Best/most reliable F10 5 series diesel engine?

[daveco]

The majority of sites say that the 2.0d with the auto gear box is the pick of the lot.

However the 525/530/535d are 6 cylinder engines; would these be as prone to timing chain issues/faults as the 2.0 unit in the 520d?

[VerySideways]

Definitely the 35d.

The 30d is a variable vane geometry turbo and they can get gummed up as the mileage builds, due to EGR and so on.
The 20d is noisy and obviously has a wide variety of potential problems with chains and so on - though you have to bear in mind that between the various models (120d, 320d, 520d) they have sold thousands upon thousands of these things, so don't blow the failure rate out of proportion.
The 35d is actually relatively simple with a smaller turbo and a larger turbo, but neither are variable vane.

Another advantage is that the 35d has so much torque that you don't have to use much throttle in steady speed situations, so it's not actually significantly less economical than the 30d in my experience.

[helix402]

Any 6 cylinder.

[daveco]

Thanks for the info chaps. It's a mine field of misleading information elsewhere so clarity is appreciated!

[Ken Figenus]

M series 6 cyl engines - dodgy engine killing swirlflaps.

N Series (as in my new F11 535d Friday) should have no such issues I hope! Its a more alloy evo of the M series - this engine has been around a long time and vac pipes go - other than that 200k+ in an E39 530d and 120k+ in an E61 535d another has been a good experience.

Spool down the turbos nicely, be v gentle when cold and change the oil at 14k or earlier - worked for me...

[cerb4.5lee]

I've had the 20d/30d/40d engines...I still prefer petrol!

The 35d would be my pick too and I wasn't that impressed with the 20d in my 520d, the 5 series deserves a better quality feeling engine for me.

[daveco]

Thanks for all the info!

Currently running a 320d and have been very careful with how I drive it, letting it idle before switching off, not going above 2k rpm for first 15 min etc. Engine still feels 'delicate' compared to the petrol BMWs I've had before so hopefully the 6 cylinder dervs feel at little more robust and less rickety.

[balfron100]

I've had both 2 & 3L diesel engines in the 5 series F10, much prefer the 3.0L engine. Smoother and more responsive without the rattle from the N47 2.0L.

[bearman68]

The N47 is a tremendous engine for what it is though. For a 4 cylinder diesel, it's fast and smooth, and revs well.
Downsides are timing chain, and the swirl flaps. (Done both)

[Patrick Bateman]

Having driven a 640d, you'd be absolutely mad to choose the 4 pot.

[Ken Figenus]

bearman68 said:

The N47 is a tremendous engine for what it is though. For a 4 cylinder diesel, it's fast and smooth, and revs well.
Downsides are timing chain, and the swirl flaps. (Done both)

Swirls on an 'N' - what year? Just though issue would have gone by an 'N' (having blanked off an E39 and an E61 LCI).

[Fox-]

bearman68 said:

The N47 is a tremendous engine for what it is though. For a 4 cylinder diesel, it's fast and smooth, and revs well.
Downsides are timing chain, and the swirl flaps. (Done both)

It's not particularly fast in a 5 Series.

[Andehh]

Always heard 6 good 4 bad when it comes to BMW engine's (when comparing the two). Admittedly this is the internet where only bad news spreads, so ''4 = bad'' is hardly fair seeing as it is BMW most popular engine size across the entire range by a big margin.

I have the F10 530D and the 6 cylinder + Auto makes for a brilliant combination.

[nw942]

One thing you could do to get a feel for possible issues (not just engine) is to visit the BMW Warranty site. Have at hand some registration numbers for cars with different engines, and simply get a quote for a one-year warranty.

A friend has recently been quoted ~ £700pa for his 2013 335d. The EGR valve has been replaced on that amongst other things.

My car has a N54 petrol engine, not exactly immune to issues itself, and it is ~ £400.

Although clearly an averaged risk, it gives you BMW/Mondial's view of possible issues.

[bearman68]

Ken Figenus said:

Swirls on an 'N' - what year? Just though issue would have gone by an 'N' (having blanked off an E39 and an E61 LCI).

The one that came to grief with me was a 57 plate.

And no the engine is not fast in a 5 series - but that doesn't stop it being a 'fast' rev happy engine - (for a diesel). I reckon it's a lovely motor for what it is, and understanding there are significant design weaknesses with it.

[Ken Figenus]

bearman68 said:

Ken Figenus said:

Swirls on an 'N' - what year? Just though issue would have gone by an 'N' (having blanked off an E39 and an E61 LCI).

The one that came to grief with me was a 57 plate.

My E61 535d LCI on a 57 plate was an M (less alloy) engine I believe - these are likely have the crumbly swirl flap issue. First N series engine 245bhp introduced in 2008.

[kurt535]

Ken Figenus said:

M series 6 cyl engines - dodgy engine killing swirlflaps.

N Series (as in my new F11 535d Friday) should have no such issues I hope! Its a more alloy evo of the M series - this engine has been around a long time and vac pipes go - other than that 200k+ in an E39 530d and 120k+ in an E61 535d another has been a good experience.

Spool down the turbos nicely, be v gentle when cold and change the oil at 14k or earlier - worked for me...

swirl flaps issue went out post lci 2007 model update?

[Ken Figenus]

kurt535 said:

swirl flaps issue went out post lci 2007 model update?

Allegedly... Much confusing internet 'information' at a the time... I was hoping to get 400,000 miles out of this one so applied belt and braces

[Fox-]

nw942 said:

One thing you could do to get a feel for possible issues (not just engine) is to visit the BMW Warranty site. Have at hand some registration numbers for cars with different engines, and simply get a quote for a one-year warranty.

This won't work as the price is the same across a series - be it a 520d or a 550i. It's a bit weird really as if you've got a 335d M Sport Auto with Adaptive Suspension and every option ever, your warranty will be cheaper than a base 520d with a manual gearbox despite the obvious additional risk. Presumably this is because part of the pricing is based on what the market will bear rather than the actual risk and it's determined the average 5 Series buyer will bear a higher warranty cost than the average 3 Series buyer, so they pay more simply because its a 5 Series even though almost all of the major mechanical components are shared across the 3 and 5 Series range.

[Broaders]

Swirl flaps were not fixed on the 6 cylinder Diesel engines till the F series. They were modified for the 07 lci but still an issue, albeit less so. Had mine removed just to be sure.