2019-2024 · 3.0L B58 turbocharged inline-6 (340 hp / 382 hp US)
Premium roadster with Toyota Supra DNA and BMW's most reliable modern turbo six-cylinder. The B58 engine is exceptionally robust, but watch for coolant system components (expansion tank, water pump) and carbon buildup from direct injection. Convertible roof hydraulics can fail expensively. No manual transmission option, but the 8-speed automatic is quick and smooth. Shares platform with Toyota GR Supra. Check all recalls completed, particularly the critical engine starter relay fire risk recall affecting 2019-2022 models.
Hydraulic system seizes or pump fails, roof gets stuck open or closed · more· less
The G29 uses a soft-top with hydraulic actuation. Common faults include automatic front catch stuck (won't release or won't lock), boot lid won't open, roof stops halfway, microswitch failure, and Hall sensor position failure. Water damage to the hydraulic pump is a known issue across Z4 generations when rear drains become blocked. Professional repair typically costs €1,400-2,500 due to 8-hour labor requirement to access components. Correct diagnostic equipment (Autologic or BMW ICOM) is crucial - generic tools don't communicate properly with the roof control system.
B58 coolant expansion tank / water pump failure€700 - €1,200
Plastic tank cracks, water pump fails at 75,000-100,000 km · more· less
The B58 electric water pump typically fails between 75,000-100,000 km, though failures as early as 5,000 km have been reported. The plastic coolant expansion tank develops stress cracks from thermal cycles, and the small-diameter vent hose connecting the oil filter housing to expansion tank becomes brittle after 3-5 years. Coolant loss affects 35% of B58 owners according to a 2016 Bimmerpost poll. Professional replacement of water pump + thermostat + vent hose costs €700-1,200. The parts are integrated, so proactive replacement of the entire cooling system at 80,000+ km is recommended.
The B58 PCV (crankcase ventilation) valve is integrated into the valve cover. The rubber diaphragm ruptures or tears due to constant negative pressure and heat cycles, causing blue/white exhaust smoke and loud whistling. BMW stated this affected many 2017-2021 models and extended warranty to 15 years/150,000 miles with reimbursement provision. On early B58s the diaphragm can be replaced separately (€300-600), but on B58TU1 engines the entire valve cover must be replaced (€600-1,800 at dealer, including 26 new aluminum bolts and gaskets). DIY PCV diaphragm kits available for €100-150.
Valve cover gasket leak€600 - €1,800
Rubber gasket degrades at 70,000-100,000 km causing oil leaks · more· less
The valve cover gasket commonly fails between 70,000-100,000 km as rubber material degrades from heat cycles. Oil leaks onto hot components (cylinder head, exhaust) causing burning oil smell and potentially contaminating spark plug tubes leading to misfires. The valve cover itself is plastic and becomes brittle at higher mileage, so dealers typically replace the entire cover (€600 parts + €600-1,200 labor for 3-4 hours). Independent specialists charge less. Aftermarket Febi valve covers cost €275-350 with gaskets included.
Carbon buildup on intake valves€400 - €1,000
Direct injection causes carbon deposits, needs walnut blasting every 50,000-60,000 km · more· less
All direct injection engines suffer carbon buildup because fuel doesn't wash over intake valves. The B58 requires walnut blasting every 40,000-60,000 km during normal driving to maintain performance. Symptoms include rough idle, misfires, reduced throttle response, and poor fuel economy. Professional walnut blasting costs €400-725 including new intake manifold gaskets (dealer charges €700-1,000). DIY kits available but require intake manifold removal. This is scheduled maintenance, not a defect, but ignoring it causes performance degradation.
Water causes corrosion leading to short circuit and fire risk · more· less
BMW recalled 196,355 vehicles including 2019-2022 Z4 models due to Valeo-manufactured starter relay corrosion from moisture exposure. Corrosion can prevent starter operation and in worst cases cause short circuit leading to fire. Owners advised to park outside and away from structures until repair completed. BMW dealers replace engine starter free of charge. This is a critical safety recall - verify completion with VIN check before purchase.
