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BMW Z3 - Problems and Common Faults

Don't be put off a Z3 by this list. They were well built cars using quality components and access for repairs is generally good. If you look after your Z3 it shouldn't present you with any nasty surprises. It'll be cheaper to own and more fun than a Z4.

Body and Fittings

The wing mirror aluminium castings were made too thin and don't age well. The mirrors are fragile and should never be folded. It you're lucky you can repair one with liquid metal and some support. New ones are expensive. Remember that left and right hand drive mirror cores are different if tempted to buy cheap parts from abroad.

If the central locking doesn't work it may just be wear in the nylon bushings on the internal links. Bending the thick link wires will cure it.



Rusty spare wheel and plastic tray, I've seen far worse.

The spare wheel is under the car and it's plastic tray gathers road debris, this makes the wheel rust terminally. A new space saver is available cheaply on ebay from an E46, I paid 25 quid.

The spare tyre runs at a surprisingly high pressure. It's a sensible idea to remove and check it every spring.

Remember than ALL the body panels including rear quarters and outer sills bolt on. So rusty or damaged panels are very easy to change and spares are cheap.

It's common to find badly faded or damaged rear plastic windows. New ones aren't expensive and take about an hour to change as they zip in.

The boot / trunk floor can fail due to being under engineered. It's more of a problem on six cylinder cars as they put more stress on the area. Remove the tool kit plastic tray and check the four spot welds under its front lip are OK. BMW should have used thicker steel here.



Failed spot welds on an //M roadster's boot floor.

It's good practice to treat the roof with convertible top waterproofing solution at least once a year. I use the AutoGlym cleaner and restorer twin pack.

If the two roof closing handles are stiff open the roof and put a small amount of oil on the silver hook that goes to the body, you'll be amazed how much easier it is.

If the headlights seem poor it could just be oxidisation on the base of the bulb or connectors. Osram Nightbreaker bulbs will amaze you and are worth the price, same wattage and perfectly legal.

Water in the boot may be due to a failing seal on the third brake light in the boot lid. It's only about two quid, p/n 63 25 8 389 735. But you'll need a T8 torx bit to remove the outer lens (I had EVERY other size except T8 in my tool box when I did this, grrr).



Another broken mirror core.

Transmission and Drivetrain

If you buy an auto gearbox and don't know when the fluid was changed last get it done along with the filter. This should be done every 60k miles, despite BMW's official line it's not lifetime fluid. If you have any issues with an auto gearbox a fluid change is the first line of attack. Same goes for the differential and power steering.


BMW m40 engine

M43, M43TU

Four cylinder 8 valve

1.8 and 1.9

BMW m44 engine


Four cylinder 16 valve


BMW m52 engine

M52TU, M54

Six cylinder 24 valve

2.0, 2.2, 2.5, 2.8 and 3.0

BMW s50 engine

S50, S52, S54

Six cylinder 24 valve

3.0 and 3.2


BMW engines don't like the cooling system being neglected, you need a fluid change every 2 years at least.

If you buy a Z3 change the spark plugs and run some Redex / Techron through the fuel system for best results. Oil in the spark plug wells is a sign of a leaking valve cover gasket. Also inspect the serpentine belt for wear.

If you get a loud ticking noise at idle it may mean your hydraulic lifter need to be bled. This can happen if you do lots of very short journeys or let the oil run very low. Let the engine warm up then run it at 3000 rpm for three minutes whilst the car is stationary.

The dual VANOS gear on the S50B32 3.2 is a known problem and seems to fail a lot, not cheap to replace but often you just need to replace the seals. There are companies who specialise in the job and will refurbish the part by return of post.

VANOS gear can fail on other engines but it's far less common and is often a sign of poor maintenance.

Brakes, Suspension and Steering

The biggest issue with brakes by now is sticking calipers just through age. I do one or two a year on my cars as the rubber boots perish and let dirt into the piston, it's worse for me due to the winters where I live. Refurbished calipers aren't expensive or hard to fit.

Good brake pads are worth the money, look for Pagid Fast Road or EBC Red Stuff.

Change the brake fluid when you buy the car then every two years. It's hydroscopic and gathers water, not a good thing.



New lower control arms with poly bushings can cure vibration.

Vibration when braking from speed is often due to worn lower control arm bushings. Replace with a poly bushing for best effect, especially on the Z3. Failing that check the tie rods.

If laying the car up be sure to leave the handbrake off or it'll stick on.

If your steering is stiff or the pump groans when cold you need to change the power steering fluid. Sadly the reservoirs no longer have a removable filter.


Rotten rubber electric seat bushing.


The electric seat runners have rubber bushings which perish. This results in the seat moving slightly under hard braking or acceleration. You can buy after market kits for under a tenner which have mylar replacements. BMW will sell you the whole assembly for 300 quid.

Check the carpets for signs of a persistent water leak. If they stink they'll be very hard to clean properly. Z3s aren't known for leaks but it can happen.

Treat door and roof seals with a restorer such as Gummi Pfledge to ensure they stay water and wind tight.