[Danny.B.]

Hi Folks

Just a quick one, my CBS says i dont need a service for around 7000 miles, now ive had the car jut over a year now so i want to change the oil now.

Would it let me reset the oil service this early?

[makkan00]

Originally Posted by Danny.B.

Hi Folks

Just a quick one, my CBS says i dont need a service for around 7000 miles, now ive had the car jut over a year now so i want to change the oil now.

Would it let me reset the oil service this early?

When the oil is changed, sensor will check its condition and it will automatically show you how much mileages you can do on the new oil.

I am going to do mine as well though I've 9K left.

[Kerr]

Does it actually monitor the condition of the oil or just guess by determining how the car has been driven?

[zltm089]

Originally Posted by makkan00

When the oil is changed, sensor will check its condition and it will automatically show you how much mileages you can do on the new oil.

I am going to do mine as well though I've 9K left.

hmmm are you sure about this?...

I though that the indicator was just like a "timer"...tells you when approx to change the oil....based on time/ mileage...but it doesn't actually "test" if the oil is still fine or not...

[Danny.B.]

Originally Posted by makkan00

When the oil is changed, sensor will check its condition and it will automatically show you how much mileages you can do on the new oil.

I am going to do mine as well though I've 9K left.

So i shouldnt have to "reset" the CBS mileage on this one then?

[Kerr]

Originally Posted by Danny.B.

So i shouldnt have to "reset" the CBS mileage on this one then?

Why are you changing the oil now?

If you want to shorten the oil change services why not just leave it and change it again when the real service is required?

[Danny.B.]

Thats a good call.

I felt like it should be done as its been over a year now since its last been done!

[makkan00]

Originally Posted by Kerr

Does it actually monitor the condition of the oil or just guess by determining how the car has been driven?

I'm sure that I read in TIS description of oil pan sensor that it checks the density of the oil and the amount of thickness to determine how much mileages your car can do.

[makkan00]

Originally Posted by zltm089

hmmm are you sure about this?...

I though that the indicator was just like a "timer"...tells you when approx to change the oil....based on time/ mileage...but it doesn't actually "test" if the oil is still fine or not...

According to BMW CBS bulletin

The type of CBS components supported on a particular model will vary depending on specification and enginetype. Items fall into 2 main groups:

1) Sensor based items
These items are monitored by physical and virtual sensors with some reference being made to variables such as vehicle mileage, driving styles and temperature. Items included in this group are:
-Engine oil – Monitored by the DME/DDE engine control module
-Micro filter/Pollen filter – Monitored by the IHKA climate control module
-Front brake pads – Monitored by the DSC stability control module
-Rear brake pads – Monitored by the DSC stability control module
-Diesel Particulate filter - Monitored by the DME/DDE engine control module

2) Internally calculated items
Certain items monitored by the CBS system do not require physical sensors. These serviceable items still operate under fixed intervals with remaining service life calculated by the instrument cluster based on time and distance. Items included in this group are:
-Brake fluid
-Spark plugs


Now looking at TIS, here is the description how oil sensor works;

How it works
The oil condition sensor consists of two cylinder capacitors arranged one above the other. The engine oil quality is measured by the lower, smaller capacitor. Two metal tubes are arranged one inside the other as capacitor electrodes. The engine oil is located between the electrodes as an electrical non-conductor (insulator). The electrical material property of the engine oil changes with increasing wear and dissipation of the fuel additive. The changed electrical material properties of the engine oil change the capacitance of the capacitor. This capacitance value is processed in the integrated electronic evaluation unit into a digital signal. The digital sensor signal is passed on as an indication of the engine oil quality to the digital engine electronics (DME). This actual value is processed in the DME to calculate the next engine oil service. The oil level is determined in the top of the sensor. This part of the sensor is located at the height of the oil level in the oil pan. As the oil level falls, the capacitance of the capacitor falls accordingly. This capacitance value is processed by the electronic evaluation unit into a digital signal and also sent to the DME. A temperature sensor has been fitted to the electronic evaluation unit to measure the engine oil temperature.
The oil level, engine oil temperature and engine oil quality are measured continuously from ignition ON.

HTH.

[makkan00]

Originally Posted by Danny.B.

Thats a good call.

I felt like it should be done as its been over a year now since its last been done!

Remember that sensor checks the wear and tear, but not the condensation in the oil. Also, if you do a lot of short journeys, your oil filter will be more susceptible to blockages caused by the condensation of water in the oil.
Same applies to Crankcase breather valve (CCV) and with short trips, when you do not drive on optimal temperatures for engines, condensation increases in the oil ----> oil filter / CCV blockage.

I have simple rule of thumb. BMW tend to change CCV on E46 after every 60K. They have modified the design of CCV on E90 and now recommendations are on 100K or as per required.
I still make E46 as a reference. So if your car is sub 60K, follow CBS.
If you car is more than 60K, I'd ideally change the oil when winter is finishing (to take out oil with plenty of condensation due to weather + short trips).

But then I may be overcautious.

[alzieboy]

Some good info there SAM.

[AlwynMike]

Not done this on an E9x, but certainly on the E6x, the oil is monitored as you said above but the CBS still needs to be reset to give the calculations a "starting point".

Mike

[Danny.B.]

Had a look today and although it would be 7000miles "early" i would only be 4 months early so its not too bad, plus it will take me twice that to to 7000 miles!!