Steering tie rod failure (2019 models)€0 (recall)
Tie rod can fracture in kink groove area affecting steering control · more· less
BMW recalled 2019 Z4 sDrive30i models (produced Oct 30, 2018 - July 5, 2019) due to steering tie rod damage risk. In high temperatures and rough road surfaces, the tie rod can become damaged and break in the kink groove area, affecting vehicle handling and increasing crash risk. Recall affects 3,800 vehicles (2,779 US, 1,018 Canada). BMW dealers replace both steering tie rods free of charge. Modified design with increased kink groove radius implemented in production from 2019 onward.
Turbo wastegate actuator sticking€500 - €2,500
Carbon buildup from gentle driving causes actuator to stick, triggering limp mode · more· less
The electronic wastegate actuator can stick if driven too gently or only for short trips, as carbon builds up. Symptoms include EPC warning light, drivetrain malfunction code, and limp mode with severe power loss. The actuator is bolted to the hot turbo and can get "cooked" (capacitors fail, oil ingress). BMW dealers recommend replacing entire turbocharger (€1,200-2,500), but specialists can replace actuator alone (€500-600). Regular spirited driving and premium fuel help prevent this. B58 has lower failure rate than problematic N20/N55 engines.
Reliable powertrain, but premium maintenance costs
The B58 engine is BMW's most reliable modern turbocharged six-cylinder, significantly improved over the problematic N54/N55. Most issues are preventable with proper maintenance (regular oil changes, walnut blasting, cooling system refresh at 80,000 km). The convertible roof hydraulics are the main concern unique to the Z4. Verify all recalls completed, especially the critical starter relay fire risk recall.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete BMW dealer or authorized specialist records essential. Verify oil changes every 10,000 km maximum (enthusiasts recommend 8,000 km).
Cold start
Must start engine completely cold. Listen for unusual sounds, check for blue/white smoke (PCV failure).
Test drive
Minimum 30 minutes including highway speeds to get transmission and roof system up to temperature.
Specific for this vehicle
Operate convertible roof fully (up and down)
Test complete cycle multiple times. Listen for abnormal hydraulic pump noise. Check automatic front latch operation. Verify roof doesn't stop halfway. Inspect rear drain holes for blockage.
Check coolant level and condition
Low coolant indicates expansion tank crack or water pump leak. Inspect expansion tank for stress cracks. Check small-diameter vent hose from oil filter housing for brittleness.
Inspect valve cover for oil leaks
Look for oil residue around perimeter and spark plug openings. Smell for burning oil during test drive (oil on exhaust manifold).
Cold start smoke test
Watch exhaust on cold start for blue or white smoke (PCV diaphragm failure). Listen for loud whistling sound from engine bay.
Verify all recalls completed
Critical: Engine starter relay recall (2019-2022). Steering tie rod recall (2019). Counterbalance shaft recall (2019). Fuel tank recall (2020-2021). Headlamp adjustment recall (2019-2020). Brake assist software recall (2019-2021). Use VIN check with BMW dealer.
Check for EPC/drivetrain warning lights
Drive car hard to operating temperature. Watch for EPC light or power loss (wastegate actuator). Check for boost pressure codes with diagnostic scanner.
Walnut blasting history
Ask when intake valves were last cleaned. Should be done every 40,000-60,000 km. Rough idle or hesitation indicates overdue carbon cleaning.
PCV valve / valve cover warranty extension15 years/150,000 miles
Contact BMW dealer with VIN to verify all recalls completed. The engine starter relay recall is particularly critical due to fire risk. PCV/valve cover has extended warranty with reimbursement for customer-paid repairs.
Warranty Status
Factory warranty (3 years / unlimited km Europe)Expired on all G29s
Extended warranty available (BMW Service)Up to 5 years total
PCV valve / valve cover extended warranty15 years / 150,000 miles
BMW Premium Selection warranty (used cars)Valid at BMW dealers EU-wide
All 2019-2021 Z4s are outside factory warranty. Extended warranty available through BMW dealers for 4-5 years total coverage from first registration. PCV/valve cover has special extended warranty to 15 years/150,000 miles with reimbursement provision. Check with BMW Nederland for current extended warranty pricing.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.