The main reason North American vehicles are being spec'd with 5w20 oil has little to do with the engine or vehicle use. It has mainly to do with EPA fuel economy ratings. The thinner oil shows better results during fuel consumption testing and is therefore used by most manufacturers in an effort to get the best results possible. Remember, the testing is done by an independant agency, but manufacturers must post the results on window stickers, etc.

It is one of the factors that a manufacturer can't change or they have to have the vehicle retested. Same thing with the transmission delay reflash of the Transmission control module. Because it can change emissions/economy, Mitsubishi, by law, must place a sticker under the hood showing the updated code levels and their effect on the emissions, etc.

I actually changed the oil from 5w20 synthetic I put in at the begining of the winter to a higher quality 5w40 synthetic and the engine starts much quieter and runs smoother all around. Just anecdotal.

 

use napa gold or wix. i use that.

 

also,
What I notice in MPG is what weight oil your using thats all. Currently have 5w30 and MPG is at its worst. I think im going back to 5w20 syn.

 

so I went to my local walmart and see mobil 1 0w-20 Advance fuel economy.

Here is more info:

http://www.mobiloil.com/USA-English/...l_1_0W-20.aspx

It says it can be used in 5w-20 engines and protect the same. I was about to get this but need more info.

Has anyone put that in? or recommend it?

 

I don't have any experience with synthetic or "0w" rated oils, but i'd love to see some real world results on the mileage figures for them.

I had my oil changed at the dealer and they used Mobil 5000 5w-30. I didn't think it was doing so well until i recently tooka 400 mile round trip and going there got22.3 MPG @ 70-mph avg and returning got 24.6 MPG @ 74-mph avg. Both legs were on full tanks with loaded vehicle (wife, 2 kids in car seats, luggage, a small dog and newly added hitch = 300+ lbs). Funny thing too, the first leg there was in 2wd and the return trip was in 4wd Auto mode.

If 5w20 synthetic adds miles to those numbersi'd switch in a second. Eager to hear the results.

 

I think the difference between 5w20 and 5w30 MPG wise is 1 or 2%..which is unnoticeable outside a lab. I doubt the 0w20 will be much difference.I think it's more a product of Mobil's marketing department than the engineering dept.

 

I go to walmarts oil center, I only go to a chosen few though. I use Castrol, because of some crap the Mobil has done with their synthetics that is related to using them in motorcycles I wont use Mobil. I actually use diesel oil in both of my sport bikes.

I also wont use synthetic before 10k miles.

Anyways, the walmart brand filters are made by champion labs, the same makers of the mobil filters. They also test the same. They are highly regarded on many vehicle forums.

 

well I'll guess I'll go ahead and buy the new mobil 1 0w-20 and test it out.

I had m1 5w-20 full syn before and the mpg was really great @ around 24-27.6 normal drive conditions.

So far on my observations on using mobil 1 5w-30 full synright now @ 11,500 miles, I get about 22-23 mpg on highways and sometimes i get 23.2-24.3 on long trips (40 mins) andget about290 miles out of a full tank. Based on differental temps/pressure here in seattle. MPG got bad/ok

So my next oil change is comingup and I am going to change to the 0w-20 adv. fuel econ. and see how it makes a difference.

Then using the same adv. fuelecon. oil next oil change after 0w-20, I will then use 0w-30.

Basically I am testing which oil from 5w-20(past), 5w-30(past), 0w-20(current), 0w-30(next), 10w-30(summer/future).

So far 5w-20 is the current winner in fuel economy.

 

Holy cow! 24-27 mpg! That's crazy good. What drive mode are you usuallyin (2wd/4-Auto/4-Lock)? I may have to try the 5w20 synthetic stuff it that kinda mileage isthe norm.

 

I only got 2wd on this! no awd...sadly[&:]

oh yeah the 24-27 mpg is on the freeway only. I havn't recorded city which i don't really care since I do alot of 40 min drive.