I have 123k miles on my 2005 4.6 Mustang GT. I have used synthetic or syn blend 5-20 its entire life with Motorcraft filters. The engine is as quiet as it was the day I bought it. Key to these 3 valve engines is good quality oil with a nice additive package and 4-5 k oil changes and Motorcraft...
I bought full syn there several years ago and it seemed to be thin and clear compared to Mobil 1. went back to my regular brand after 3000 miles. I just didn't feel comfortable looking at it after that.
cold temperatures effect the mileage I get alot. I watch the tire air pressure closely and still lose 1-2 mpg. Some gas is just junk. I get the best results with shell regular. I get about .75 miles per gallon better year round and up to 1-2 mpg more on the highway. Cant explain it but it is...
I have used it in my Shelby a few times. It seems to be good oil but I heard it can shear down to 40wt. if driven hard. I think a guy with a Porsche posted somewhere on it. I might go get me some before the sale ends.
There are thousands of crown vics still on the road after the police run the stuffing out of them on motorcraft syn. There are pretty good reports back from the labs after 6-7000 miles too. My 4.6 motor loves the stuff. 88k miles and purs like a cat. I have switched to whats on sale too but...
09 Sonata 2.4 OUT Hyundai oil and filter
29000 mi IN Valvoline next gen 5w20 and Pure One
05 Mustang GT OUT Castrol GTX
87000 mi IN Casttrol GTX 5w20 Motorcraft filter
07 Fusion 3.0 OUT Valvoline Durablend
47000 mi IN Motorcraft Blend 5w20 motorcraft filter