It hasn’t gotten nearly as much attention as the handful of early production Tata Nanos that caught fire, or the Ferrari 458 recall, also for fire safety issues, or the newly expanded investigation into Jeep Wranglers burning, and certainly not nearly the attention given the near non-event with that one crash tested Chevy Volt, but BMW appears to have a corporate wide fire problem with turbocharged models that has now resulted in recalls of BMW, MINI and Rolls-Royce vehicles. Earlier this year BMW recalled turbocharged Mini Cooper models because the circuit board controlling the auxiliary water pump used to cool down the turbocharger after the engine is shut off could develop an electrical fault due to copper migrating between circuit traces, creating a fire hazard. Now comes word that BMW is expanding a previous recall (PDF) of some 2010 BMW and Rolls-Royce models to include 2011 and 2012 models. It’s not clear if it’s the exact problem as with the Minis, though it does involve the same component, the electronic controller for the auxiliary water pump. To their credit, BMW discovered the latest problem in internal testing and there is no word on any real-world fires with consumers’ cars. The Mini recall was prompted by reports of a dozen fires, eight of them while the vehicles were parked. The latest recall (PDF) affects 2011 BMW 5 Series, and 2012 6 Series, 7 Series and X5 and X6 vehicles. Also affected are 2010-2011 Rolls-Royce Ghosts, which are built with a BMW platform and share components with the parent brand. BMW says the problem exists with 100% of the turbocharged V8 and V12 powered models in those lines. A total of about 35,000 BMW made vehicles are affected by the original and expanded BMW and Rolls-Royce recalls.
In the initial voluntary recall last October, BMW attributed the problem to an unspecified malfunction in the electronic controller. It’s possible that it’s the same problem as with the Minis.
Under certain conditions, the pump’s electronic circuit board can malfunction. The malfunction can occur as a result of certain design features in combination with high operating temperatures. Under these conditions, this can lead to a failure of the water pump. In some cases, the circuit board can overheat. In an extreme case, overheating of the circuit board can lead to smolder of the water pump. If smoldering occurs, it cannot be excluded that this may also lead to an engine compartment or vehicle fire.
In the subsequent expanded recall, BMW attributed a problem with later production vehicles to improperly made turbocharger housings, resulting in leaking coolant.
It was discovered that for the additional production, there was a manufacturing process deviation at the supplier for this limited production run of pumps, this deviation could result in cracks in the pump housing. If this were to occur, then coolant could enter and contact the pump’s circuit board.
Whether or not it’s the same exact defect affecting Minis, BMWs and Rolls-Royces, it’s clear that BMW has quality and fire safety problems involving its turbochargers’ water pumps. The recall notice sent to NHTSA from BMW identifies the faulty component supplier as Pierburg Pump Technologies GmbH.
Ronnie Schreiber edits Cars In Depth, a realistic perspective on cars & car culture and the original 3D car site. If you found this post worthwhile, you can dig deeper at Cars In Depth. If the 3D thing freaks you out, don’t worry, all the photo and video players in use at the site have mono options. Thanks for reading – RJS