Floyd2004 said:
If the Jeep has has ANY conventional oil in it then you are doomed to that and that only. Going from Conventional to syn. will break down most of your seals mush faster.
BUT if the previous owner used Full Syn. (stock for any DCX vehicle) then keep on using it. I Use full syn. and change it out every 5-7k with no issues. Its an 04' with 53k on the dial
.
Not true, you can switch back and forth and even mix syn with dino without any repercussions..
The biggest benefit to Syn is it sheds heat much better then dino, your jeep will run cooler, and it's the one reason Syn lasts longer.
As far as oil changes, WHO started the suggestion of oil changes every 3,000 miles? When I bought my first car they suggested between 5 - 6,000 miles, oil only, and every other change the filter. Now the oil companies are selling twice as much oil, and telling you to change the filter at EVERY oil change, yet there is test data out there with full synthetic showing NO breakdown in viscosity after 50,000 miles.. Mecedes got in trouble because they were running Synthetic in their cars, and the owners manual said Oil Change Interval 50,000 miles, so dipstick consumer would put in regular Dino, and try to go the 50,000 miles THEN sue Mercedes because their car brokedown.
AIR, I would go with full synthetic, it's worth the extra money in my book, especially if you are doing the oil change yourself.