How often should one change synthetic oil? I understand it's not like conventional oil " 3 months or 3,000 miles.

Thinking of switching over to royal purple or mobil 1.

 

3 mo/3K miles is silly. Today's conventional oils, under average driving conditions, can still provide engine protection beyond 5K miles.

Synthetic oil should be changed when the oil analysis says it is due. That means that you have to have it tested periodically. Since all but a few diligent owners are too lazy or cheap to do this, most run it until they think it needs it (they're usually wrong), then change it. FWIW, the synthetic oil usually doesn't wear out, but the additive pack gets depleted.

Steve

 

Changing over to a synthetic now may not be wise. Of the two oils you mentioned, both are a PAO basestock oil. These types of synthetics will have esters (M1 will be a fatty acid ester) that naturally clean an engine. Your 1999 Triton should have somewhere around 90,000 miles on the engine, if the truck is an average driver. The engine may not be leaking now as a little sludge or varnish is keeping it from leaking. The synthetic oils are going to clean this up and leaks are likely. I wouldn't do it if it were my engine especially considering the HOT San Antonio weather. I would use a quality dino oil like Havoline, Chevron Supreme, or Pennzoil and change at every 5,000 miles. The Triton engines are pretty clean burning engines and oil contamination is not nearly the issue of the older engines. Oil changes at 3,000 miles are a waste of money and resources.

 

I've used Royal Purple with K&N filters for about 5yrs now....I usually change oil every 5-6k...I feel it improves the trucks h/p and mpg by about 1-2 miles....I really like it....

 

I also use Royal Purple oil. I think it is one of the best out there! And no you don't have to get a oil oil analysi just change it around 7500 miles. You are going to get better gas mileage too!

 

i run the 15,000 mile oil and i just change it when it needs it... checking the color and the way the motor acts with it.

 

royal purple is my trucks blood Makes my truck feel like the Corvette of all trucks