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BMW · Convertible / Roadster · 2002–2008

BMW Z4 E85

Weaknesses, engine ratings and buying advice

2.7 / 5.0 · Based on 6 engine variants
Most Fun Engine

204–272 PS

3.0L Magnesium Benzin

Best E85 Formula: N52 Meets Soft Top

Fun to Drive!
Problem Engine

163–170 PS

2.2L 24V Benzin

5 weaknesses

Stay Away!

Generations


Engine Overview

The BMW Z4 E85 is available with 6 engine variants — from 121 to 272 hp. 1 variants had engine changes — the model year is crucial.

2.0i · Benziner· 150 PS
2005 2008
Be Careful 5 weaknesses
2.2i · Benziner· 170 PS
2003 2006
Stay Away! 5 weaknesses
2.5i · Benziner· 177–218 PS Engine Change
2003 2006
Be Careful 6 weaknesses
2005 2008
Be Careful 7 weaknesses
2006 2008
Be Careful 7 weaknesses
2.5si · Benziner· 211–218 PS
2006 2008
Be Careful 7 weaknesses
3.0i · Benziner· 231 PS
2003 2006
Be Careful 6 weaknesses
3.0si · Benziner· 265 PS
2006 2008
Be Careful 5 weaknesses

The BMW 2.0i (Benziner, 150 PS) has the N46B20 (2.0L) — rated: "Be Careful", 5 known weaknesses.

The BMW 2.2i (Benziner, 170 PS) has the M54B22 (2.2L 24V) — rated: "Stay Away!", 5 known weaknesses.

The BMW 2.5i (Benziner, 177–218 PS) comes with 3 different engines: M54B25 (2003–2006, Be Careful) und N52B25 (2005–2008, Be Careful) und N52B25 (2006–2008, Be Careful). Pay attention to the model year for the 2.5i!

The BMW 2.5si (Benziner, 211–218 PS) has the N52B25 (2.5L Magnesium) — rated: "Be Careful", 7 known weaknesses.

The BMW 3.0i (Benziner, 231 PS) has the M54B30 (3.0L 24V) — rated: "Be Careful", 6 known weaknesses.

The BMW 3.0si (Benziner, 265 PS) has the N52B30 (3.0L Magnesium) — rated: "Be Careful", 5 known weaknesses.

Vehicle Weaknesses

WeaknessCost
Soft Top: Hydraulic Pump Corrodes and Fails

The hydraulic pump for the Z4 E85 hood is mounted in a poorly protected position. Blocked drains allow water ingress; the pump corrodes and fails. Replacement is labour-intensive and expensive.

Symptoms: Roof won't open or close, pump noise without movement, roof stops halfway, smell of damp in the boot
from 80,000 km
Medium
!Water Ingress Boot / Tail Lights

Water enters through leaking tail lights or the boot vent. The expansion rivets on the tail lights become porous, seals age and allow moisture in. Can lead to short circuits and mould.

Symptoms: Damp boot floor, condensation inside tail lights, rust in the boot if left unnoticed long-term
from 80,000 km
Low
NHTSA Owner Complaints
Below Average
1,161 complaints · 2002–2008
Steering
965 ⚠ 7
Airbags
86 ⚠ 3
Electrical
52 ⚠ 1
Engine & Cooling
23
Lighting
15

Top Reported Issues

Steering (965 complaints)
Airbags (86 complaints)
Electrical (52 complaints)
Source: NHTSA (nhtsa.gov) · 2026-03

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Known Problems and Issues

A total of 41 weaknesses have been documented for the BMW Z4 E85 (2002–2008) — 34 engine-related and 7 vehicle-related. One problem engine: M54B22 (2.2L 24V). Typical issues affect Body, Suspension, Electronics, Steering.

Z4 (M54B22, 2003–2006) — Stay Away!: DISA flap valve defective, DISA valve defective, Crankcase ventilation / air leak. Power: 170 PS.

Z4 (M54B25, 2003–2006) — Be Careful: DISA valve defective, Electric thermostat defective, Crankcase ventilation — membrane tear. Power: 192 PS.

Z4 (M54B30, 2003–2006) — Be Careful: DISA valve defective, Double-VANOS O-rings worn, Piston rings coked — high oil consumption. Power: 231 PS.

Z4 (N46B20, 2005–2008) — Be Careful: Timing chain stretched / chain tensioner defective, Valvetronic eccentric shaft / actuator motor defective, VANOS solenoid valve defective. Power: 150 PS.

Z4 (N52B25, 2006–2008) — Be Careful: Electric water pump defective, Eccentric shaft sensor (Valvetronic) failure, Oil filter housing gasket leaking — oil in coolant. Power: 177 PS.

Z4 (N52B25, 2006–2008) — Be Careful: Electric water pump defective, Eccentric shaft sensor (Valvetronic) failure, Oil filter housing gasket leaking — oil in coolant. Power: 211–218 PS.

Z4 (N52B30, 2006–2008) — Be Careful: Electric water pump defective, Oil filter housing gasket — oil into coolant, Eccentric shaft sensor (Valvetronic) failure. Power: 265 PS.

What to watch out for with the BMW Z4? See the detailed listing of all engine and vehicle weaknesses in the sections above.

Frequently Asked Questions

What problems and weaknesses does the BMW Z4 E85 have? +
The BMW Z4 E85 has 34 known engine weaknesses and 7 vehicle weaknesses.
What should I look for when buying a used BMW Z4 E85? +
faq.watch_a_avoid
Which engine is recommended? +
Be careful: M54B25 (2.5L 24V), M54B30 (3.0L 24V), N46B20 (2.0L), N52B25 (2.5L Magnesium), N52B30 (3.0L Magnesium). No engine is rated 'Good Choice'. The most fun to drive is the N52B30 (3.0L Magnesium). Problem engine: M54B22 (2.2L 24V) — stay away!
Which BMW Z4 E85 engine is the most fun? +
The {code} ({displacement}) offers the most driving fun in the BMW Z4 E85 — rated: "Fun to Drive!". {description} 265 hp NA straight-six, deep bass down low, screaming crescendo above 6,000 rpm — roof down, one of the most emotional sixes of its era. Pure and direct.
Is the BMW Z4 E85 worth buying used? +
Caution is advised with the BMW Z4 E85 — 1 of 6 engine variants are rated 'Stay Away!'. The engine choice is crucial.
What horsepower variants are available for the BMW Z4 E85? +
The BMW Z4 E85 is available with engine variants from 121 to 272 hp. Petrol: M54B22 (2.2L 24V), M54B25 (2.5L 24V), M54B30 (3.0L 24V), N46B20 (2.0L), N52B25 (2.5L Magnesium), N52B30 (3.0L Magnesium).

Last updated: February 2026 · All information without guarantee