What causes Subaru Turbo failure?
Just like every other engine brand that uses a turbo, lack of proper maintenance is the #1 cause of Subaru turbo failure. That’s especially true when the vehicle is driven under extreme conditions like cold starts, hard acceleration, engine braking, driving short distances, stop and go driving or long drive in hot climates. Those driving conditions, along with the high heat generated by the turbo cause rapid oil breakdown.
Subaru is no different. As the oil breaks down it uses up it anti-wear additives and thickens, reducing flow which then reduces cooling. As the cycle continues, the oil turns to sludge which clogs the banjo screen filters in the oil lines to the turbo bearings. A clogged screen dramatically reduces oil flow to the turbo.
That’s why Subaru recommends oil changes at 3,750 miles on their early turbo equipped engines. If you neglect those oil changes, you’re setting yourself up for early turbo failure.
Subaru service bulletin 02-103-07R
The problem with clogged banjo screen filters has become a big enough issue that Subaru issued a service bulletin on Oct 29, 2007 to address the issue. The bulletin recommends checking the banjo filter any time there’s a question about owner’s adherence to the 3,750 mile oil change interval OR whether the owners has checked and refilled the crankcase between oil changes.
If the banjo screen is even partially clogged, it must be cleaned or replaced.
©, 2014 Rick MuscoplatPosted on by Rick Muscoplat