BMW N47 timing chain failure

Which BMWs have the N47 engine?

Four-cylinder 2.0 diesels built from March 2007 until the B47 engine took over from 2014.

The N47 arrived in the 1 Series in March 2007 and in the 3 Series and 5 Series that September. The X3 gained it in the same month, and the X1 used it from launch. In 2014 BMW began replacing it with the B47, starting with the facelifted X3.

A 320d registered before September 2007 has the older M47 engine, with its chain at the front. If your car sits near a changeover date, a BMW dealer can confirm the engine from the registration.

What does a failing N47 chain sound like?

A rattle or ticking from the back of the engine, worst on a cold start. If the chain snaps, the engine stops.

The noise comes from the bulkhead end of the engine, not the front. BBC Watchdog also heard from owners whose engines cut out without warning, one of them at speed on the M4.

Why does the chain fail?

The chain and its tensioners wear, the chain goes slack, and nothing in the service schedule checks it.

Most engines carry their timing chain at the front. BMW put the N47’s at the back, between the engine and the gearbox. Engineers told Watchdog that a chain placed there is meant to last the life of the car, so it is never serviced.

Honest John’s owner reports point to the tensioners wearing, and to BMW’s long oil-change intervals. Its advice was fresh oil at least every 10,000 miles. As the chain slackens it rattles. With enough slack it breaks, and that commonly bends the valves.

Watchdog’s cases were cars built from 2007 to 2009. Later cars are not clear of it. Honest John recorded chain trouble on 2011 cars and on one registered in 2012.

How much does it cost to fix?

About £1,350 to £2,640 at an independent specialist before it breaks. Owners have reported £2,000 to £11,400 once it has.

The parts are not the expensive bit. Reaching them is. One independent BMW specialist prices an N47 chain from £1,395 on rear-wheel-drive cars and £1,995 on xDrive cars, as a two-day job. Another starts at £1,350. A garage that takes the engine right out charges £2,200 plus VAT and logged 33 hours on one 120d.

After a failure the figures climb. Owners in the 2013 Watchdog report paid between £2,000 and £5,000 for rebuilds. Honest John readers were quoted £6,500 for repairs to a 520d in 2015, and £11,400 by a BMW dealer for a 318d in 2016.

What has BMW said?

That it has no obligation outside the three-year warranty, but will consider goodwill case by case.

BMW gave Watchdog a statement in June 2013. It said it runs “a generous goodwill policy”. Where a lower-mileage car serviced within the BMW network had failed, it had covered most of the repair. Older cars serviced or repaired elsewhere were “typically not covered”. It added that it could not give “an indefinite guarantee against engine or component failure”. The BBC ran the report under the headline that BMW denied a manufacturing fault.

There has been no safety recall. DVSA’s records for these models list recalls for other parts, including a 2013 one for a power cable that could make the engine cut out. None is for the timing chain.

In 2015 BMW dealers carried out what Honest John called a “quality enhancement” on some cars built in 2007 and 2008: new tensioners, and a new chain where it had stretched. Owners had to ask for it. The site also recorded BMW paying half the parts on one wrecked engine in 2016 and replacing another in 2017 for about the price of a service.

Who pays for an N47 timing chain?

BMW decides goodwill case by case. The legal responsibility sits with whoever sold you the car, or the lender if it is on finance.

BMW

Has not recalled the engine for its chain. In 2013 it told the BBC it had no obligation outside its three-year warranty but would consider goodwill, mainly for lower-mileage cars serviced by BMW dealers. In 2015 it ran a free ‘quality enhancement’ on some 2007 and 2008 cars.

The dealer who sold it

Responsible in law for the car being of satisfactory quality on the day you took it, and that includes how long a part with no service interval should last. BMW’s goodwill decision does not change this.

The finance company

On hire purchase or PCP the lender supplied the car and answers for its quality as a dealer would. It has eight weeks to give a final response before you can go to the Financial Ombudsman Service.

Your warranty

These cars are long out of BMW’s three-year cover. A used-car warranty may list the chain as wear and tear or cap the payout below an engine-out job. Read the schedule, and treat a refusal as the warranty company’s answer only.

Goodwill from the manufacturer and your rights against the seller are separate. Asking for one does not give up the other.

Is the chain covered under warranty?

Not by BMW’s warranty, which ran out years ago. A used-car warranty depends on its small print.

The newest N47 is now more than ten years old, so any cover will come from a warranty sold with the car. Check two things in the schedule: whether timing chains are listed, and the limit per repair. An engine-out job can pass a low limit on labour alone.

A warranty is a separate contract. If it refuses, that tells you what the warranty company will pay. It does not decide what the dealer owes you.

Can you hand the car back?

That turns on how long ago you bought it. The Consumer Rights Act 2015 sets three windows, counted from the day you collected the car.

What has the Ombudsman decided?

Results go both ways. Mileage since purchase, and whether the chain should have lasted, decide most of them.

We found no published decision that names the N47. Three on timing chains show how the Financial Ombudsman Service reasons.

In DRN5044569, a four-year-old BMW bought at about 110,000 miles broke its chain 26 months and 25,000 miles later. The ombudsman accepted there was “some evidence” that the chain on that engine wears early, but did not uphold the complaint. The car had run too far, for too long, without trouble.

In DRN-2063056, a car bought at 47,793 miles broke down with a rattling chain five months and 4,207 miles later. The engineer instructed by the lender thought the fault was not there at delivery. The ombudsman upheld the complaint anyway, because a chain should last far longer than that, and ended the agreement.

In DRN-4039270, a Mini’s chain failed within six months. Mini UK told the Ombudsman the chain has no service life and needs no maintenance. That was enough to treat the failure as a defect, not wear, and the lender had to pay for the repair.

What should you do now?

Stop driving on a rattle, get the noise diagnosed in writing, and gather the car’s oil-change history.

1. If you can hear a rattle from the back of the engine, stop using the car. One owner drove 20 miles on it and the dealer found the engine badly damaged.
2. Have a BMW specialist confirm the source of the noise in writing, with the date and mileage. A video of a cold start helps.
3. Collect the service history, including oil changes before you owned the car. BMW’s goodwill and an engineer’s view both lean on it.
4. If it has to be repaired, ask for the old chain, guides and tensioners back, and for the invoice to list the parts fitted.
5. Work out your purchase date and mileage since, then write to the dealer, and to the finance company if there is one. If the cause is disputed, an independent inspection carries more weight than opinion.