BMW Z4 E85 and E86 (2002 to 2008)

The E85 Z4 replaced the Z3 in 2002 and, like its predecessor, was built exclusively at BMW's Spartanburg plant in South Carolina. It was a far more modern and grown-up car: stiffer, roomier and wrapped in sharply creased styling that divided opinion at the time but has aged well. The roadster was joined in 2006 by the E86 coupe, a fixed-roof version with a distinctive double-bubble roof and a hatchback tailgate, sold only with six-cylinder engines.

Most cars use BMW's smooth straight-six engines, first the M54 family and from 2006 the newer N52. A four-cylinder 2.0 arrived in 2005. At the top sat the M Roadster and M Coupe, using the high-revving 3.2-litre S54 from the E46 M3, with hydraulic power steering, bigger brakes and conventional tyres. Standard cars use electric power steering and run-flat tyres, which some drivers find numb and firm.

Reputation is generally good. The bodyshell resists rust far better than older BMWs, and the engines are strong if serviced. The weak points are well known: water getting into the hood motor in the boot, snapped rear springs, cooling system parts and some electrical modules. Buying guides consistently recommend a six-cylinder car with a full service history and steer buyers away from the SMG automated manual.

• Production: 2002 to 2008 at Spartanburg, USA. BMW Group Classic gives September 2002 to November 2008; other references give July 2002 to December 2008. UK sales began in 2003.
• Body styles: two-seat roadster (E85, power fabric hood) from 2002; two-seat coupe (E86) from 2006.
• M54 six-cylinder engines (2003 to 2006): 2.2i (170bhp), 2.5i (around 192 to 193bhp), 3.0i (231bhp).
• N46 four-cylinder (from 2005): 2.0i (150bhp).
• N52 six-cylinder engines (from 2006): 2.5i (about 174bhp in later form), 2.5si (215bhp), 3.0si (quoted variously as 258, 261 and 265bhp depending on source and units).
• M Roadster and M Coupe: S54 3.2-litre six, 338bhp.
• Gearboxes: five-speed and six-speed manuals; five-speed automatic on M54 cars and six-speed automatic on N52 cars; six-speed SMG automated manual optional on some M54 sixes.
• Production numbers: none of the sources opened gave reliable totals, so none are quoted here.

• 2002 to 2003: roadster launched with 2.2, 2.5 and 3.0 M54 engines.
• 2005: 2.0 four-cylinder with six-speed manual effectively replaces the 2.2.
• 2006: facelift. N52 engines replace the M54 sixes in the roadster as 2.5i, 2.5si and 3.0si. E86 coupe launched as 3.0si and M Coupe, and the M Roadster is on UK sale. BMW Group Classic lists M production dates that do not match this exactly, so dates for the M cars should be checked against the individual car.
• 2008: production ends. The roadster is succeeded by the E89 with a folding metal roof; the coupe had no direct successor.
• UK trims included base, SE and Sport, plus Edition Sport and Edition Exclusive specials. A small number of right-hand-drive Alpina Roadster S models also reached the UK.

Bodywork and structure

• Rust is uncommon. Corrosion usually points to poorly repaired accident damage, so check panel gaps, paint matching and overspray, and run a history check.
• The aluminium bonnet dents easily from stones. Front bumpers collect scrapes.
• Coupes can show cosmetic rust along the tailgate seams. Look underneath for corrosion on cars that have lived near the coast.
• Exhaust hanger welds can fatigue and snap, causing rattles.

Engine

• Electric water pumps on N46 and N52 engines can fail without warning, often around 100,000 miles, causing overheating. Ask when it was replaced.
• A rattle and loss of power can mean a failed DISA intake valve.
• Cam sensor failure causes hesitation and difficult hot starting.
• M54 sixes, particularly the 2.2, can use oil. Look for leaks from the oil filter housing, cam cover and the crankcase ventilation system; smoke may point to a split breather valve.
• N46 2.0: timing chain and plastic guide wear shows as a slap on start up. Oil leaks and Valvetronic or VANOS faults are also reported. Sources suggest it is the weakest engine and should only be bought with flawless history.
• N52: oil leaks, belt tensioner wear and, more rarely, wear in the inlet camshaft bearing that triggers VANOS fault codes.
• At a viewing, a simple code reader plugged into the diagnostic socket can reveal stored faults even if the car cannot be driven.

Gearbox and drivetrain

• Manual gearboxes are strong. The ZF six-speed on 3.0 manual cars can feel stiff when detent springs stick.
• SMG is widely regarded as the one to avoid; pump failures are known and parts are harder to find.
• The N52 automatic's plastic sump is worth replacing at high mileage.
• High-mileage differentials and driveshafts can clunk.

Suspension, steering and brakes

• Rear coil springs often snap. Look at the rear stance for sagging and look for broken coils behind the wheels.
• Front control arms, ball joints and rear trailing arm bushes wear, giving vague steering or a wandering rear.
• Electric power steering faults can produce heavy steering and a warning light. Racks and columns are costly new.
• Rear brake pipes rust. Check the handbrake; more than about ten clicks suggests stretched cables or worn shoes.
• Run-flat tyres have no spare wheel; many owners have switched to conventional tyres with a sealant kit.

Electrics and interior

• Roadster hood motor and pump sit in the boot floor. Blocked hood drains or leaking boot seals let water in and drown it. Lift the boot floor and look for damp or corrosion, and operate the roof fully. Unlike the Z3, there is no manual way to raise or lower it if the system fails.
• The GM5 body module behind the glovebox controls windows, wipers and locking; a weak battery can mimic its faults.
• Window regulators wear, door mirror glass can drop off, and headlamps go hazy. Faulty xenon self-levelling is an MoT failure.
• Rattles and squeaks from trim are common.

Identity and paperwork

• M Roadsters and M Coupes have the S54 engine, hydraulic steering, larger brakes shared with the E46 M3 CSL and conventional tyres rather than run-flats. Check VIN and engine number with a dealer or club decoder, as body kits and badges on lesser cars are common.
• Confirm whether the car is a 2.5i, 2.5si or 3.0si, since badging alone can mislead.

Parts supply is strong. Many components are shared with the E46 and E90 3 Series, and independent BMW specialists are common throughout the UK. Hood motor relocation, spring replacement and cooling upgrades are well understood jobs. Some items, such as electric steering racks and xenon headlamps, are expensive new, so used and reconditioned parts are widely used.

The BMW Car Club of Great Britain (bmwcarclubgb.uk (opens in a new tab)) has a Z register. There are also busy independent online forums for Z4 roadster and coupe owners.

• Has the hood motor ever been replaced or relocated, and are the drains kept clear?
• When were the water pump, rear springs and suspension bushes last replaced?
• Is the gearbox manual, automatic or SMG, and are there any stored fault codes?
• Has the car run on run-flat or conventional tyres, and is a repair kit supplied?
• For an M model, can the build details and engine number be confirmed as genuine?