2006 vs 2007 BMW Z4

Both years

• Power top motor drowned by the roof drains All years

  What to check: Run the power top up and down several times. A slow or stalling roof points to a tired motor. Ask whether the motor has been moved into the trunk, and clear the roof drains.

  Eight owners in four threads on a British owners' forum say the power top's motor sits where water from blocked roof drains collects and fails; several had theirs moved into the trunk, which they call the fix. An Edmunds owner review says the same, and Euro Premium Parts lists motor failures on high-mileage roadsters. One forum owner says a US car may have had a manual top as standard.

  Edmunds, owners' reports (unofficial), a seller's guide (unofficial)

• Broken rear springs and worn suspension All years

  What to check: Look at the rear springs for a broken coil and listen for knocks over bumps. Ask when the springs, dampers and front control arm bushings were last renewed.

  Three owners in one thread on a British owners' forum say the rear springs break, one that it happens on most cars over five years old, and two owners in another thread say to budget for new dampers and a suspension refresh. Euro Premium Parts says worn front control arm bushings are almost universal past 70,000 miles.

  Owners' reports (unofficial), a seller's guide (unofficial)

• Cooling system failures All years

  What to check: Ask when the water pump, thermostat and expansion tank were last renewed, look for coolant leaks and watch the temperature gauge on a long drive.

  Euro Premium Parts says the plastic thermostat housing and expansion tank crack with age, and that the N52's electric water pump can fail without warning. Seven owners in two threads on a British owners' forum name the facelift cars' water pump or a leaking expansion tank or radiator.

  Owners' reports (unofficial), a seller's guide (unofficial)

• Oil leaks from the valve cover and oil filter housing All years

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

  Five owners in three threads on a British owners' forum report leaks from the valve cover or oil filter housing gaskets as the rubber ages, and Euro Premium Parts says the oil can drip onto the exhaust.

  Owners' reports (unofficial), a seller's guide (unofficial)

• Corroded brake lines All years

  What to check: Look under the car at the rear brake pipes, where the plastic cover ends and road dirt builds up.

  Three owners in three threads on a British owners' forum report rusted brake lines, one after a leak, and one says the rear pipes rot where dirt collects at the end of their cover.

  Owners' reports (unofficial)

• Failing window regulators All years

  What to check: Run both windows up and down a few times.

  Two owners in one thread on a British owners' forum say the window regulators fail often, and Euro Premium Parts says they fail on the roadster in particular.

  Owners' reports (unofficial), a seller's guide (unofficial)

Both years

• Good find Coupe Body style

  The roadster outsold it seven to one in its first 13 months A published reference

  2,104 built for North America A published reference

  Why it is a good find: Euro Premium Parts calls the stiffer coupe a sharper driver's car and one of the more undervalued BMWs of its era. A seller's guide (unofficial)

Both years

• 22V119000 2006–2011

  The heater for the crankcase ventilation (PCV) valve may short-circuit. Dealers fit a wiring harness with a fuse for the heater. Replaces recalls 17V683000 and 19V273000. NHTSA

Both years

Engines

3.0L inline-six (2006–2008) Edmunds, a published reference, 3.0L inline-six, higher output (2006–2008) Edmunds, a published reference

Transmissions

Six-speed manual CarGurus, Edmunds, Six-speed automatic (2006–2008) Edmunds, CarGurus

Drivetrains

Rear-wheel drive Edmunds, a published reference

Body styles

Roadster Edmunds, a published reference, Coupe (2006–2008) Edmunds, a published reference

Packages

Sport Package CarGurus, Edmunds, Premium Package (2006–2008) Edmunds

Both years

• Titanium Silver Metallic 2005–2008 Edmunds
• Bright Red 2005–2008 Edmunds
• Jet Black 2005–2008 Edmunds
• Black Sapphire Metallic 2005–2008 Edmunds
• Alpine White 2005–2008 Edmunds

Both years

• Sought after: A late first-generation car 2006–2008 One source so far

  CarGurus calls late first-generation Z4s arguably the best value of the line, and says the 2006 update brought markedly more power and torque. CarGurus