1989 vs 1990 BMW 5 Series

Both years

• Cooling system failure All years One source so far

  What to check: Ask when the water pump, hoses, thermostat and expansion tank were last replaced, and watch the temperature gauge on a long drive.

  Euro Premium Parts calls the plastic water pump impeller, hoses and expansion tank consumables, and says a failed impeller is the leading cause of head gasket damage on the six-cylinder engines.

  A seller's guide (unofficial)

• The timing belt on early 525i cars 1989–1990 One source so far

  What to check: Ask for proof of the last timing belt change.

  Euro Premium Parts says the M20's belt must be changed on schedule, because a snapped belt means catastrophic engine damage. The later engines use a chain.

  A seller's guide (unofficial)

• Rust in the sills and floor All years One source so far

  What to check: Look at the jacking points, sills, floor pans and inner wheel arches.

  Euro Premium Parts calls sill and floor pan rust the biggest structural concern on any E34, especially where roads are salted.

  A seller's guide (unofficial)

• Worn suspension bushings All years One source so far

  What to check: On the test drive, feel for vague steering or pulling, and listen for clunks over bumps.

  Euro Premium Parts calls the front control arm and rear trailing arm bushings wear items.

  A seller's guide (unofficial)

Both years

• 90V016000 1989–1990

  The front center armrest can press on the seat belt buckle and damage its release button, so the belt may not latch. Dealers fit shorter buckles. NHTSA

• 94V066000 1989–1993

  The fuel feed hoses can harden over time and let fuel seep at the engine fitting. Dealers fit a redesigned hose and clamp. NHTSA

• 97V131000 1989–1995

  A plastic bushing on the cruise control or throttle cable can break, letting the outer cable catch on it when the accelerator is pressed. Dealers fit a spring steel clip to each cable. NHTSA

• 98V178000 1989–1995

  If a thermostat, water pump or fan belt fails and the driver misses the overheating warning, coolant pressure can damage the cooling system. Dealers fit a new design of radiator cap. NHTSA

Both years

Engines

2.5L inline-six (1989–1990) CarGurus, a published reference, 3.4L inline-six (1989–1993) CarGurus, a published reference

Transmissions

Five-speed manual CarGurus, Edmunds, a published reference, Four-speed automatic CarGurus, a published reference

Drivetrains

Rear-wheel drive CarGurus, a published reference

Body styles

Sedan Edmunds, a published reference

Both years

• Sought after: Manual sedans, V8s and the Touring All years

  CarGurus says manual sedans, V8s and Touring models are already becoming collectibles, and Euro Premium Parts says the Touring is increasingly sought after in the US. CarGurus, a seller's guide (unofficial)