BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - seanbmw

I've read all about the dreaded timing chain failure on 320d/520d BMWs with N47 engines manufactured between 2007 and 2011. I wanted to know if models after March 2011 (when they supposedly changed the engine) have fixed this problem?

Also on this model, is the timing chain still at the back of the engine or the front?

Thanks

Top Reply

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - PETER 4768

I'll give my verdict on these BMW timing chains, but first ...

...my background (to hopefully show that what I'm saying has something to back it up) : I used to work for a major oil and fuels company, in oil development and testing (on the Wirral) My current job is more in the oil extraction side of things, still testing, but a very different field.

There is, and never was, anything inherently 'wrong' with BMWs and timing chains. The problems have occurred due to two primary factors.

1. The long 'official' BMW service intervals. These were brought in to keep the fleet market happy, who get rid of cars at 3-4 yrs old and 60k miles. If only 2 or 3 oil changes in that time, then maintenance costs are greatly reduced. However, oil that has done 15-18k miles has suffered a horrible amount of degradation, and its lubricating properties are pretty much shot. Fast forward 4 or 5 years, and those timing chains end up getting stretched, jump a link, and the engine is goosed.

2. People not cooling the turbo (especially on diesels). After a long run at speed (motorway, for example), you pull into the service station and switch off the engine immediately. The oil that is around the bearings of the turbocharger stops moving, and sits there. The turbo is at a high temperature, and that oil basically gets cooked. Some of it turns to solid carbon. Eventually, those lumps of carbon dislodge and move around the engine. You HOPE that they end up in the sump. However, they'll also tend to get stuck in any really small pipe/mozzle - like the ones that spray the oil onto the timing chain to keep it lubricated, for example. Those block up, no oil on timing chain, engine goosed again.

Basically, to greatly avoid these problems : change oil/filter at most every 10,000 miles, and idle the engine for a minute or 2 after a long run at speed, or if you've been towing.

Absolutely spot on but im yet to see the N47D20A engine fail in a car that doesnt have suspect service history, this in my opinion being the true cause of so many failures. Lease companies hire cars out on maintaince free contracts of normally 3 years 36k miles, you get the car serviced every year and hand it back at the end of the period with the mileage at no more than 36k or you pay a fee for every mile you go over. Unscrupous individuals or companies do as many miles as they like and just clock the vehicle prior to the hand back with a fully stamped service book. Invariably joe punter buys what he thinks is a low mileage car with provenance but in reality its far from it. Why do you think so many companies are still offering mileage adjustment, it can only be of use for cars of under 3 year old as all mot mileage is now recorded.

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BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - RobJP

I'll give my verdict on these BMW timing chains, but first ...

...my background (to hopefully show that what I'm saying has something to back it up) : I used to work for a major oil and fuels company, in oil development and testing (on the Wirral) My current job is more in the oil extraction side of things, still testing, but a very different field.

There is, and never was, anything inherently 'wrong' with BMWs and timing chains. The problems have occurred due to two primary factors.

1. The long 'official' BMW service intervals. These were brought in to keep the fleet market happy, who get rid of cars at 3-4 yrs old and 60k miles. If only 2 or 3 oil changes in that time, then maintenance costs are greatly reduced. However, oil that has done 15-18k miles has suffered a horrible amount of degradation, and its lubricating properties are pretty much shot. Fast forward 4 or 5 years, and those timing chains end up getting stretched, jump a link, and the engine is goosed.

2. People not cooling the turbo (especially on diesels). After a long run at speed (motorway, for example), you pull into the service station and switch off the engine immediately. The oil that is around the bearings of the turbocharger stops moving, and sits there. The turbo is at a high temperature, and that oil basically gets cooked. Some of it turns to solid carbon. Eventually, those lumps of carbon dislodge and move around the engine. You HOPE that they end up in the sump. However, they'll also tend to get stuck in any really small pipe/mozzle - like the ones that spray the oil onto the timing chain to keep it lubricated, for example. Those block up, no oil on timing chain, engine goosed again.

Basically, to greatly avoid these problems : change oil/filter at most every 10,000 miles, and idle the engine for a minute or 2 after a long run at speed, or if you've been towing.

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - seanbmw

Thanks for the very informative message. I have heard that about the long service intervals in a few places, but is the problem not accelerated by the sprockets being too sharp which guide the chain?

