You are being paranoid. The car is fine, especially sticking with the conservative OCI under warranty. It was a bit silly to expect synthetic oil changes with the comps unless its expressly noted.

Nothing wrong with going back and forth between oils. Nothing. Car will run fine, no damage is done, especially using a 3K mile OCI.

The only thing I would be a bit miffed on is the use of 5/20 vs 5/30.

5/20 is common in the US to squeeze out a tad more MPG, but also a bit on the thin side. For a car that runs a bit warm, I prefer 5/30 or 5/40 if you are in the correct temperature range. Would not surprise me to hear you are consuming more 5/20 then 5/30 either. Not uncommon.

I personally bring my own Pennzoil Ultra to the dealer for my oil changes. Less expensive then the Ester and runs smooth for me. You do the same and the labor and filter should be free as part of your package.

- b

We've been using Redline 5/30, which is both synthetic and ester. No problems at all. Temperature never gets above 230.

This.

I use Pennzoil Ultra as well and just pay to have the oil change done, which is like 25 bucks or something. They use their oil filter so the total cost is like 50 dollars including the oil for a full synthetic oil change which I change yearly (I don't drive it during winter months)

My Nissan part guy told me that the only synthetic oil that Nissan reccomnds is PENNZOIL® PLATINUM™FULL SYNTHETIC MOTOR OIL

B/c is has ester oil in it ,I didn't check to see if it does but I use it.:tup: