[Paul J Donnan]

Just taken delivery M40d

Does anyone know if you have to run in new diesels. Ask my dealer on delivery and he said no.
I have read that this is not true and even modern Diesel engines require run in periods.
If this is true does anyone know how long for

[D69GMB]

I would just drive it normally. I think the days of running in cars is long gone. When I get my 40d I will be exercising it to various degrees but will be bedding the brakes in a bit at the beginnng. I would say just drive it normally for the first 1200 miles but give a wee opening up every now and then.

[MechX3M40i]

Maybe the video in this thread can help...

Great video about the break-in period https://x3.xbimmers.com/forums/showthread.php?t=1484459

[teaston]

Just keep it a bit sensible for the first 1200 miles, no WOT for extended periods, especially when not fully warmed up.

Be warned the temp guage is water, not oil like on the F30! When it says it's up to temp the oil is still only about 50-60°C!

[nogren]

I believe your manual says not over 3500 rpms the first 2000km/1300miles.
Usually not that hard with a diesel to stay at low rpms.

[HighlandPete]

Originally Posted by Paul J Donnan

Just taken delivery M40d

Does anyone know if you have to run in new diesels. Ask my dealer on delivery and he said no.
I have read that this is not true and even modern Diesel engines require run in periods.
If this is true does anyone know how long for

Do you trust someone in the dealer for info on break-in period/mileage?

Strange that dealer's don't seem to know that all the published info (by BMW) have specific break-in detail.

BTW, it isn't just the engine that requires a break-in or bedding-in mileage.

Besides the engine and drivetrain, brakes and tyres, also benefit from bedding in.

[Lux700]

Just consider... a new engine is made up from freshly manufactured metal components and many moving mechanical parts interacting with one another, so some mechanical symapathy is required to allow parts to bed in with each other. Warm up by driving off gently and building up to just going with the normal flow of traffic, vary revs and not too much load. For every 100 miles add a few more revs and a tad more load, just a gradual build up... before you know it, there’ll be a few thousands miles on the clock!

Just bear in mind that good quality engines can still be bedding in even after 20k! Also important, don’t mollycoddle it too much either.

[teaston]

Originally Posted by Lux700

Just consider... a new engine is made up from freshly manufactured metal components and many moving mechanical parts interacting with one another, so some mechanical symapathy is required to allow parts to bed in with each other. Warm up by driving off gently and building up to just going with the normal flow of traffic, vary revs and not too much load. For every 100 miles add a few more revs and a tad more load, just a gradual build up... before you know it, there'll be a few thousands miles on the clock!

Just bear in mind that good quality engines can still be bedding in even after 20k! Also important, don't mollycoddle it too much either.

They do actually run in the engines in the factory before they're fitted to the cars, have done for donkeys years now. It's more the gearbox, drivelines and all the connections in between that benefit most from running in.

[Paul J Donnan]

Thanks to all who replied

I will take fellow owners advice, makes sense.

Dealers don't seem to know a lot. More interested in sale than customer service.

[spangle1980]

AS per another thread - I ignored all that stuff above and just owned it from day one - have done on the previous 35d and the 30d before that :->

[Lux700]

IOM race bikes, brand new, 2 laps of the island and job done.. run in!