The weakest link on the BMW N20 engine is a common timing chain failure, due to the guides breaking from the chain oscillations. The timing chain in most cases will rattle, oscillate wildly and in the process will break pieces off the chain guide, which will get picked up or sucked up by the oil pump which destroys the engine suddenly in the process.
The broken guide pieces may block the entire pick up screen for the engine oil pump which will seize or destroy the engine components, due to sudden lack of lubrication.
The real cause in my opinion is the ECO mode which is the default mode in the transmission after every single start of the vehicle. The chain oscillations are caused by the transmission selecting the highest possible gear with the lowest possible engine rpm to maximize the efficiency of the engine as it has been mandated by the CAFE (corporate average fuel economy in short). We had the first stage of the CAFE mandated for 2016 the next stage is proposed for 2025. The real issue at hand unfortunately is the 8 speed automatic transmission, which is programmed to provide the best possible gas mileage, which in this case is counterproductive as it will lag the engine at very low rpm to minimize fuel consumption and to maximize the efficiency of the engine.
BMW N20 engine repair because of timing chain failure.
The N20 will fire at every half turn which is 180- degrees this will (two full turns equates to 720 degrees for all the 4 cylinders to be fired) which is problematic for the single row timing chain. I can tell you from the past, the last generation 4 cylinder sold in this part of the world was the M44 (before was the M42) which had a dual row chain to prevent this issue to happen. So why did they switch to a single row timing chain system you may ask?
This is all done to maximize efficiency and to reduce the internal drag of the engine and it’s components. Back then there was no CAFE standards, manufacturers were left to build whatever they deemed fit for the purpose.
This cars are equipped with a standard transmission in Germany, so they will get a work out when they are driven to the Autobahn. In North America every one of these cars are equipped with an 8 speed automatic transmission.
How can you prevent this problem? We recommend to flip your selector to sport mode after start and don’t be afraid to give your engine a work out, after all it was built for the Autobahn. You can switch back to ECO mode to reduce the fuel consumption, when you drive on the highway at higher speed.
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This cars are meant to be driven spiritedly on the Autobahn. This doesn’t mean you have to drive it all the time as a maniac, it means keep the rpm at least medium or higher much as you can. Naturally always use proper oil and filter, at more frequent intervals, than recommended by the manufacturer. You won’t believe how many inferior oil filters we find and replace on this cars where they got some cheap inferior filters installed elsewhere.
In case you are interested in a ECO car you may want to consider an i3 or other hybrids, perhaps a hybrid BMW and or a Prius.
You also should have your vehicle serviced by a specialist, a BMW technician, so we can give you an early warning which may prevent permanent engine damage. There are tell-tale signs of this issue for a trained seasoned BMW technician, this is what we are good at. We’re working on European cars since 1976.
Any questions, how may we help? Give us a call to: 905.795.0419!