the mileage thing is a myth so disregard that. i personally use mobil 1 full synth. new filter and a little over 4 quarts every 3k mi. the only downside is the price.

 

Isn't one benefit of synthetic supposed to be a much longer period in between changes?

 

yes...i asked this same question a few months back. i put in mobil 1 synhetic at 8k miles on my 3 and don't plan on changing it til 14k

 

you can leave it in longer but i dont. and judging visually by the amount of impurities in it after those 3k i personally wouldnt want it in my engine much longer.

jptech, is your filter good for 6k mi?

 

I have a filter that will keep synthetic clean for 12000 miles.

Got stacks and stacks of lab results to back it up too. 4 micron filtration and higher flow than any other filter available. (at least, I havent found any better yet)

Engine support filters rawk.

 

Geez, TX, those filters sound amazing...

I used the factory-recommended Motorcraft Premuim Synthetic Blend (mineral base oil and synthetic base oil in a blend) until 25,000 miles and changed it and the filter every 2500 miles.

I now use one of two oils; BMW 5W-30 High Performance Full Synthetic because I can get it for wholesale and the other oil I like to use is Mobil 1 RACING 0W-30 synthetic, but it's not as convenient to get hold of and is far more expensive. Mobil 1's RACING formulation includes more zinc, which is a great extreme pressure additive for things like the camshaft lobe/lifter or bucket interface. Manufacturers are using less zinc in their oils because of emissions, rumor has it.

In either case, I leave the full syn in for 5000 miles. I also use the Motorcraft oil filter FL-910 for my 2.3 Duratec.

Now there are what's called Extended drain, or extended service synthetics which have a larger concentration of their additive package. Things like anti-wear, anti-friction, corrosion inhibitors, etc.

A synthetic oil will not degrade as quickly when subjected to heat, and more additives mean that they will continue to do their job well past 7.000 miles or whatever.

I choose to continue to be a little extravagant and change my oil more frequently because engine oil accumilates dirt and other corrosives from water (condenstaion), fuel and acids from the combustion process.

No matter how much of a quantity of additives a manufacturer adds to their oil, I am not comfortable leaving oil in my crankcase that long so I'll prolly never use those extended drain interval oils.

Finally, opinions, especially on oil and oil changes, run deep due to different people's education, upbringing, family habits, brand loyalty, experience, favorite racing cars, race drivers and sponsors, etc. so please, consider my post merely an opinion and leave it at that.

 

TXFO, What filter do you use? I'm going to get one

I think I'm going to switch over to AMSOIL 5W-20 Synthetic with an appropriate filter for their 7,500-mile change plan. I think I'll still change it every 5 or 6k though.

 

I swear by Redline synthetic oil, but it's pricey stuff. 5 quarts plus shipping and sales tax runs just shy of $50.