My switch to synthetic oil, first 1000 miles

[circuitsmith]

For this winter I put Mobil 1 0W-30 + OEM filter.
Hoping for easier starts and better mileage on short trips where the engine barely gets fully warmed up.
Normally I put in whatever major brand (Castrol, Penzoil, Havoline) 5W-30 is on sale.
Car is a 2006 Matrix 5-speed with 29,000 miles.
Driven mostly short trips 2-3 times a week, plus road trips.
Sometimes I skip filter changes when the miles are really low, never more than 6000 miles on a filter.

M1 oil has now been in 1000 miles over 13 weeks.
Over 5 fillups MPG has improved maybe 0.5MPG; ranged 26-28.5.
Engine previously consumed no measurable amount of oil over 6 months and 1500-4000 miles.
I check the dipstick every 1000 miles.
In this 1st 1000 miles it has used 1 cup, topped off.
Oil looks a little darker than previous. Some dino residue getting cleaned off?

[fishexpo101]

Oil consumption is a little weird, but oil looking darker can be attributed to a number of conditions - could be from better cleaning, could be from additive package reacting to something.

Synthetic will have better solvency, so it will clean up the engine a little better than conventional oil. Mobil 1 is also known to run a little on the thinner side, compared to its competitors - many, like you, see an immediate increase in MPG. That "thinness" coupled with short trips, also tends to dilute the oil with fuel, which makes it more likely to be consumed - even if it is a synthetic motor oil.

Best to run another crankcase of this oil through to see exactly what it is doing. Some engines like M1, some don't - a little trial and error is needed to figure out what your engine likes the best.

[circuitsmith]

I did this change mainly out of curiosity about MPG change going from 5w to 0w.
I'm switching back to dino in the spring.
I have a stash of Penzoil 5w-30 I got a couple years ago for $1.90/qt.