I asked Honest John and it was said that the timing chain is still at the back of the engine and he has not heard of any failures after 2011.

Even with the new 2011 design and a service (inc oil change) every 10k miles, will I still need to eventually replace the timing chain after 100k miles or so?

If so, is this still going to be a £2000 - £8000 job as it's still an "engine out" job?

Thanks

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - RobJP

Not hearing of any failures since 2011 cars just means that those cars (which are only 3 years old now) haven't reached that stage/mileage ... yet ! Or any that have have been covered by BMW.

Serviced right, I see no reason why those timing chains won't last 200k plus. One of our managers does 80k a year (is up to Aberdeen every week), is running a 2012 (newshape) 520d SE, has it serviced every 10k miles. It's on 145k so far, and still running perfectly in every regard.

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - Railroad.
I'm glad someone else has enough sense to understand that extended oil changes are sales pitch, and should be taken with a huge pinch of salt. Modern engines aren't really much different from those 100 years ago, and good lubrication is as essential now as it was then. I can understand that cars can go 30,000 miles or so between oil changes if they are used for long continuous journeys, and those miles are clocked up in a short space of time. For the rest of us though we should treat our car to an oil and filter change at least once every twelve months otherwise we really are asking for trouble.

Edited by Railroad. on 17/07/2014 at 15:30

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - seanbmw

That's very true about them most likely being covered under warranty. But I do know that lots of 3 year old BMWs will have exceeded 100k miles by now so would've expected to hear something if there was anything wrong with those models also.

Just looking for some evidence that it has been fixed or at the very least improved in the 2011 onwards models.

Thanks again for this information. Definitely gives me some hope that they aren't all just going to fail.

When you say "serviced right", I assume you just mean changing the oil and filters every 10k miles (or once a year if that comes sooner)?

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - RobJP

Yes. Some people go further (6k) but if you're doing 10k/annual oil changes, whichever comes first, then you won't go far wrong.

BMW 3 Series (2011), BMW 5 Series (2011) - N47 engines after 03/11 - timing chain problem? - PETER 4768

I'll give my verdict on these BMW timing chains, but first ...

...my background (to hopefully show that what I'm saying has something to back it up) : I used to work for a major oil and fuels company, in oil development and testing (on the Wirral) My current job is more in the oil extraction side of things, still testing, but a very different field.

There is, and never was, anything inherently 'wrong' with BMWs and timing chains. The problems have occurred due to two primary factors.

1. The long 'official' BMW service intervals. These were brought in to keep the fleet market happy, who get rid of cars at 3-4 yrs old and 60k miles. If only 2 or 3 oil changes in that time, then maintenance costs are greatly reduced. However, oil that has done 15-18k miles has suffered a horrible amount of degradation, and its lubricating properties are pretty much shot. Fast forward 4 or 5 years, and those timing chains end up getting stretched, jump a link, and the engine is goosed.

2. People not cooling the turbo (especially on diesels). After a long run at speed (motorway, for example), you pull into the service station and switch off the engine immediately. The oil that is around the bearings of the turbocharger stops moving, and sits there. The turbo is at a high temperature, and that oil basically gets cooked. Some of it turns to solid carbon. Eventually, those lumps of carbon dislodge and move around the engine. You HOPE that they end up in the sump. However, they'll also tend to get stuck in any really small pipe/mozzle - like the ones that spray the oil onto the timing chain to keep it lubricated, for example. Those block up, no oil on timing chain, engine goosed again.

Basically, to greatly avoid these problems : change oil/filter at most every 10,000 miles, and idle the engine for a minute or 2 after a long run at speed, or if you've been towing.

Absolutely spot on but im yet to see the N47D20A engine fail in a car that doesnt have suspect service history, this in my opinion being the true cause of so many failures. Lease companies hire cars out on maintaince free contracts of normally 3 years 36k miles, you get the car serviced every year and hand it back at the end of the period with the mileage at no more than 36k or you pay a fee for every mile you go over. Unscrupous individuals or companies do as many miles as they like and just clock the vehicle prior to the hand back with a fully stamped service book. Invariably joe punter buys what he thinks is a low mileage car with provenance but in reality its far from it. Why do you think so many companies are still offering mileage adjustment, it can only be of use for cars of under 3 year old as all mot mileage is now recorded.

 

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