Typically, two tall tanks were mounted to the back of the vehicle, flanking the rear door.
Periodically, the driver's assistant (lơ xe) would come around back to clear the tanks of soot using a metal pole.
This modification regained popularity in Vietnam during the subsidy period, when gasoline was in short supply.
The modified vehicles were notorious for their short range, plodding pace, and dirty operation.
Cyclists and motorcyclists, who commonly hitched onto automobiles for an easier ride, could get hurt from hot coal falling from the vehicle onto their faces.