BMW N20 Engine Timing Chain Service

The venerable 4 cylinder N20 engine was available as the base powerplant in almost every BMW model offered from 2011 to 2018. Millions of these engines exist and after 15 years of observing them in the wild we see their potential shortcomings when it comes to their long term health. One of the leading reliability concerns include their timing chain or oil pump chain system, where they are known to suffer premature wear or failure resulting in catastrophic engine loss. This concern has even been the subject of class action lawsuits and many vehicles being totaled due to prohibitive engine replacement costs.

While we feel there may be several root causes ranging from design and material concerns, to BMW’s very long 13,000 mile oil service intervals, we also see damage stemming from deferred maintenance or neglect resulting in subsequent owners getting stuck with expensive repairs or the loss of their vehicle. Luckily, when performed as a preventative measure, our Signature Service for the restoration of this timing chain system can breathe new life into your BMW’s engine. This is an especially important service if retaining your N20 powered BMW towards 200k miles is desired.

The timing chain of a modern internal combustion engine is part of a critical system that maintains the synchronous rotation and “timing” of the camshafts to the crankshaft. The failure of the engine’s timing chain will result in loss of precise rotation within the engine’s critical components, similar to how a chain failure on a bicycle might result in a catastrophic breakdown. Since the camshafts open and close the intake and exhaust valves, loss of their precise timing in relation to the piston movement results in bent valves, broken pistons, or worse, and is why damage is usually so severe that engine replacement is prescribed.

Do I Need This Service?

We have found these components worn to varying degrees across all N20’s examined. Most are worn to a discernible amount yet we might not yet advise action. Sometimes, wear is present to the oil pump chain which is concealed in the oil sump and not able to be inspected without disassembly. However, occasionally we receive some vehicles with audible noise which we immediately notice. While many may not pay a second thought to how their engine sounds, our experienced technicians and trained ears can identify the slightest abnormality. An irregular noise is caused by slack in one of the chains and looseness within the system. Sometimes, the plastic sliding rails have broken. These are the most concerning and require immediate attention because the slack may allow the chain to skip a tooth at any time which equates to engine loss. Other times on examination we find measurable wear to a lesser degree and simply recommend scheduling preventative service as soon as possible.

At every service opportunity, getting your car in front of our qualified and experienced technicians is key to helping identify shortcomings in your engine’s health as mileage accrues.

The timing chain and their guide rails are a critical support component and deeply contained within the engine. Access to these parts require significant disassembly of both the top of the engine as well as the bottom end. The oil pump chains are only available for service with removal of the front suspension subframe and oil pan. Some shops may cut corners here to reduce the quoted job price but beware of the long term repercussions!

Our signature service considers the mandatory components required to complete this repair, always including a new set of chain and sliding rail (guide) parts. Furthermore, it will always include a new valve cover assembly (top end) and oil pan gasket and associated sealings and gaskets. X-drive (awd) vehicles will require a more extensive parts and labor scope due to the additional complexity of the front drivetrain parts.

Addition components considered an “add-on” might be replacement oil pump chain system, engine mounts, water pump and thermostat, solenoids or Valvetronic sensor, or other parts prone to wear or failure which are readily accessible during the repair scope . These parts are typically added at part price only and might not add labor cost; a valuable consideration to add long term reliability at minimal cost “while we’re in there”.

As the condition of each vehicle varies, we recommend that we assess the vehicle and provide a customized estimate tailored to your car’s needs. No two jobs will be the same.

Beware of the lowest bidder. As such an intensive engine repair, costs may seem high, and low bids can be appealing. There are numerous shortcuts that a shop will consider during this job. Discipline and attention to detail is critical to this task’s long term success. Choose the shop with the best reputation and experience with this service. Only one that offers full documentation using OE parts and practices should be considered.