OK, guys. Got a question, but, first the Reader's Digest history. Tiny's been with me since she only had 38 miles on the odometer. Now past 240K. Vast majority of those miles were with either Delo400 15w40 or Rotella 15w40. Figured that's plenty good enough break-in, so went with Rotella synthetic 5w40 on most recent change, having read that "sythetic's good for the seals" and etc etc etc.

The question is two-fold: First, if the seals did shrink a bit using "old-fashioned" oil, will the synthetic re-swell them?

Two, if so, how many thousand miles should that take?

 

no real "time limit" but the synthetic oil is more slippery and the molecules of the oil are infact smaller that petrol based oils.... if its your front seal its easier than it looks ... it seems intimidating ... pull shroud, pull fan, pull balancer and pull front cover.. real easy if you have the tools and time.....
if its the rear seal take to good local shop ....

the synthetic is much better in its all .... i have gained 2 mpg's with just changing my oil .... now running Royal purple 15/40 and Z-max ... and lovin the mpg's

 

Seems to be the front seal, and the drippage seems to be slowing down a little. But, I'm in an apartment, now, and parking-lot wrenching is frowned-upon, especially to that degree. Frankly, I figure a little bit of under-body oil-spray while driving down the road might annoy the guy behind me, but, would provide a good layer of redneck rustproofing.

 

its said that if you go from non synthetic to synthetic is can wear away worse might want to be careful usually on a truck with that many miles i would run just regular whatever you want for oil i would stay away from synthetic what ive heard in school and from multiple people is synthetic after non synthetic for that long can wear away old oil causing problems

 

Wouldn't surprise me. I do everything the hard way