BMW replaced the N52 inline-six with the N20 turbocharged four-cylinder in the F30 chassis starting 2012. The 2013 328i is the second model year. Smooth engine, plenty of power, decent fuel economy. And a timing chain at the back of the engine that stretches.
Why the chain stretches
BMW put the timing chain on the rear of the N20 — the bell-housing end, not the accessory end most engines use. The chain runs across two sprockets, a tensioner, and a guide. The guide is plastic. The tensioner runs off oil pressure. As oil ages and the guide wears, the chain develops slack. The tensioner extends to take up the slack, runs out of travel, and the chain whips around at idle. Eventually it skips a tooth or two — and on a direct-injection turbo engine with tight piston-to-valve clearances, jumping timing means bent valves.
Symptom progression: faint rattle on cold start (the “N20 rattle”), then more pronounced rattle as it gets worse, then a check engine light for cam/crank correlation, then the engine running rough, then it doesn’t run.
The repair at a dealer: $3,500-5,500. At a competent indy with BMW experience: $2,500-3,800. The job requires removing the transmission to access the rear of the engine. It’s not a hard job — it’s an expensive job because of the labor.
What BMW did
BMW extended the warranty on N20 timing chain and chain guide to 7 years / 70,000 miles under a class action settlement (2015). Many 2013 328i cars are now well past that, but check the in-service date because some are still under coverage.
BMW also redesigned the chain guide multiple times. The 2013 has an early guide. By 2015 the guide was improved; by 2017 the N20 chain problem was effectively engineered out.
Other items on the 2013
- Oil filter housing gasket. Standard B-series ailment, leaks oil onto the alternator. $400-600.
- Valve cover gasket. Same story, $300-500.
- VANOS solenoids. Click in cold weather, replace at 80k-100k.
- Wastegate rattle on the turbo. Sounds bad, isn’t usually fatal — but if the bushings let go, you’re into a turbo. $1,500-2,500.
The 8HP70 ZF eight-speed automatic behind the N20 is excellent. No real issues if you change the fluid (despite what BMW says about “lifetime fluid”). At 60k-80k miles, do a fluid service. The 8HP is one of the best automatics ever built — don’t kill it by skipping service.
Verdict
Buy a 2013 328i only with the N20 chain documented inspected or replaced — meaning either it’s been done with paperwork, or it’s been inspected at the dealer recently with the bulletin numbers in the file, or the price reflects that you’ll need to do it.
Walk on a high-mileage 2013 with a cold-start rattle. That’s the chain on its last leg.
If the chain work has been done and the oil filter housing gasket has been addressed: this is a great-driving car that goes 200,000 miles. If it hasn’t: run the warranty math on an exclusionary BMW-specific plan, not a generic powertrain plan. Most general plans exclude the chain guide as a “wear item.”
