X35d CBS-Indicated Oil Change at 9000 Miles

[scchang]

I was planning to do a change every 7500, but this may make it unnecessary (changed at 1200 and am overdue for the 8750 change):

Brought our 2010 X35d to dealer for a couple warranty items. Vehicle info indicated oil change due soon (have 9000 miles). SA said that diesels seem to require oil changes every 8-10K miles. Has anyone heard this?

[Penguin]

Yup, mine asked for an oil change at 9300 miles, and now at 14,000 it is showing 4,000 miles to the next oil change.

[scchang]

Originally Posted by Penguin

Yup, mine asked for an oil change at 9300 miles, and now at 14,000 it is showing 4,000 miles to the next oil change.

I assume you're not doing an interim change every 4500!

[ard]

My CBS hit at 11k ish. I'd done it myself at 7k.

[Penguin]

Originally Posted by scchang

I assume you're not doing an interim change every 4500!

You have identified my quandary.

I did a first oil change somewhere below 2K, and planned on intermediate changes. But 4,000 seems a bit low, even though diesels typically need more frequent oil changes due to soot and more blowby.

So here I am with 4K to go with eight quarts of oil and a filter in the garage, and wondering if I should change it. If it wasn't for the indicator, I'd probably be changing it every 6K or so.

[FunfDreisig]

There seems to be a wide range of mileage reported for the initial (and subsequent) 35d CBS Oil Service: 9k-13k. I wonder what exactly is being measured to cause this large a variation?

It seems unlikely that the CBS is based on the actual properties of the oil in the crankcase, since several of us have done intermediate oil/filter changes. And we seem to be experiencing the same wide range as folks who are doing it "by BMW's book". So it must be based on stuff like: number/length of 'trips', avg mph, temps, etc.

Funf Dreisig

[Penguin]

Originally Posted by FunfDreisig

There seems to be a wide range of mileage reported for the initial (and subsequent) 35d CBS Oil Service: 9k-13k. I wonder what exactly is being measured to cause this large a variation?

It seems unlikely that the CBS is based on the actual properties of the oil in the crankcase, since several of us have done intermediate oil/filter changes. And we seem to be experiencing the same wide range as folks who are doing it "by BMW's book". So it must be based on stuff like: number/length of 'trips', avg mph, temps, etc.

Funf Dreisig

FWIW, the vast majority of my miles have been highway, rather than city. Normally, I would expect that city driving would be harder on the oil than highway, so I found the rather quick change to be a surprise.

[scchang]

Originally Posted by Penguin

FWIW, the vast majority of my miles have been highway, rather than city. Normally, I would expect that city driving would be harder on the oil than highway, so I found the rather quick change to be a surprise.

Same here: highway >> city miles.

[FunfDreisig]

Originally Posted by Penguin

FWIW, the vast majority of my miles have been highway, rather than city. Normally, I would expect that city driving would be harder on the oil than highway, so I found the rather quick change to be a surprise.

Exactly!

Most of our miles up until the first CSB were 40mi (one way) trips on back country roads with a lot of hills and included a fair amount of towing of heavy loads (e.g. 2 tons + trailer). Yet our 1st CBS was not till nearly 11k.

I would have thought that towing in hilly terrain would have reduced the miles to the 1st CBS Oil Service. But obviously BMW knows better*

Funf Dreisig

* Thank goodness I did an intermediate oil/filter change at 4K

[AzNMpower32]

BMW used to use the amount of fuel consumed as the maintenance interval between oil changes. Driving that elicits more wear on the engine (short drives, many cold starts, aggressive driving) also consumes more fuel. Don't know if that remains true today.