i did a oil change and now my mpg is 13

K

kidfx35

Member
Location
Chicago, IL
Car
2004 FX35 AWD
wassup guys thanks in advance for reading. I just did my oil change after 8000 miles over. previously I had mobil 1 synthentic. to my surprise was only 1 quart and half oil after draining. is this normal I have no leaks. So I put in 5 quarts of Mobil 1 Extended Performance 5W-30 the green bottle http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_Extended_Performance_5W-30.aspx and starting ticking at first with start up but went away after couple hours. then I looked at my mpg on my screen because I felt it was running better the next day and my mpg is down to 12.5mpg or when im stopped it goes to 9.5mpg so I kept hitting reset and it says at around 13mpg before oil change it was at 17.8 anyone ever have this issue?
 
Ignore the mileage reading; it only gives average since you reset it. So if you were getting 17.8 before with mixed highway and city, but then you reset it and have only done city driving, it will read low. Calculate based on miles per tank, it's the only accurate way.

FWIW, I have an AWD and get 11.5mpg in city driving during my daily commute. Stop and go traffic kills mpg since the FX is so heavy. Mixed city/hwy, it's more like 16mpg.
 
oh ok just thought something was wrong with it like what the heck that ruined my day whens something wrong with the fx it makes my day horrible. its just weird seeing it always at 17.8 and now its changing from low 9s to 13 like somethings wrong.
 
Notice any blue smoke coming from tail pip in the morning? that could be very bad news
 
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Well it happend to me, didn't know my oil was that low, so I have been driving with low oil , less than 50% low, that was the beginning of piston rings issues that lead to have my engine replace, hope your situation is not as bad, I would use none synthetic oil for now so it's less likely to seep thru piston ring.

Sent from my SGH-T999 2
 
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Yeah so, probably check your oil level more often from now on if you lost that much.

Also, did you change it after 8k miles, or did you change 8k miles past when you were supposed to change it? What oil did you use for that long?
 
sprtfx - I have done 3 oil changes one with synthetic blend, 2 with full synthetic. I thought it was bad for your engine to go back from synthetic to conventional? stulax18- I used mobil 1 synthetic the regular, and when do you guys check your oil at best in the morning before start up? pull stick wipe put back in then check before starting in the morning? that thing is so hard to read.

---------- Post added at 12:09 PM ---------- Previous post was at 12:08 PM ----------

I changed it after 8k but I knew I was already leaking already around 6k because I had to refill but the stick never said that low of only 1.5 quarts I would have to refill about half a court and would read mid line.
 
Yeah, I dunno to be honest how you would accurately check it. Our dipstick is such a PITA anyway. Why such a long interval? I'm guessing you lose X amount of quarts per 1000 miles, so stretching it to 8k miles magnifies the oil loss. If you run a shorter interval then you would have to worry less about having the correct amount. Maybe after a few changes you can see how much you are losing, and then add about a quart every time you hit that mileage?

I have a M1 5w-30 oil analysis that I just sent in yesterday and it was almost 5k miles, so you can see how the wear looks at that level. Only problem is I forgot to take a sample and had to use the oil from the filter so it's only half of the little bottle they give you. Not sure if they will be able to do all the tests.
 
Car should be on level ground for oil check and most accurate after the car been seating a few hours so that the oil get a chance to drain back down into the oil pan.
 
is that better? never liked switching then other whats recommended 5w-30

---------- Post added at 12:22 PM ---------- Previous post was at 12:21 PM ----------

just to clarify you said you took a 5k oil sample and sent it out to a specialist? wow didn't know you can do that? how much they cost and what are some the things they test for?

---------- Post added at 12:23 PM ---------- Previous post was at 12:22 PM ----------

is that better? never liked switching then other whats recommended 5w-30@ dracula


just to clarify you said you took a 5k oil sample and sent it out to a specialist? wow didn't know you can do that? how much they cost and what are some the things they test for?@ STU
 
no colored smoke so were in the clear

---------- Post added at 01:48 PM ---------- Previous post was at 01:29 PM ----------

this mobil 1 synthetic extended says I can go up to 15k miles with no oil change ill check it at about 1000 to see if im burning oil. what oil do yall use and how long do you change?
 
i wouldnt go up to 15k. I would do regular oil changes at 5k with the regular m1, if you buy extended then add 3-5k more miles to the change.
 
What kind of driving have you done? I just changed my oil and then went to get gas right after so I reset the mpg computer. I'm at like 12 mpg now over 13 miles, all city/parking lots. I just finished getting 20-24 on the highway so I don't think anything is wrong, just that certain driving kills your mileage.
 
Dracula said:
i wouldnt go up to 15k. I would do regular oil changes at 5k with the regular m1, if you buy extended then add 3-5k more miles to the change.
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I run Mobil 1 5w/30w and change it every 5000 miles though they say you can run longer because the synthetic oil isn't broke down at 5,00 miles yet there are suspended contaminates that do accumulate so by changing every 5,000 it keeps engine clean.
I also use a magnetic oil drain plug so any signs of metal in oil will be readily seen. Also at every oil change I add a bottle of fuel system cleaner to a full tank of fuel to keep injectors and fuel system clean.
I have 114,000 miles on my FX and only loose about half a quart every 5,000 mile change.
 
@stu - I do the same but my mpg never change it stayed at 17.8 for both when im in the city and on highway never bounced back and forth. yea ill prally do it around 5k as well just went above because I was slacking. hmmm im loosing 3.5 quarts for over a grace period of 8k miles Ill have to check it sooner thanks everyone for their comments and help.
 
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