BMW is recalling more than a million vehicles in two recalls covering a number of models built over a six-year period, according to news reports.

The German automaker announced Friday it's recalling BMW 3-series, 5-series, X5, X3,and Z3 vehicle models, CNN Money reported.

One recall of 740,000 vehicles involves a fire risk in which part of the engine can short-circuit and melt, according to CNN Money.

A second recall involving almost 675,000 vehicles covers a valve heater that can overheat, posing a fire risk, even when the vehicle is parked and turned off.

An ABC News investigation identified 40 cases in the past five years in which parked BMWs "spontaneously burst into flames." ABC reported some of the vehicles "had been turned off for hours or even days."

Dealers are expected to begin replacing the affected parts by mid-December.