Wants brake fluid too, so ideal time to get some SS brake cables!

[zltm089]

Originally Posted by makkan00

According to BMW CBS bulletin

The type of CBS components supported on a particular model will vary depending on specification and enginetype. Items fall into 2 main groups:

1) Sensor based items
These items are monitored by physical and virtual sensors with some reference being made to variables such as vehicle mileage, driving styles and temperature. Items included in this group are:
-Engine oil – Monitored by the DME/DDE engine control module
-Micro filter/Pollen filter – Monitored by the IHKA climate control module
-Front brake pads – Monitored by the DSC stability control module
-Rear brake pads – Monitored by the DSC stability control module
-Diesel Particulate filter - Monitored by the DME/DDE engine control module

2) Internally calculated items
Certain items monitored by the CBS system do not require physical sensors. These serviceable items still operate under fixed intervals with remaining service life calculated by the instrument cluster based on time and distance. Items included in this group are:
-Brake fluid
-Spark plugs


Now looking at TIS, here is the description how oil sensor works;

How it works
The oil condition sensor consists of two cylinder capacitors arranged one above the other. The engine oil quality is measured by the lower, smaller capacitor. Two metal tubes are arranged one inside the other as capacitor electrodes. The engine oil is located between the electrodes as an electrical non-conductor (insulator). The electrical material property of the engine oil changes with increasing wear and dissipation of the fuel additive. The changed electrical material properties of the engine oil change the capacitance of the capacitor. This capacitance value is processed in the integrated electronic evaluation unit into a digital signal. The digital sensor signal is passed on as an indication of the engine oil quality to the digital engine electronics (DME). This actual value is processed in the DME to calculate the next engine oil service. The oil level is determined in the top of the sensor. This part of the sensor is located at the height of the oil level in the oil pan. As the oil level falls, the capacitance of the capacitor falls accordingly. This capacitance value is processed by the electronic evaluation unit into a digital signal and also sent to the DME. A temperature sensor has been fitted to the electronic evaluation unit to measure the engine oil temperature.
The oil level, engine oil temperature and engine oil quality are measured continuously from ignition ON.

HTH.

Good info! Thanks for that.

[makkan00]

Originally Posted by alzieboy

Some good info there SAM.

Alan.

Originally Posted by AlwynMike

Not done this on an E9x, but certainly on the E6x, the oil is monitored as you said above but the CBS still needs to be reset to give the calculations a "starting point".

Mike

Thats what I did on my E90.

Originally Posted by Danny.B.

Had a look today and although it would be 7000miles "early" i would only be 4 months early so its not too bad, plus it will take me twice that to to 7000 miles!!

Wants brake fluid too, so ideal time to get some SS brake cables!

Danny,
give it another month. Probably at the end of the March, when weather starts settling, that would be ideal time to take out condensed oil.

Originally Posted by zltm089

Good info! Thanks for that.

[mob17]

This is exactly what i'd like to do. Due for its 3rd service in 9000 miles but i want to change the oil now. So, i can do this and not bother about the light as it will be done again in 9000 miles?

What i don't want is the service light being reset automatically, then when the dealer plugs in my key fob they see its not due, when it should be at 46k miles. Don't want to lose my service history!

Should be ok though?

[makkan00]

Originally Posted by mob17

This is exactly what i'd like to do. Due for its 3rd service in 9000 miles but i want to change the oil now. So, i can do this and not bother about the light as it will be done again in 9000 miles?

What i don't want is the service light being reset automatically, then when the dealer plugs in my key fob they see its not due, when it should be at 46k miles. Don't want to lose my service history!

Should be ok though?

Not sure about this though.

What I have noticed is that if I top up oil, it automatically extends the remaining miles for the oil service.

I hope somebody else can answer this.



EDIT: I take it that your car is under warranty and it is low mileage car. Leave it on normal oil service schedule.

[mob17]

Originally Posted by makkan00

Not sure about this though.

What I have noticed is that if I top up oil, it automatically extends the remaining miles for the oil service.

I hope somebody else can answer this.



EDIT: I take it that your car is under warranty and it is low mileage car. Leave it on normal oil service schedule.

Yes it's done 36k, under warranty and should be due in 9000 miles. I just wanted to do it for peace of mind really

My tachometer thing doesn't have an oil level meter. Do you know if this makes a difference?

[dxb335d]

You want to keep the BMW service intervals, so no need to reset, your only doing an "interim" oil change.

[Brian mc21]

On this subject had my oil service done today as I was due a brake fluid change. Oil service had 4000 miles left though thought I would get it done with the brakes. £200 all in in my local stealer which I thought was not too bad.

[mob17]

Originally Posted by dxb335d

You want to keep the BMW service intervals, so no need to reset, your only doing an "interim" oil change.

Agree. I just thought from reading this thread, would the schedule stay exactly the same? Basically i don't want BMW saying "an oil service was done and you have no stamp". Which is what i will be doing.

Anyways i bought the oil today and i'm going to do it and worry about it later. It will probably be fine!

[mistryn]

I have done interim oil changes in the past and did not reset the oil countdown and it did not rest it self either

I would not worry about it, I would change the oil and leave service reminder as it is as I am pretty sure on the E90 it just basis it on your driving style and not an actual sensor inside the sump