Oil Change by Time vs Miles

[rc'Z]

For those of you that have owned your Z's for a few years, does the computer figure you've had the car for a year and should have an oil change, or is it strictly by miles?

[nmulax]

I believe the computer strictly goes by mileage.

[caseysc]

Originally Posted by rc'Z

For those of you that have owned your Z's for a few years, does the computer figure you've had the car for a year and should have an oil change, or is it strictly by miles?

It's calculated based on gallons of fuel used. The harder you drive it, the more fuel used, therefore, the sooner mileage wise it must be serviced.

This post ws on Bimmerfest:

#6 08-10-2008, 02:39 AM
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With the introduction of the E90 also came the next generation of Condition Based Service – CBS4.

The primary change from previous CBS strategies is that the oil service forecast distance remaining is calculated and displayed separately from the time-based or absolute service-due date.

The mileage interval forecast calculation by the DME is primarily based upon an actual fuel consumption variable, which reflects the current driving profile.

It is the total fuel consumption, and not the accumulated mileage, which influences when the next oil service will be forecast as due.

The displayed mileage until due is only a forecast, and begins to decrease at a quicker rate once the remaining percentage drops below 50%.

If the actual fuel consumption profile increases or decreases from baseline averages, the mileage interval forecast will effectively increase or decrease as well.

The learned driver profile (average fuel consumption) is also used to calculate the next forecast mileage after a CBS reset. For this reason, a starting point of up to 30,000 km (19,000 miles) may be expected for a vehicle achieving lower than average fuel consumption.

The oil service will also be forecast as due 24 months after the last CBS reset, and will prompt for the service if the forecast based upon fuel consumption has not been reached.

However, it is recommended in the US market to change the engine oil at least once a year.

The CBS intervals for other maintenance parts, such as the microfilter and spark plugs, are now linked directly to a multiple of the oil service. For this reason, it is important that the oil service counter be set to indicate the correct service currently being forecast.




F. Y. I.

SI B 12 06 08

E90, E91, E92 and E93 with the N51, N52K and N54 engines produced up to 3/08

The engine oil service interval is "flexible", depending on a learned driver profile (average fuel consumption).

When the CBS oil service is reset, the mileage forecast until the next oil service is calculated based upon this current average fuel consumption value or driver profile.

The highest oil service mileage forecast which could be displayed (vehicles achieving less than average fuel consumption) is 19,000 miles.

DME software calculation error, the updated DME software is included with integration level E89X-08-03-510 or higher. N54 engines, E89X-08-03-520 or higher.
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[MMMazing07]

Originally Posted by nmulax

I believe the computer strictly goes by mileage.

not true. the computers determine your intervals by the way you drive. if you do mostly highway driving then your oil change interval will take longer.

[dngrCharlie]

FYI, you do get a free oil change after a year even if your indicator doesn't say you are due. They call it a low-mileage oil change and they don't re-set your counter.

[RichardTS]

If it was truly condition based the car would have a way to measure the oil condition similar to oil analysis. Basing it on fuel consumption alone and calling it condition based is a stretch. That being said true condition based maintenance is the best.

[rc'Z]

Thanks for the replies. I'll call and see if one of the dealers in my area do the 1 year low use free. Only have 4k on the car and it's birthday is in two weeks. At this rate the warrenty will be over before the milage ever calls for an oil change.

[ZEEFOUR]

Originally Posted by caseysc

It's calculated based on gallons of fuel used. The harder you drive it, the more fuel used, therefore, the sooner mileage wise it must be serviced.
.

interesting, but there has to be more variables. Example: 3 days of track driving could possible equal the same fuel consumption of a 900 mile highway trip at 65mph, but the track days is probably 20X harder on the oil therefore requiring a oil change sooner

[GP20]

Originally Posted by MMMazing07

not true. the computers determine your intervals by the way you drive. if you do mostly highway driving then your oil change interval will take longer.

Nope. It's 100% calculated by the gas consumption. Of course when people mostly do freeway driving then they get better gas mileage than city driving.

And of course, on top of that, BMWNA gives you a free annual oil change.