Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Synthetic oil

Can you extend oil change intervals by using synthetic oil?

Can you, yes.
Should you, no.

While synthetic oil is less susceptable to self destruction under some extreme stresses, it too becomes contaminated with the byproducts of combustion (via blowby) and the microscopic particulates of wear.

My recommendation:
if you want to extend the useful life of your oil, extend your intervals.
If you want to extend the useful life of your engine, stay with the intervals recommended in the owner’s manual.

Personally, I’d rather extend the life of my engine.

Not if you’re still under warranty. If the warranty’s no longer in force, it’s up to you, Mobil1 is available in a version with a 15,000 mile guarantee. Note that regular Mobil1 does NOT have an extended change interval guarantee.

I wouldn’t do it, though.

Probably a little. But don’t do it if you’re under warranty. And I won’t go longer then 7k miles no matter what the oil company says.

If you’re still with us, jeveasey,

Yes, and, yes. At least that has been my experience. I have run Mobil 1 (since 1980)in all my vehicles, Supra, Cressida, Chrysler, Aleros, 10,000 miles. And, last year switched to the new l5,000 mile Mobil 1. HOWEVER, I don’t run Mobil 1 for the extended oil change intervals only. The engines get a much greater degree of protection from this synthetic lubricant that doesn’t break down as do natural lubricants. There are other benefits, also. If you go to the Mobil-Exxon site you’ll see scientific research, along with down-to-Earth explanations, which show all the benefits of using Mobil 1 besides the extended change intervals.

One overlooked item in all the discussions is the ALL-IMPORTANT oil filter. Mobil makes a synthetic fibre filter, which is engineered to last the 15,000 or more miles Mobil 1 may be run in an engine. These can be purchased at AutoZone for around $13. Doesn’t make sense to run Mobil 1 for 15,000 miles through an ordinary paper media filter, no matter how advanced some of those guys say their paper filters are.

One more thing. The WALMRT has just reduced the price of Mobil 1 to $22 for the Imperial gallon (5 qt). Used to be just shy of $30.

Advance Auto Parts Runs A Special A Couple Times A Year. 5 Quarts (Including Extended Performance) And A Mobil-1 Filter For $30. Stock Up.

Yes, and, yes. At least that has been my experience.

That may apply to your car with your type of driving, but not the next guy.

There are other benefits, also. If you go to the Mobil-Exxon site you’ll see scientific research

Since they are selling the stuff, I would have to consider the possibility that the information they present may be less than objective.

Most drivers can extend their oil change intervals without noticeable problems, but that does not mean all nor does it mean that there might be problems down the road. Any one remember SLICK-50?

Joseph, I Agree With You On Some Of This. However, Many Manufacturer’s Specify Synthetic. I’ve Never Seen One Specify “Slick - 50”, Though.

Synthetic is the recommended oil in my car at temperatures below 0 degrees Farenheit and we have many weeks of temperatures below that, where I live. Rather than switch, I just run it all year long.


I would like to know why you want to extend your oil change intervals.

I think it is a bad idea to extend your oil change intervals. When you change your oil, the oil change isn’t the only thing that gets done. A lot of things get checked when you change the oil, and if you extend your oil change intervals, you are less likely to find problems before they leave you stranded somewhere. For example, if you extend your oil change interval from 5,000 miles to 10,000 miles, that slow power steering fluid leak that could have been noticed and fixed for a low cost will lead to the need for a new steering rack. Instead if noticing you have a slow coolant, leak, and fixing it before it becomes a problem, you might either overheat your engine or find yourself stranded on the side of the road.

When I recently changed my oil, I discovered a crack in my radiator. If my oil change interval was twice as long, I might not have discovered it as quickly.