I understand that Amsoil as well as a few others are recommending 0W-30 oil as a "pure" synthetic solution as an alternative to the 5W-20 that our cars need, since Amsoil doesn't seem to have 5W-20 in the Series 2000 line. Will using that affect the gas mileage in any way?

I'm concerned that non-spec oil will result in poorer mileage...

On a related topic, I just had my first A1 service last week and I went to the dealer. Ever since then, my gas mileage has gone down appreciably. My highway to city driving ratio is about 3:1, and according to my trip computer, I'm only getting 25mpg. Couple this with a relatively small fuel tank (my Altima's fuel tank was 20 gallons, giving me an effective range of about 500 miles prior to me adding headers). My admittedly uneducated suspicion is that the dealer did what many here suspect dealers do, and they just grabbed the single oil dispenser that they use for all oil changes for all other Acura models, and it might not be the right weight.

So back to the question. Does that "30" in the 0W/30 mean that the oil will fundamentally be thicker at higher temperatures? And if so, will that equate to lower mileage?

 

30 weight oils are historically more durable than 20 weight.

& no, you will see no efficiency drop in moving to 30 weight oil.

based on numerous rwal world used oil analysis test, m-1 5w-30 is the best oil for our car.

If your going to change your oil every 3000 miles, it really doesn't matter what you get. Most every oil will stay in grade for that length.

rb

 

The UOA's I have seen for Motorcraft synblend 5w20 are outstanding. A 5w30 may be OK, but it will likely contain more VI improver. Plus, the viscosity recommended by the mfr factors into oil flow rates and other variables idiosyyncratic to the engine design. After break-in, I will be going with the Motorcraft product, with a 5k OCI, watching for lead, iron, and other wear metals. Unless I see something way off the mark, I will stick with Acura's recommendation.