Nicholi2007

Here's the overview. I have 122,000 miles on the car. No CELs.

EPA Says 17 City. Highway 25

The manifold was repaired at 81,000.

Tire pressure is not an issue.

I did replace the plugs some 20,000 miles past service. I know.... Everything else has been done on time.

MPG has taken a dive to 13.7 (from start). I would think at a min that 15 to 16 should be the average.

Recently replaced the fuel injection hose as it was seeping.

I am doing a lot of city driving but that's been the case for some time.

Current Symptoms

• Odd noise when doing turn around in driveway
• Consuming 1 quart or more between oil changes

Q. Manual states Fuel filter at 150,000 miles. That seems high. I would have thought sooner....

If anyone has some thoughts or actual experience at this mileage point, please comment below. Thanks!

Moto_Guzzi

They told me the feulpump & filter is one unit to be replaced.

When you touch up oil, is it same oil as spec, or how do you know if correct oil spec was used-?

What do you mean by turn around, going forward left or right, or reverse involved-?

Nicholi2007

1. I only use Mercedes Branded Oil 5W40. It's possible that the dealer added the lighter blend. That only relates to cold temperatures. I don't see how that would have affect it much
2. Turnaround on side street into some one's driveways and turning around.

Q. At what mileage did you change the fuel filter and fuel pump?

I have Your Mechanic (mobile mechanic) coming to do an inspection on wed.

Alfadude

That 13.7mpg, what was it before? And over what kind of distance was that? If it was like 10 miles as opposed to 200 miles that would make a big difference. If you do a lot of short trips and do a lot of stop and go driving, that mileage might not be unusual. Has anything changed recently with your driving habits?

Nicholi2007

Nothing has changed witth driving habits. There is clearly issues somewhere. I'm sure the throttle body probably needs to be cleaned. Maybe even MAF.

I'm specifically looking to hear from others who had a loss in fuel economy with this model car, what was identified, and done.

Obviously this will vary.

I'll see what the 75-point inspection reveals.

Moto_Guzzi

Hi, They told me it lasts very long, I don't have to worry about it, so I did not change the pump/filter combo.
Car at 143 000Km no problems in that regard.

My car developed noise in front shortly after new, they replaced bushes, it also chewed up one tyre on the inside wall, I was lucky to spot it looking underneath from the front, if you walk around the tyres looked ok.

ChazThePhoenix

try running so me seafoam through it. Its help don every car I used it on.

Seafoam

Nicholi2007

I threw in some Lucas and took it for a highway run, Since Start said at 22 MPG.

The inspection found warped rear rotors and my front shocks are almost gone.

I'm thinking of replacing with a Bilstein with a slightly firmer ones. Just not sure....

Probably time to clean the MAF and throttle body....

Nicholi2007

UPDATE:

I've had the front struts and the rear shocks replaced this past week. I will be going in for alignment.

Fuel smell outside of car is still there. I can only smell it above a half tank of gas. Below a half tank, no smell. It seems strongest when tank is full.

Any ideas?

gamma300C

Fuel sender gas tank cover gasket or actual plastic portion of cover leaking/cracked would be my guess on fuel smell. Can access removing rear seat lower cushion.

BTFanC300

Can't say for sure if that's what it is in your case, but my noise/vibration when turning the steering wheel all the way was caused by a faulty planetary gear in the transfer case. Had it fixed by the MB dealer along with a blower motor replacement for 1100$ CAD total and haven't had the issue since.

Nicholi2007

I'm due for a wheel alignment so perhaps that's what it is. thx

Nicholi2007

This would be the fuel pump, correct? There is also a fuel filter.

gamma300C

Yes...I believe a Search will give other posts related to this problem

Nicholi2007

Thanks for the input, I did a search but this issue must be classified from what I could find.

JettaRed

iTrader: (1)

What caused the warped rear rotors? Did they overheat? Could you have stuck calipers, causing additional drag?

Nicholi2007

Just wear. I pushed them beyond the replacement mileage. Once the car hit 100,000 miles, I had bunch of maintenance that just came all at once.

I think I'll start stuff a little earlier to lessen the blow.

JettaRed

iTrader: (1)

That's the thing about maintenance...do it before it becomes repairs.

It is very possible that you have stuck calipers now that are causing the additional drag. Or even a stuck parking brake. The warping is due to excessive heat; something had to cause it. You can always drive the car a little while and then feel if there is a lot of heat coming off the rear wheels. I once had a stuck caliper on my truck that got the entire wheel so hot that it melted the valve stem cap.

Nicholi2007

So evidently the rear differential needs to be done every 4 years or 40,000 miles. Mine was done at 56,00 and I have 129,000.

No one ever suggested I do it so I did not know.

Car feels more responsive. MPG numbers appear to be climbing.

Hopefully that was the fuel economy issue.

xsever

The W204 maintenance booklet says that the rear differential fluids needs to be changed every 4 years or 40k miles ONLY for the C63. As for 4MATIC models and based on all the reading and research I've done, it's only a mileage interval and it's 100k miles. Obviously I am not going to wait that long, but definitely not changing it at 40k miles or 4 years. Maybe 60k miles.

Nicholi2007

You are correct.

I could not find it in the maintenance booklet. Pelican Parts says 80,000 which is the transmission change interval.

xsever

Not a bad idea at all to change it along with the transmission fluid and filter but for the 7G+, it's 70k miles as per MB not 80k miles.

Nicholi2007

Is this a fuel additive? The link does not work. Mercedes does not recommend anything except Techron.

Nicholi2007

I had a guy come out. Took it off

The seal seemed ok. No cracks. The cover was actually black not white.

I could not see any cracks. I wonder if they are hairline and tough to spot?