Another BMW burst into flames on Tuesday as it was racing down an expressway on the outskirts of Seoul, forcing the driver and passenger to abandon the car.
It was the second fire in as many days, the 11th unexplained combustion of a BMW in July alone and the 28th this year. All of the cars were models that have been put on recall.
BMW blames the exhaust gas recirculation (EGR) module in diesel engines and pledged to recall the 3, 5 and 7 Series that were manufactured between 2011 and 2016. But 100,000 owners of the affected models are still driving around the streets and highways of Korea, presenting a potential fire hazard.
The German automaker said coolant leaks in the EGR caused engine temperatures to rise, but experts doubt that the carmaker and the Ministry of Land, Infrastructure and Transport have been unable to pinpoint the exact cause of the problem.
BMW also claims that the EGR was used in models sold around the world. But the fires have been reported only in Korea and BMW has not been able to explain why.
One reason could be simple bad luck. BMW said the biggest proportion of the 5 Series were sold in Korea with 30 percent of worldwide sales, so the probability of the fires occurring here is higher. Yet no fires have been reported in the U.K. and Ireland, where sales of the 5 Series are similar to Korea's.
Could the heat wave be to blame? The number of fires rose to 11 in July alone. National Emergency Management Agency data show 653 incidents of vehicular fires occurring on average between July and August, compared to 513 in January and February.
But BMWs caught fire in winter as well, and many other places around the world saw scorching heat this summer. That leads to the suspicion that cheap parts were used in the models sold in Korea, despite BMW's protestations that the parts are the same worldwide.
Kim Pil-soo at Daelim University said, "There is a chance that another type of software was used to meet Korean emission standards."
There is always the possibility that fires have broken out in BMWs sold in other countries but were not reported. According to ABC news, around 40 incidents of combustion were reported across the U.S. over the past five years, and BMW was forced to recall 1 million of its cars including the 3 and 5 Series made from 2006 to 2011. All of the problems were traced to electrical components.
In May this year, BMW recalled 290,000 older cars of the 3 Series in the U.K. due to defects in wiring connected to the heater pan.
Ha Jong-sun at Barun Law in Seoul said, "There are suspicions that automakers are hiding the fundamental reasons and blaming already publicized components to minimize recalls."
Spontaneous combustion of cars happens more frequently than many people think. According to the NEMA, Korea sees some 5,000 such incidents every year, and 70 percent are unexplained and involve mechanical or electrical problems.
Some 3,576 fires were reported last year, an average of 10 a day. This has brought a barrage of criticism on the ministry for dragging its heels and coming to action only after the BMW fires made headlines.
A firefighter shoots water at a BMW 420d on an expressway in Incheon on Tuesday.