BMW 116i (E87) N45B16: Quick Breakdown of Weak Spots and Maintenance
Summary
The BMW 116i in E87 form is a compact rear-wheel-drive car with the 1.6-liter N45B16 gasoline engine, rated at 116 hp (85 kW), built from September 2004 through June 2011. The engine needs regular oil level checks and is prone to ignition coil and timing chain problems. Overheating is its main enemy. This guide is for owners and buyers who want to know what to watch for in daily use and at an inspection.
The Problem
You get in the car, turn the key — and the engine runs rough, the revs wander, and the throttle doesn’t pull like it used to. Or a metallic rattle comes from the front of the engine on a cold start. For a BMW 116i (E87) owner with the N45B16, these symptoms aren’t rare. The engine has several weak spots, and without knowing them it’s easy to end up with a costly repair. Here’s what’s happening, why it happens, and how to deal with it.
Symptoms
- Misfires, fluctuating revs, loss of power
- Metallic rattle from the front of the engine when cold
- Rough running and increased fuel consumption
- Unstable idle
- Illuminated Check Engine light
- Oil drips under the car
Causes
The N45B16 is a 1.6-liter naturally aspirated engine with VANOS variable valve timing. It tends to use a small amount of oil, so check the level regularly and change the oil every 6,000–9,000 miles. If the oil loss goes unnoticed, wear on the piston assembly accelerates.
Ignition coils are a known sore point: when they fail, you get misfires and power loss. The timing chain has a limited service life — once it stretches, it rattles on cold starts, and in a neglected case it can jump a tooth. Dirty injectors upset mixture formation, and a vacuum leak through cracked intake boots destabilizes running and triggers oxygen sensor codes.
The Fix
Scheduled maintenance. Change the oil every 6,000–9,000 miles using only manufacturer-approved grades. Check the level at every fill-up — the engine is prone to oil consumption. Replace the spark plugs every 25,000–37,000 miles; swap coils as misfires appear.
Cooling system checks. Overheating is the N45B16‘s main enemy. Inspect the hoses, radiator, and expansion tank for leaks regularly. The coolant level should sit between the MIN and MAX marks on a cold engine. Check the tension and condition of the alternator drive belt — a loose or cracked belt leads to serious failures.
Timing chain diagnostics. If a metallic rattle shows up on cold starts, check the chain tension. Replace the chain together with the VANOS units, strictly following the torque specs and timing marks. A compression test and a gauge check of oil pressure will help you assess the condition of the piston assembly and valves. For the N45T variant (the turbo version), these procedures have their own specifics.
Fuel system and intake. Remove, clean, and test dirty injectors. Inspect the intake boots for cracks — a vacuum leak causes unstable running and oxygen sensor codes. Failing oxygen sensors drive up fuel consumption; a clogged catalytic converter means power loss and overheating.
Pre-Purchase Checklist
- Start the engine and listen: a knock or rattle from the front is the sign of a stretched chain
- Check the idle: stumbling can point to a chain that has jumped
- Inspect the oil pan from below for leaks; check the oil level and condition
- Check the air filter: it should be clean and dry
- If the Check Engine light is on, pull the fault codes
Bottom Line
The N45B16 is a reliable naturally aspirated engine if you watch the oil level, don’t let it overheat, and replace plugs, coils, and the timing chain on time. The main risks are oil consumption, ignition coils, and the chain. Before buying, get a proper pre-purchase inspection: listen to the engine cold and scan for codes. Keep up with scheduled maintenance and you’ll get a long engine life without a rebuild.