BMW N47: A Guide to the Engine, Weak Points, and Maintenance
Quick Summary
The BMW N47 is a four-cylinder diesel fitted to the E60 from 2007 through 2015. It came as a 1.6L (N47D16) or a 2.0L (N47D20), with outputs from 95 to 218 hp. The main weak point is the timing chain at the rear of the engine—pre-2011 cars are prone to snapping it. With proper care the engine is good for 186,000–249,000 miles, but it demands shortened oil change intervals.
The Problem
You get in, hit the starter—and hear a rattle from the transmission side. The engine runs rough when cold, and a camshaft timing correlation fault lights up on the dash. Those are the signs of a stretched timing chain, the most expensive failure the N47 knows. Because the chain sits at the rear, on the flywheel side, replacement means removing the transmission, and the bill runs steep.
Symptoms
- Noise from the transmission side (especially when cold)
- Camshaft timing correlation faults
- Rough, uneven engine running
- High oil consumption
- Power loss, smoke, and increased fuel consumption
Causes
The timing chain is the N47’s Achilles’ heel. Until 2011 BMW used a chain prone to stretching and snapping. After 2011 the chain and the timing chain tensioner were revised, but the problem never fully went away. A chain that lets go at speed means an engine rebuild or a replacement engine.
Intake swirl flaps gum up with carbon, stop moving freely, and can break off. A detached flap ends up in the cylinder and damages the pistons and cylinder head.
The EGR valve cokes up—that causes rough running and power loss. Piezo injectors are sensitive to fuel quality and fail over time.
High oil consumption traces back to worn piston rings. Up to 1 quart per 620 miles isn’t critical for a diesel, but the level needs regular checks.
The Fix
Timing Chain Replacement
| Item | Detail |
|---|---|
| Timing chain replacement | significant cost |
| Engine replacement | very significant cost |
| Labor time | 10–12 hours |
| Preventive replacement | every 93,000–124,000 miles |
If the chain has never been done, budget for preventive replacement now. It’s cheaper than an engine rebuild after the chain snaps.
Oil and Service Intervals
BMW’s official schedule allows 19,000 miles, and that’s too long for the N47. Change the oil every 9,000 miles—it cuts wear on both the chain and the injectors. Use oil that meets the Longlife-04 specification; it protects the diesel particulate filter (DPF).
Preventive Maintenance
- Delete or replace the intake swirl flaps with a more robust design—this removes the risk of a flap breaking off.
- Check the crankcase breather—a clogged one raises crankcase pressure and speeds up seal wear.
- Change the coolant every 4 years. Overheating is hard on the aluminum block—the cylinder head can warp.
- Run computer diagnostics regularly—it catches injector, EGR, and chain problems at an early stage.
Pre-Purchase Checklist
- Ask for the timing chain replacement history—if it’s never been done, plan on preventive replacement
- Listen to a cold start after the car sat overnight—knocking and rattling point to a stretched chain
- Inspect the injectors—carbon buildup around them means they’re not sealing
- Check the oil and coolant levels—traces of one fluid in the other call for a closer diagnosis
- Assess the dual-mass flywheel—vibration and clunking when you stab the throttle point to wear
Twin-Turbo Versions (123d)
The twin-turbo N47 makes up to 218 hp. Two turbochargers mean higher thermal loads, so it needs upgraded cooling and more frequent service:
- Oil changes every 6,000–7,000 miles
- Oil with a high-temperature rating
- Regular checks of the intercooler and its hoses
- An auxiliary oil cooler for hard use
Bottom Line
The N47 is a mixed bag: properly maintained, it’s reliable and frugal, but it needs more frequent servicing than its M47 predecessor. The essentials—shorten the oil change interval to 9,000 miles, replace the timing chain and intake swirl flaps preventively. Do that, and the N47 is a solid choice.