Does my BMW really need a new turbo – again?
Dear Alex,
I have owned my 2015 BMW 320i from new. It has been regularly serviced, it is not driven hard and I do a lot of motorway miles. In 2021, at 95,000 miles, I had to replace the turbocharger. But two months ago, at 124,000 miles, the car went into “limp home” mode again. The dealer’s diagnosis is: “New turbo required as changing the wastegate controller on its own will only solve the issue temporarily.” The quote is £3,000. Is it credible that the turbo has failed again – and if I were to pay for it to be replaced, should I keep the car?
– MW
Dear MW,
It is credible that the turbo has failed again, but not likely. In fact, it sounds as though the wastegate actuator has failed instead.
The wastegate is a valve in the turbo that opens to allow the exhaust gases driving the turbo to be vented out. This allows the amount of boost the turbo is producing to be controlled; without a wastegate to bleed off some of the exhaust gases, the turbo could spin too quickly and be damaged.
The wastegate in your car is controlled by an electronic actuator, which determines when and how far it opens based on signals from the engine’s ECU “brain”. When this fails, the wastegate stays in the fully open position, which means no boost can be produced by the turbo, preventing it from damage.
The wastegate actuator can be adjusted or replaced – but if the problem returns, that would suggest the problem is not with the actuator but with the rod that links the actuator to the wastegate, or even the wastegate itself.
The latter is a part of the turbo and given that the former is attached within the turbo, you’d have to remove and strip down the turbo to get access. That’s why BMW recommends replacement of the turbo – it’s often the least labour-intensive solution, although clearly not the cheapest in terms of parts.
Your dealer appears to be pre-empting this by suggesting you replace the turbo now. However, I’d ask for a second opinion. I suggest you visit an independent BMW specialist and see whether they can replace or adjust the actuator – you might save quite a bit of cash.
Even if that doesn’t solve the problem, it will be cheaper for the independent to replace the turbo than a BMW main dealer.
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