I just bought Mobile 1 full synthetic extended Perfomance witht the filter to match.There claiming I only need to change my oil 15,000 miles or one year. Some companies lie about the product and put out bogus numbers.Does anybody know if there is any truth to this?

I run the same and change every 6000 to 7000 miles.

My Dad worked in the petroleum sales market for his entire career. He always told me that every 6,000 to 7,500 miles is just fine in between oil and filter changes. Anything less you are wasting money. I've followed that rule since and have had no oil related problems with any of my vehicles.

I not only use synthetic oil and change it every few thousand miles, but also I run the longer filter. It'* for the 4.3L V6, namely the AC Delco PF 52.

If i was going to pay the big bucks for Mobile1, I sure as **** would be driving it for a good while. I believe it would be good for 15,000 in ideal conditions, with no incomplete warn-up cycles, and with minimal cylinder wear. Even so, I would change the filter and top it off at mid distance, to be on the safe side.

If it were me, I would go 10,000 - 12,000 at the most. And only if it were all during warm weather.
If your engine is at less than 50K miles, and you rack alot of miles up, then I would say run it until 10,000 and see what it looks like.

My 2 cents.

Very little can be told from looking at oil. Dirty? Yes or no. That'* about it. There are companies out there that test your oil and see what'* up. It'* much safer than looking for stuff and changing the oil once you find it. My few cents, but running 10K miles probably won't harm much. Just don't race the car, as stated.

i wouldnt leave my oil in the car for a year . thats way too long.

I run Mobil 1 and use my oil life monitor, it runs about 9000 miles to 0% "Life Remaining". But the N* is an aluminum block with aluminum heads. We had a thread quite away'* back now, I need to find it and make a sticky of it. Several things were found in the researching that went on while the thread was active. An exhaustive independent study of alot of factors showed Amsoil first, Mobile1 second, Royal Purple third. Royal Purple was first new, though it showed a surprising loss of qualities early on in the tests. Strong starter, didn't keep up. Poor results for what they want for it. When oil contaminants were examined along the way, synthetics in general stopped gaining percentages of various metal ions as they went along. The tests tend to show the synthetics protect better as they went along. Some were took to over 15,000 miles and still showed good lubricating qualities. With 9000miles between changes on Mobil1, mine was dark amber but not anything like Dino oil at 3000. You could still detect transparency in it. Car just had it'* 4th change At 36k miles. Not including the first one I did at 1000 miles after new.

Reasoning for this? I only drive less than 6K a year & been splitting this on 3 vehicles, so I can't see the sense of changing after 1-2K. On the other hand when I drove more I changed every 6 months regardless worked out to 6-7K.

Another reason I changed over to full synthetic, too. Mobile 1 used to be $2-$2.50/qt now what does it run? ... Oil has dropped why hasn't the price of motor oil on the shelf?

One other observation, Someone said in another thread to go from a 0w30 or 5w30 weight up to a 10w30 weight (bottom number is cold weight, right?) my understanding in the cold engine, 10 weight wouldn't circulate as fast. If I lived in a warm climate great, but seemingly below freezing here for more than 6 months out of the year & below zero for 3 or 4 months, I would think a 0 weight oil would be more versitle, as when the car runs to temp it would end up * a 30 weight regardless.... right or wrong?

I knew someone who drove a lot & changed oil 1-2 times a year, however changed filters every couple months.

The bottom number is the viscosity rating at 0F and the upper number is the viscosity rating at operating temperature. So a multi-viscosity oil of 5w30 means that the oil will have no lower a viscosity of 5 at 0F and will not thin out more than 30 at operating temperature.