Lunacy

just wondering what oil do you guys use?
I'm thinking about switching to mobil 1 synthetice
any suggestions?

xviper

This is what I'm currently using but I waited till the car was broken in first (at about the 10,000 mile mark).

airgate

I started using Mobil 1 from around 12k miles and I currently have 34k miles. Every oil change since 12k miles has been with Mobil 1.

boiler

I'll make it a threesome. I also use Mobil 1 10W30 SuperSyn. I changed to synthetic oil at the third oil change (3750 mile intervals).

Barry in Wyoming

Motor

yellow2001

mobil one

Bret

I have not yet decided what to use in my S2000 yet. In my Nissans, I use Castrol, Mobile, Exxon, or Valvoline... whichever is less expensive at the time.

While we're on the subject, I understand that synthetic oil should be better in theory, but is there any quantitative proof that it really makes an engine last longer in the real world? I don't mind spending extra on synthetic oil if it will make my car last longer, but I don't want to throw away my money either.

Barry in Wyoming

Here's what Consumer Reports thinks:

Motor oil does more than lubricate the engine; it helps the engine run cool and keeps it clean. To help oil do its job, refiners add dispersants, which keep contaminants suspended in the oil, plus rust inhibitors, detergents, and antiwear agents.

Advertising touts big differences in performance among motor oils, but when we tested name-brand oils in taxicabs four years ago, driving each cab 60,000 miles, all the brands worked about the same--very well. We've also found no advantage in using oil additives such as STP or Slick 50.

If the brand doesn't matter, what does? Essentially two characteristics: viscosity and service grade. Viscosity is the oil's ability to flow at a given temperature. The two most commonly recommended grades are 10W-30 and 5W-30. Those are "multiviscosity" or "multigrade" oils, effective over a range of temperatures. In 5W-30 oil, "5" refers to how the oil flows at low temperatures (the lower the number, the easier the oil will flow); "W" means it can be used in winter; "30" refers to how it flows at high temperatures. Other things being equal, a 5W-30 oil will flow better than a 10W-30 at very low temperatures but will behave the same at higher temperatures. Use the grade your car's owner's manual suggests for your climate.

The service grade, on the label, is based on an American Petroleum Institute certification program to ensure that an oil protects against deposits, wear, oxidation, and corrosion. The current grade for cars is SJ.

...
Some synthetic oils, including Mobil 1 and Pennzoil Performax, are pricier than most and didn't give a performance edge in our taxi tests. In our lab tests, however, they flowed particularly well at very low temperatures yet maintained their viscosity at very high temperatures. Such oils may be a good choice if you drive hard in very hot or cold weather, or if you often tow heavy loads.