I scanned pretty quick through this thread, but if hasnt been mentioned already, with 9*,000 miles on yer truck, it probably wouldnt be a bad idea to switch to synthetic no matter what...

 

Just thinking long term. I want to keep the engine going another 90k miles, so, just trying to take care of my baby (truck).

 

As long as it isn't leaking/burning, the lighter weight oil shouldn't cause any problems.

 

EXACTLY! I switched to full synthetic (RP) right at 100k ran great before and runs even better now! Just make sure you don't have ANY oil leaks and you don't use any if not then you should be good to go.

 

If you switch to a lighter weight oil, just check your oil regularly the first oil change to make sure you aren't burning any. You don't have the 5.9L so you'll be fine. Those are notorious for burning oil. Well, everyone i have seen has been low on oil and/or puffing smoke on start up.

 

Has anyone tried the new Castrol Edge Synthetic? Its the same price as the RP.

 

^Haven't tried it yet. I also switched to synthetic (Royal Purple as well) and it is well worth the extra expense. The engine feels like it runs smoother and responds better. Plus, synthetic allows you more time between oil changes.

 

older engines can leak if you switch to synthetic the molecules in the oil are smaller

 

If you have leaks now then they just get worse later, tighten the bolts or change out gaskets. I remember when Syn first came out people were saying thjey had leaks but I never knew of anyone personally who had it. Mine doesnt leak.

 

No leaks at all.... Hum, i got knowledge & opinions here, well, got to think this one over....