FORD and Mazda have issued an urgent warning to 70,000 owners of Ranger and BT-50 utes built since July 2016 to not drive over long grass during the summer break after 24 cars caught fire or began to "smoulder".
Grass clippings can get caught under the diesel particulate filter (DPF), which can get extremely hot and spark a fire.
The recall affects about 52,000 Ford Rangers built since July 2016 and 17,000 Mazda BT-50 utes built since 23 June 2016. Both vehicles are made on the same Thailand production line.
Added to the tally are about 7000 new Ford Rangers sitting in dealer stock and an as yet undisclosed number of BT-50s in Mazda showrooms.
Mazda says it has had 15 confirmed cases of vehicle fires. Ford says there have been "two confirmed cases of vehicles being written off" as a result of fire and "seven confirmed cases of smoke or fires which have resulted in minimal damage" since December 2016.
At first Ford thought the problem was isolated but it escalated its investigations after a "cluster" of Ranger fires in the middle of 2017.
Despite the danger, Ford and Mazda have not issued a "stop delivery" notice on cars in stock.
Ford and Mazda say the recall fix will not be ready until the new year.
Ford has issued a bulletin in the meantime to warn owners of the danger and to avoid driving in conditions that can spark a fire.
A statement from Ford Australia says: "The recall is in relation to a risk of fire due to grass or vegetation accumulation near the DPF that produces very high temperatures during regeneration mode".
The company added: "The DPF regeneration can radiate a considerable amount of heat which could create a fire risk if sufficient grass or vegetation accumulates in this area".
Owners can take their car to a Ford or Mazda dealer to have them make sure the area around the DPF is clear of debris, or owners can check it themselves.
The DPF is located in the underbody area "adjacent to the exhaust system and transmission cross member".
The Ford bulletin continues: "While the likelihood of this situation arising is low, Ford is taking precautionary action to help prevent this situation from occurring as customer safety is the company's top priority. Customers will be contacted again as parts are available to address this concern."
Ford says the Everest SUV, which shares much of its underpinnings with the Ranger and Mazda utes and is made in the same Thailand factory, is not affected.
Footnote: An earlier version of this story included only the Ford Ranger fire recall and incident figures. Mazda has since provided the number of vehicles affected and the number of incidents reported. The story has been updated to include that data.
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