I gave them all genuine MB fluids straight from the dealer so it's the not question of using the right kind of fluid...

Requested them do three things.

1. Engine oil + engine filter (mobil 1 0-40w + genuine MB filter)
2. Power steering fluid flush (CHF 11s)
3. Rear differential flush (genuine MB rear axle fluid)

While they were flushing PS fluid, they put in too much fluid and oil overflew...

They cleaned the spilled oil with water and pressurized air stream. (This can't be good for components inside the car right?...)

Anyways I thought it was all good until I noticed about 4~5mpg DROP than usual (mpg calculated as per onboard computer)...
I usually get about 32mpg on highway and now I get around 27mpg...
I usually get 20~21mpg in the city and now I get around 16mpg...

Did they mess up something? Maybe they touched the mass air flow sensor when they were cleaning spilled oil?
The car was actually driving at around 32mpg for couple days AFTER it was serviced by the indy shop..so it was fine for a while..
It's been about a week since it got serviced and I just noticed the drop in MPG 2 days ago..
I plan to go back and complain but it'd be great if you guys can give me some pointers on what might've gone wrong..

This is for 2002 C230 Kompressor with 120k mileage.

Service history:
2012/July: ATF, ATF filter, brake fluid, engine oil, engine filter, cabin filter, engine air filter, spark plug, coolant flush, fuel filter, serpentine belts

2013/December: engine oil, engine filter, ps fluid, rear differential


PS: And no I drive like a baby and my driving habits did not change to explain this drop...

 

netddos,

Sorry to hear of the problem. You obviously care for your car well.

I am puzzled why anyone would clean up oil with water as they do not mix & a worse mess would result.

Have you had any codes come up ?

You do not say where you live. Has the snow & cold weather arrived. Has the fuel changed to winter fuel ?

JC

 

I plan to keep this car until it's wheels come off so I do what I can to minimize the wear on the car.

I have no diagnostic module to connect to so don't know if there are any codes right now... No check engine light or any of that kind however...

I live in CA so despite being winter it isn't THAT cold..around 60-70 sometimes 80s...I'm really hoping it's some shady gas station mixing ethanol in their supposedly 91octane gas..tho I tried to fill gas from different station to dilute the previous gas and it had no effect.. I did use chevron fuel system cleaner about a month ago too...

Winter fuel? How do I know whether it's winter gas or not? Never knew there were winter gas and summer gas separately..

 

It's certainly not caused by the oil unless it has been hopelessly overfilled.

It could be winter gas or gas with a very heavy alcohol dose by mistake being CA.

 

A can of PS fluid was around 1 qt so I can't imagine being overfilled too much.
I did, however, had to suck out some PS fluid because it was still leaking out little bit from the reservoir. (So much for professionalism..)

That being said, even if oil spill wasn't that bad, the water they used to clean might have done something? maybe? I thought MAF sensors are supposed to be sensitive to water?

I always pay close attention to MPG and I've never seen a drop like this during Winter...California doesn't even get that cold to begin with..
I've been driving this vehicle for over 7 years in California so I should know..

I'm really hoping it's just the fake gas from a shady gas station...for that we will have to wait until I waste all the gas..

 

If there is something wrong with the MAF, I'd say with 99% certainty you'd then also have your CEL on and you'd have drivability issues. If you don't have either one, the reason is somewhere else than at what the shop did.

 

Sorry ~ I was talking about the engine oil being drastically overfilled.

 

Just a thought. I wonder whether the PS oil over spray/cleaning water entered the air cleaner therefore blocking it partially & now giving the engine a richer mixture . Worth a look. JC

 

Yes. A wet swolen air filter element would enrich mixture.

 

Thanks
I will check

 

What about O2 sensor going south?

 

Okay the shop says maf and o2 sensors can't be affected just because of little oil spill and water clean up. They are probably right.

While on fwy for 90% of the time today my mpg came out to be around 33. Which is pretty damn good! I put in a bottle of techron complete fuel cleaner the night before and maybe it is helping.

Despite all that I feel as though my mpg in the city is still abnormally low, around 12~17mpg.
It seems like mpg drops really fast while I'm stopped at the light. Of course some drop is expected but feels like it's dropping faster the before.

What could affect my idle mpg? Would cleaning the throttle body help I this case? MAF clean up? I see so many maf horror stories that I'm afraid I should stick with the adage " if it ain't broke don't fix it"

What do you think?

 

Is your idle speed higher than normal? I am not sure what model engine you have, but have you checked the drive belt to make sure it's not slipping due to PS fluid contamination?

 

I don't think so? Not by a noticeable amount..?
I never kept track of idle rpm so nothing empirical no...but not enough for me to notice the difference.

But nice suggestion. Will check.