hell no it aint cheap but in the long run you have better oil in your car and you have to change it less and i added it up and save $40 bucks a year. this is my first time using this oil or anyone that i know so ill be checking regularly to see how its holding up

 

I change my oil at 5000 mi intervals because I drive a lot and the oil gets up to operating temps.every time the car goes out.
The extended change interval would probably be OK unless you start getting the dreaded milkshake gom inside the filler cap that comes with stop and go driving.I looked at Mobile's web page and they didn't mention stop and go driving in the list of driving conditions.This is by far the most severe operating condition an engine will see.The water and acids that are inexcapable byproducts of combustion never get a chance to boil out of the oil and build up over time.This is what causes the milky deposits inside the filler cap.This stuff is the starting point for sludge and reduces the lubricating properties of the oil.
The 15k oil change interval would probably be OK if it weren't for stop and go driving.
Look at the link in my sig ,bobistheoilguy,they go into great detail about lubes of all kinds.

 

Every 3 months, the oil will sit in the shelf for life but once it is heated up the oil does not go bad it's the Additives. Yes the oil keeps lubricating but after 3 months it's broken down to minimum protection levels. 5,000 miles is under simple driving condation, oil is hot and run a min of 10 miles not stop's no traffic and no hopping on it.

I run only Moble 1 full sin and been thinking about trying RP.

 

your wasting it then, synthetic should be able to go 15k

 

Nooo..I ain't wasting it. I'm treating my engine better than most ppl do.

 

Did you guys notice any improvement in MPG by switching to Synthetic?

 

I put it in right after my first 5k so I would not know. What I can tell you I saw a test with RP and they put it in a 01 GT in the engen trans and rear end and it picked up 10hp and it was not done by RP.

 

how bout when the oil looks real dirty? j/k just bout every 2 mo. or 3k max...I'm using RP for the first time. After the change a buddy of mine says RP burns up.

 

Every 4 months, or 2,500-3k miles. Its a habit.

 

With conventional oils, between 2,500 and 3,000 miles with a new filter. Every 4,000 to 5,000 miles with synthetic. I run 5w-30 Royal Purple and simply change my oil twice a year. Always use a premium filter with synthetic oil. Try Royal Purple tranny and rearend fluids also, good stuff!