mayday

MBTech208,
Can you describe for us how the Flexible Service System (FSS) determines when an oil change is due. Do the systems operate the same on all 2001 and 2002 MB engines? Specifically, does the 2.3L four cylinder C230 engine use the same measurement parameters as the other MB engines for their FSS system? If not, what is the difference?

awiner

The FSS system uses a number of factors in order to calculate it's decision. Air Temp, Oil Temp, Driving Style, How long the engine has been on, Electrical conductivity of the oil, etc....

mbtech208

*cracks knuckles*

Okay, first things first. There are two different types of FSS. Stage 2 and Stage 3. Stage 2 came with the 104, 119, 120, 606 diesel, and all 111 engines after 6/1/97. Stage 3 comes with the 112, 113, and 137 engines. I'm going to copy this from the FSS manual.

"The FSS is an engine oil maintenance system based on actual vehicle requirements. This means that in addition to the pure time and mileage criteria, various other factors are taken into consideration in determining the actual inspection intervals required. These include quality factors coded with the HHT as well as other evaluation factors which take the type of operation and therefore actual wear and deterioration into consideration. After dropping below a warning limit the remaining mileage or remaining time appears in the instrument cluster and the tool symbol is shown in the display.
The Stage 3 FSS also has a filling level indicator for the engine oil. If the oil level is too low or too high, it is indicated in the text field and the oil can symbol appears in the display.
The complexity of the FSS makes it necessary for it to be equipped with its own processor in the instrument cluster.
FSS obtains the time information from the electronic clock integrated into the instrument cluster. The other data required is received via the CAN data bus from the traction system control module and engine control module:

-4 wheel speed signals for calculation of speed and mileage
-Coolant temperature (a cold climate will make the FSS come up sooner)
-Engine oil temperature(Cold oil will make the FSS come up sooner)
-Oil level(Running the engine with low oil makes the FSS come up sooner)
-RPM(High RPMs will make the FSS come up sooner)
-Load torque(Heavy throttle foot will make the FSS come up sooner)
-Oil correction factor (Stage 3 only)


EVALUATION FACTORS(dependent on actual operating conditions)

-Load torque
-RPM
-Coolant temperature used only as substitute value for engine oil temperature in Stage 3 systems.
-Oil level only (Stage 2)
-The oil level, engine oil temperature, and oil correction factor are provided by the engine control module via the oil sensor (oil level/temperature/quality) Stage 3 only
-Engine oil temperature, Stage 3"

What the "correction factor" is is this: Let's say your FSS says you're due for an A-service in 5,000 more miles. But you don't want to wait, so you take your car in for an oil change sooner. The FSS oil sensor will recognize this new oil, and extend the A-service until a later mileage. It's like a "bonus". But the absolute maximum mileage between services is 20,000 miles. So if you change your oil every 3,000 miles, the FSS will keep extending your next service until 20,000 miles have gone by. That's the point you will have to take it in for an A or B service. This also works for topping up the oil. If you're a quart low, the car will tell you it's a quart low. Once you add that quart, the sensor will recognize a quart of clean, fresh oil and extend the FSS due date accordingly.

Also, if you don't drive your car much, it will call for a B-service if the maximum amount of time goes by. I recently did a B-service on a 2000 S500 with just over 8,000 miles on it. The car hadn't had a service since it was new in January of 2000. The FSS timer recognized this and called for a B-service.

awiner

Interesting point is that many people that have changed their oil inbetween the A/B services have NOT noticed an extension of the FSS mileage. I change my oil at 3000 miles and so far have not seen any lengthening of the mileage for my A-service. I will change the oil again at 7000 miles. We will see what happens then. My goal is to get the A-Service around 11,000 (and that's pretty close to what the FSS is calling for now....)

Jerry Schwartz

Is the synthetic oil included ( no extra charge ) when a 2002 is taken in per the FSS ? What brand oil is used ?

awiner

Yes, synthetic oil is used on all 2000+ FSS vehicles now. Most dealers use Mobil 1, however it has been reported that some dealers are using Castrol or other approved synthetics.

awiner

As a side note here, I finally got my first FSS service today. FSS called for service at 13,300 miles with approx 500 miles left on the FSS clock.

So, yes, frequent oil changes DO extend the FSS mileage above the 10,000 mile mark.

Another intersting note is that my FSS service indicator changed from a A-Service to a B-Service once the clock hit 14 months 0 days. FSS forces a B-Service if you got over the 13 month mark between service intervals.

patrick

How old is your car? 40 years?

patrick

For the new MB-engines that are coming a new type of oil will be required. Some oil manufacturers already have made this new type especially for MB. I think mobil calls it Formula MB SHC.
For this moment only 5 oil manufacturers in the whole world already have oil that meets these new standards.