Next Service Due (Huge Drop!!)

[W8PMC]

When i set off for the Continent a couple of weeks ago, my F10 M5 was on 5000 miles & when i started the car the Display would indicate 12000 miles until next service. This seems about right as was expecting my 1st (not including run in service) to be due around 16-18000 miles so all on track.

During my few days of quite intense hoonage, this has dropped to 3700 miles until next service, but i've only covered a further 1000 miles.

Is this measure similar to the fuel gauge where after a blast the range drops significantly on the next fill but then gradually corrects itself over the next couple of hundred miles? What is the next service due measuring, oil quality or is it a measure of driving styles so after 3 days on track the indicator went a long way South but over the next few normal drives it will rise again?

What liquids or components have i sucked the life out of on track (excluding front tyres & a bit of pad wear)?

Thanks in advance

[ChrisMCoupe]

If I was driving as hard as it sounds like you are, I would fully expect (and want to) to be changing the oil every 6000 miles or less. Can't think what other things the computer might think you need, brakes are perhaps taking a beating on track.

[Shaoxter]

My newly fitted front pads went from 30k to 14k miles after 4 laps of the Ring. Now it's back up to 16k.

[RichardM5]

The overall service period is just based on the amount of fuel that's been used. The car projects the expected distance to the target volume of fuel. If you do a prolonged hooning session, then the fuel rate goes up and the corresponding service prediction comes down. A 1000 miles or so of normal driving will see it increase a bit again.

[W8PMC]

ChrisMCoupe said:

If I was driving as hard as it sounds like you are, I would fully expect (and want to) to be changing the oil every 6000 miles or less. Can't think what other things the computer might think you need, brakes are perhaps taking a beating on track.

Brake life (according to the puter) dropped by about 5k miles on track but it was the service interval that took the biggest hammering. Won't be back on track until next Spring so will get an oil change before the Winter though.

[W8PMC]

RichardM5 said:

The overall service period is just based on the amount of fuel that's been used. The car projects the expected distance to the target volume of fuel. If you do a prolonged hooning session, then the fuel rate goes up and the corresponding service prediction comes down. A 1000 miles or so of normal driving will see it increase a bit again.

Thanks. I had thought the puter may have been more intuitive than bust based on fuel used rate (i did get through quite a bit of S/Ul during that 1000 miles.

[Locknut]

In view of the effect of the hoonage as described above, it might be wise to check the engine oil level rather than wait for a warning light.

I believe Mercedes have a system that monitors the quality of the oil as well as the level and temperature. It will respond to refreshing the oil with a top-up by increasing the miles to next service. I don't know if BMW have anything like that.

[W8PMC]

Locknut said:

In view of the effect of the hoonage as described above, it might be wise to check the engine oil level rather than wait for a warning light.

I believe Mercedes have a system that monitors the quality of the oil as well as the level and temperature. It will respond to refreshing the oil with a top-up by increasing the miles to next service. I don't know if BMW have anything like that.

Oil level is spot on as i can get a live measure from the Car's iDrive system. Checked regularly while away & when i got home. Not noticed or read if it checks quality so i may divert that question to a dealer in the vain hope they'd know

[krallicious]

My M3 did this during every trackday. Pads going from new (20k miles) to 5000 miles was my best effort after a very good day at Spa. IME, the service intervals did not rise but I always did mine earlier as the car was driven quite hard.

[W8PMC]

Schoolboy error as i should have checked all the Service items & it would have become obvious as when the Dash says next service due, it doesn't actually mean Service, it means Attention (how was i meant to know that)?

After digging through the iDrive menu & checking each service item, next Oil is still 9000 miles off, next inspection 12000 miles off but rear pads are 3800 miles & front pads 4200 miles so it's the pads that will need attention soon.

One of the Techs at my local dealer said the measure for oil service is based around oil level & (didn't know this) how long it takes to get up to temp as that's the marker for grade degradation.

[RichardM5]

The think with this 'Oil Change is determined by monitoring the oil quality' stuff, is this: Why when I have my oil changed between scheduled oil changes (because I think 18,000 miles is too long for a turbocharged engine, and so do BMW in almost all other markets!) does the oil change schedule remain exactly the same!!

I know for a fact that earlier cars, for example my E46 330i, E46 330d and E39 M5, go simply on the amount of fuel used, you can even display the amount that's been used and the amount left before a change is due.

However, I've recently found that there is also a BMW document regarding the oil sensors in the current crop of dip-stick-less engines. This describes how the sensor measures the effect the dielectric properties of the oil change as it deteriorates which in turn can be measured by the change in characteristics of a capacitance in the oil.

Based on the above, I'd say that current cars use a combination of both fuel used and a sensor. For normal use, say 10,000 miles a year, the fuel used measure is quite adequate. For low mileage users the quality sensor can be used to reduce the interval. I 'think' I've seen this in operation on my dads E60 535d. He only did a couple of thousand miles a year, the service indicator showed the usual amount, about 18K minus the mileage, then one day it suddenly said oil change due. At the time I thought that there must also be a countdown timer, but maybe this was the oil quality sensor kicking in.

[W8PMC]

The Technician said the sensor is near the bottom of the sump & measures oil quality, oil temps, has a timer & measures levels (not sure how it measures level from near the bottom).

As with most Technician info, it sounds very believable but hard to know for sure.

Just glad it's my fault & my misunderstanding & that the car requires attention in 3800 miles & not an actual service as the display would have lead me to believe.

[Locknut]

I mentioned the Mercedes sensor a few posts back and wondered if BMW has something similar. There's something about it here (have a look at the PDFs in the second post):

http://www.benzworld.org/forums/w208-clk-class/171...

This seems to bear out RichardM5's post.

Edited by Locknut on Wednesday 24th September 23:34