f150crewcab

I've only used conventional oil in my '02 F150 Crew 4x4 (4.6L). I bought it used and it now has 93K miles. I've read about the advantages of synthetics, but also of the risks of switching on "older" models (7+ years or over 90K miles), particularly to the various gaskets coming apart. So, it makes me think a syn blend might be more appropriate or should I stick with conventional oils? Thoughts? Thanks.

lazar20

I would go with synthetic, even at 90k. I switched from conventional oil and I love the longer time between oil changes.

f150crewcab

...I've even read in this forum that I should use an engine cleaner, such as http://www.auto-rx.com/ before switching....

redneck2725

I only use Amsoil, and will be switching at my next change to their synthetic

Kattumaram

Oil base stocks whether natural or synthetic are fully compatible with one another; there will be some variations in additive packages, however.

Of the last four vehicles I have owned, and I still have two, all had in excess of 100K miles when I bought them and all of them had natural base-stock oils in them. I switched all of them over to full synthetic, specifically Wal-Mart Supertech 10W30, with no issues whatsoever. In fact, oil control in two of the vehicles improved with the use of Supertech due to the seal conditioner included in the additive package.

Synthetic oils generally last a bit longer than naturals primarily due to improved shear and temperature stability, but the key to longevity of oil service is the additive package; they all become exhausted and the oil must go b'ye b'ye. The king-of-the-hill for service longevity must be awarded to fleet service oils such as those used in over-the-road diesel articulated lorries. (Articulated lorries....I like that Brit term for a semi.)

I would be rather nervous about running 10K miles or more between oil changes unless I was using Shell Rotella T 5W40 full synthetic or equivalent fleet service oil.

Firehawk951

You should ONLY USE Motorcraft its a blend and its made by ford for ford how much common sense is that it even says in your manual and under your hood....