BMW Z4: Best Years and Years to Avoid
The Z4 roadster spans three very different cars: the raw, hydraulic-steering E85/E86, the folding-hardtop E89, and the Toyota Supra-related G29. None is a blanket avoid, but each has a signature weak point, from the N52's electric water pump to the N54's fuel system. Buy on condition, history and a healthy roof, and the Z4 is one of the more characterful used BMWs for the money.
Quick answer
Best all-round pick: a G29 sDrive20i/30i or M40i, or a naturally aspirated E89 sDrive23i/30i (N52). Be most careful with the N54-powered 35i/35is and any N52 with an unproven electric water pump. The B58-powered G29 M40i is the standout modern choice and generally robust.
G29 (2018-present) Buy
Chassis: G29
The current Z4 was co-developed with the Toyota Supra and uses BMW's modular B-series engines. It is the most reliable Z4 to date, with faults so far limited to minor electronics. The M40i (B58) is a strong, well-proven straight six and the pick of the range.
| Best years | Any G29 sDrive20i, sDrive30i or M40i with full history is a reasonable buy. The M40i (B58) is the enthusiast choice; the four-cylinder cars are cheaper to run. |
| Years to watch | Very early 2019 cars may have had software updates; check the powered soft-top and infotainment operate correctly. |
| Engines to trust | sDrive20i (B48), sDrive30i (B48), M40i (B58) |
| Engines to check | Early cars with outstanding software updates |
Key risks
- Occasional infotainment and software glitches on early cars
- Verify the powered fabric roof operates smoothly through a full cycle
- B58 (M40i): sound engine, but confirm charge pipe and cooling are in good order
E89 (2009-2016) Mixed
Chassis: E89
The E89 swapped the old roadster's fabric roof for a folding metal hardtop, making it more of a comfortable cruiser. Quality depends on the engine: the naturally aspirated N52 sixes are the dependable choice, while the turbocharged 35i/35is (N54) and pre-2015 N20 fours need more careful vetting.
| Best years | 2009-2016 sDrive23i or sDrive30i (N52) with full history are the durable, smooth-six sweet spot. A healthy folding roof mechanism matters as much as the engine. |
| Years to watch | The sDrive35i/35is (N54) for fuel-pump, wastegate and injector issues, and the pre-2015 sDrive20i/28i (N20) for timing-chain stretch. |
| Engines to trust | sDrive23i (N52), sDrive30i (N52) |
| Engines to check | sDrive35i / 35is (N54 HPFP, wastegate, injectors), sDrive20i / 28i (N20 timing chain, pre-2015) |
Key risks
- N54 (35i/35is): high-pressure fuel pump, wastegate rattle and injector failures
- N52 electric water pump and thermostat failure at typical mileages
- N20 petrol timing-chain stretch on pre-2015 cars
- Folding hardtop mechanism and hydraulics: verify a full open-and-close cycle
E85 / E86 (2002-2008) Caution
Chassis: E85, E86
The original Z4 roadster (E85) and coupe (E86) are now cheap modern classics with hydraulic steering and real character. The M54 and later N52 sixes can be robust, but the electric water pump, VANOS and age-related wear are the risks now. The Z4 M (S54) is a separate, more specialist proposition.
| Best years | 2006-2008 facelift 2.5si/3.0si (N52) with full history are the sweet spot for smoothness, provided the electric water pump and cooling system are healthy. |
| Years to watch | Earlier M54-engined cars for VANOS and cooling wear, and the Z4 M (S54) for rod bearings and VANOS on hard-used examples. |
| Engines to trust | 2.5si / 3.0si (N52), 2.5i / 3.0i (M54, with history) |
| Engines to check | N52 cars with unproven electric water pump, Z4 M (S54 rod bearings and VANOS) |
Key risks
- N52 electric water pump and thermostat failure at typical mileages
- VANOS and cooling-system wear on high-mileage M54 and N52 cars
- S54 (Z4 M): rod bearings and VANOS units on hard-driven examples
- Age-related rust, roof-motor wear and electrical faults
The pick of the range
For most buyers, a naturally aspirated E89 sDrive23i or sDrive30i (N52) with full history and a healthy folding roof is the value sweet spot: smooth straight-six character without the turbocharged car's fuel-system risk. If budget allows, a G29 is the safest modern choice, and the M40i (B58) is the standout enthusiast pick. On any N52 car, treat evidence of a recent electric water pump as a real plus.
What to avoid, and why
Be most cautious with the E89 sDrive35i/35is (N54) unless its fuel-pump, wastegate and injector history is fully documented, and with any N52 car whose electric water pump has never been replaced. The pre-2015 N20 fours carry timing-chain risk, and the S54-powered Z4 M is a specialist buy with rod-bearing and VANOS costs. None are automatic walk-aways, but each needs the right receipts before you commit.
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Frequently asked questions
What is the most reliable BMW Z4 year?
The current G29 (2018 on) is the most reliable, using BMW's modular B48 and B58 engines and Toyota Supra co-development. Among older cars, a naturally aspirated E89 sDrive23i/30i (N52) with a healthy water pump and roof is the durable choice.
Which BMW Z4 should I avoid?
No generation is a blanket avoid. Be most careful with the E89 35i/35is (N54) without fuel-system history, any N52 car with an unproven electric water pump, and pre-2015 N20 fours lacking timing-chain evidence.
Is the BMW Z4 35i (N54) reliable?
It offers strong performance, but the N54 twin-turbo has documented high-pressure fuel pump, wastegate and injector issues. Only buy one with a clear record of that work, and budget for future fuelling and turbo repairs.
What is the difference between the E85, E89 and G29 Z4?
The E85/E86 (2002-2008) is a raw, fabric-roof roadster and coupe with hydraulic steering. The E89 (2009-2016) is a folding-metal-hardtop cruiser. The G29 (2018 on) is a modern, Supra-related roadster with a fabric roof and BMW's latest engines.
Does the BMW Z4 have water pump problems?
The N52-engined cars (E85/E86 facelift and E89 23i/30i) use an electric water pump that can fail at typical mileages, sometimes without warning. Evidence of a recent replacement is a genuine plus, and any overheating history is a reason to walk away.
Is the G29 Z4 M40i a good buy?
Yes. The M40i uses the B58 straight six, one of BMW's most dependable modern engines, in a light, rear-drive roadster. Confirm the charge pipe, cooling and powered roof are in good order and it is the standout Z4 for enthusiasts.