Subaru Trezia - Accumulation of oil in charge-air cooler | HELLA

The regeneration process for the particle filter can cause engine oil from the crankcase breather and/or the turbocharger to accumulate in the charge-air cooler.

Under certain operating conditions, the oil can get into the combustion chamber and cause a significant amount of smoke. In extreme cases, it can even cause engine damage.

To eliminate this problem, the engine control unit should be replaced and the charge-air cooler checked and replaced if necessary.

Although the owners of the affected models have been informed, it can be assumed for various reasons that not all vehicles have been modified.