You are correct... Not sure what I was thinking on the 50/50 blend thing. [:@]

 

The reason Synthetic last longer than regular Crude oil.

I drew A description on paint and didn't use Sp Check sorry.
each one of the lines representsone oil molecule

Synthetic oiltakes longer to break down because there are many more of molecules. The same properties in a crude oil5W20 oil are in a Synthetic 5W20 oil , just lots more of them.
Synthetic oil and Crude oil has the same molecular stricture as far as atoms per molecule go, but, the crude oil is random in design, (nature) and synthetic is man made so it can be manipulated to hold more molecules in the same amount of space, And therefore oil with longer life.

[IMG]local://upfiles/58274/3A6C9035B7D644279E695559AC0C9CFB.jpg[/IMG]

 

Frequent oil changes are more important during the 1st 12,000 miles. I switched to synthetic and went 3,000 for the first few, now I shoot for 3,000, but I don't get around to it until 5,000, which is still probably overkill. As has been mentioned, it's the dirt, not the degradation, that will do you in. If a synthetic could be kept perfectly clean, it would probably be good for more than 15,000.

 

Actually some of the GIII based synthetics are very good. I dont see Ferrari having to much problem with the F1 cars. (Shell Helix Ultra is GIII based).

Right off the top of my head I cant think of any 5W-20 that meets SM GF-4 and doesnt contain some GIII. XL-7500 is the only Amsoil that meets this (A Ford requirement if you like your warranty). Mobil 1 was the last hold out of the mainstream synthetics. Alas this no longer seems to be the case. Pennzoil Platinum is no longer GV either. Now GIII. Although it appears to be Shell XHVI (Same basestock as Shell Helix Ultra).

 

Oil and filter is changed every 3000 miles.

 

I just changed mine after at least 7000 miles on it. The Mobil 1 was not as pretty as new, but still working hard. Now, I'm not working in Dallas anymore, so I will not be putting as many miles on the car. Thanks goodness!