[ericpeterman]

V6 isn't as critical regarding sludge formation (no turbo). OTOH, any engine will benefit from a thorough cleanup, even one with only 40k on it. I'd hit it with Auto-RX and then (ideally) maintain perfect cleanliness with a maint dose of 3 oz every change, or at least do a clean every 30k or so.

I wish very much that I'd known a couple years ago what I know now about oil, sludge and engine cleanliness.

 

[ericpeterman]

Maint dose of 3oz is fine with synth per Frank and Tony. Dino is called for only during rinse phase after full cleaning. The idea of maint dose is not to clean and then rinse off big deposits, but to maintain cleanliness attained with the clean/rinse and it works fine with synth. The chemistry and demand on oil and detergents of a dirty and sludged engine is very different from that of a clean engine, IOW and cleanliness allows the maint dose to do it's work.

If you've not run the clean/rinse don't try the maint dose.