rear centre console, most elect for an ipod install as this is far easier.
[*] If you have NAV you will have TMC, a traffic info alert. This will be green when not using the radio, meaning it’s receiving updates. It does this usually from Classic FM.
[*] If you have lost your pairing code for bluetooth, you can lift the carpet and find it on a label on the module.
[*] To pair bluetooth, you need to press the button on the inside of the “flap” – not the steering wheel button.
[*] OEM Nav can have it’s firmware upgraded (latest is v32) which will allow 3d Perspective Mode, (avail from about v27 in 2006) but this is hidden.
[*] Perspective mode is accessed from a hidden menu: if you have firmware v29+or above.
[*] You can also modify an Original NAV DVD to add speed cameras and also Audio Alerts.
[*] Latest Nav DVD can be purchased in a swap scheme from your dealer for £99, latest is 2010-1, as of Dec 09.
[*] How to set the clock is here

//M Specific
[*] The “features” of the CDV are very noticeable on the /M and will often result in Kangarooing in 1st/2nd changes.
[*] Z4Ms all have a noticeable VANOS noise at about 3-4k RPM. This is completely normal.
[*] t’s fairly common to detect issues with the alignment of an /M, resulting in often pulling to the left.
[*] Most Z4Ms will also need a new O2 sensor once in a while, it’s fairly common to have had both replaced by about 30k.
[*] As /Ms have a Limited Slip Differential, you can only disengage the DSC fully by holding the switch.
[*] Some early Z4Ms have noted grinding between 1st/2nd gear which have resulted in Warranty gearbox replacements.
[*] Here is a report of the Geometry settings for aligning a Z4MC

Useful Websites
[*] BMWFans.Info for a complete parts listing
[*] Cooper BMWParts for pricing of the above
[*] If you’re not an owner yet, Parkers has a section called ‘Facts and Figures’ where you can click to see what was a standard spec and which items were / available options.