2012 vs 2013 BMW Z4

Both years

• Fuel pump, injector and turbo faults on the twin-turbo cars All years

  What to check: Ask for records of the high-pressure fuel pump, injectors, coils, plugs and water pump. Scan for fault codes and look for oil leaks around the turbos.

  Two owners in one thread on a British owners' forum had the high-pressure fuel pump fail. In a second thread an owner lists the injectors, the pump, the water pump and turbo leaks as faults to expect, and in a third an owner calls the twin-turbo engine's faults far more painful than the earlier car's. CarGurus says the turbocharged cars have had timing-chain or cooling trouble.

  CarGurus, owners' reports (unofficial)

• Water in the tail lights and the trunk All years

  What to check: Look inside the tail lights for mist or water, check that every light works, and lift the trunk floor by the battery for standing water.

  Six owners in three threads on a British owners' forum report water in the tail lights, several having them replaced, and one says a failed tail light seal lets water pool under the battery.

  Owners' reports (unofficial)

• Folding hardtop faults All years

  What to check: Open and close the roof several times with the engine off, by the key and by the switch inside. Ask whether the roof relays in the trunk have been changed.

  Four owners in three threads on a British owners' forum report roof faults, from cheap microswitches and relays to a large repair bill, and one names the roof wiring as a common problem. Others say most roofs give no trouble.

  Owners' reports (unofficial)

• Cracked wheels All years

  What to check: Look at the inside of each wheel for cracks or repairs.

  Three owners in one thread on a British owners' forum had wheels of the same style crack, a fourth saying their 18-inch wheels were spared, and an owner in another thread says to check the inside of the wheels.

  Owners' reports (unofficial)

• Oil leaks from the valve cover All years

  What to check: Look for oil around the valve cover and the oil filter housing.

  Two owners in two threads on a British owners' forum name valve cover leaks and oil around the filter housing, and Edmunds' owner summary for 2011 lists valve cover gaskets among costly repairs.

  Edmunds, owners' reports (unofficial)

Both years

• 13V454000 2012–2014

  The vacuum pump that powers the brake assist may fail for lack of lubrication. Dealers modify the car to prevent it. NHTSA

• 14V627000 2012–2014

  The vacuum pump that powers the brake assist may fail for lack of lubrication. Dealers fit a locking ring in the camshaft to hold its seal disk in place. Widens recall 13V454000. NHTSA

• 24V608000 2012–2016

  A badly sealed electrical connector on the water pump can let water in and short-circuit. Dealers inspect and replace the pump and connector as needed and fit a shield. NHTSA

Both years

Engines

3.0L twin-turbo inline-six Edmunds, 3.0L twin-turbo inline-six, higher output (2011–2016) Edmunds, a published reference, 2.0L turbo four-cylinder (2012–2016) Edmunds, a published reference

Transmissions

Six-speed manual Edmunds, Seven-speed dual-clutch Edmunds, a published reference, Eight-speed automatic (2012–2016) Edmunds

Drivetrains

Rear-wheel drive Edmunds, a published reference

Body styles

Roadster Edmunds, CarGurus

Packages

Sport Package Edmunds, M Sport Package (2011–2016) Edmunds, Premium Package Edmunds, Cold Weather Package Edmunds, Premium Sound Package Edmunds, Ivory White Leather Package Edmunds, Exclusive Citrus Yellow Package Edmunds, Canyon Brown Package Edmunds, Design Pure Traction Edmunds, a published reference, Design Pure Fusion Edmunds, a published reference

Both years

• Jet Black 2011–2015 Edmunds
• Deep Sea Blue Metallic 2011–2015 Edmunds
• Crimson Red 2011–2015 Edmunds
• Melbourne Red Metallic 2011–2015 Edmunds
• Black Sapphire Metallic 2011–2015 Edmunds
• Alpine White 2011–2015 Edmunds

Both years

• Black Leatherette, 2011–2015 Edmunds
• Coral Red Leather, 2011–2015 Edmunds
• Walnut Leather, 2011–2015 Edmunds

Both years

• Avoid: A twin-turbo 35i or 35is without records or a warranty All years Less sought after

  Five owners in two threads on a British owners' forum say the twin-turbo cars have a long list of costly faults, and three of them advise against running one without a warranty. Owners' reports (unofficial)