steffen

My FSS has been showing 7000 miles to go to Service A.

I bring it into the dealer because it showed 1 qt low.
The dealer explains that to do this right, they ended up sucking all the oil out and refilling it so they would know that they filled the exactly right amount of oil in.

So I got a free unscheduled oil change. Nice.

As I pulled out of the dealer, I made sure they didn't reset the FSS. No - it still said 7000 miles.

Now (50 miles later) the FSS shows 8100 miles to go to Service A.
There must be some type of check in there where it looks at the quality of the oil.

--Steffen

trench

The V6 motors can check oil quality (and maybe the new 1.8L M271 motors), the old M111 in the 2002 Coupe is incapable of determining this. It could be the computer in your car realized that new oil had been added from the increase in quantity and changed the FSS.

I assume that the sensors in the newer motors check oil quality by measuring the electical resistance of the oil or something like that - which should change as oil the oil becomes contaminated.

However, it seems odd that your dealer would do all this for a 1 quart low reading (especially since they can add the correct amount using the dipstick).

Cheers, BT

dswildfire

really? the m111 can't check the quality? why dd the mileage until service A change then for me? i mean it hasnt changed for service B, but for service A it chnaged according to hard i was driving the car. not saying you're wrong or anything, just curious.

trench

I think the computer simply looks at the way you've been driving (RPM, how hard you accelerate, etc.) and makes a guess to what the oil quality should be like under those driving conditions - harder driving, or more stop and go type driving probably causes it to decrease the time to servicing, while gently cruising on the freeway increases the time.

- BT

dswildfire

i guess that makes sense. thanks trench.

steffen

Well, that wouldn't explain my empirical observation, but I guess it could all be coincidence.

And to answer someone else's question the tech explained that it's easier for them to just remove&replace the oil than to go back and forth, add a bit, check the stick, add more, check the stick, oops, take some out, add more, etc etc.

--Steffen

Matt230K

The people at your dealer are morons, but it's great that you got a free oil change.

Even if they do drain it all and fill it back up, they're gonna have to keep checking it to make sure they get it right. And with sucking it out, you never know exactly how much you get out, so they can't just pour in a certain amount of oil and say it's okay. They would have to do the same check and add as they would if they just topped it off.

c230 sport

Does anyone knows if the new 1.8 engine can check oil quality? If it does, that would be great.

trench

According to mbtech208, the 2.3L M111 motors do not have the oil quality sensor.

The way I explain your empirical observation is that since the car keeps track of the amount of oil in it and more oil is added it takes that into account. So if the car determines that it's a quart low (which is about 13-14% of the total oil volume), then when the oil volume is increased, the car assumes that one quart of new oil was placed into it (which means that the overall oil quality should be better by having new oil added into it by about 13-14%). If you multiply 7000 miles by 13.5% you get ~8000 miles to the next oil change.

Cheers, BT

Lynn

I had an early oil change at 2500 miles and subsequently needed to add a quart at about 6500 miles. The FSS never changed from needing Service A at 10,000 miles.

darkfact

the oil check in mom's car says "oil quality 98%". the car is new.

my car... I drove 4000 Km since last oil change, and the oil check says "oil level ok". though the service people said I should change it every 4000.

Matt230K

If you're talking about 4000 km, that's crazy. That's only 2500 miles. They're just trying to get your money. If you have synthetic oil in your car, you can go much longer than that. Probably 12,000-16,000km with synthetic, if not more than that.

DCXdynodog

Not likely. If it can, it doesn't work very well.

Changed my oil around 5k miles and FSS never changed.