If you are operating a late-1990s to mid-2010s Nissan forklift, maintaining the B24BD-14 is the single most cost-effective decision you can make. Keep the LPG system clean, change the oil religiously, and never let it overheat. Do that, and this 2.4-liter iron-block warrior will outlast the chassis it sits in.

Locate the motor (usually accessible by removing the glove box or side trim on the passenger side of the center console).

While adjusting the temperature on the dash, gently tap the motor casing. If it begins to move temporarily, the internal motor brushes or gears are failing.