RVM:
"Hmm... so what I'm gathering from this thread and from reading lots of other threads is that synthetic provides no lubrication or protection benefit over dino oils unless you are looking for longer OCIs. Therefore, the only advantage to using a synthetic is a longer OCI?"
There are some exceptions, and certainly good synthetics have superior properties to good dinos. Better flow when cold, better resistance to heat, less shearing, and the list goes on. Unless you are doing something out of the ordinary with your engine, though, it just doesn't seem to matter: the actual wear is every bit as good with dinos. I find Havoline and M1 to be equivalent and excellent when looking at UOAs in a wide variety of instances, although noise and consumption are often seen to be higher with M1.
But again, if you see extreme heat in your engine, or extreme cold starts, or extreme revs or if the engine is highly modified, synth would seem justified. Also if you need to run synth because of particular manufacturer specs.
I'm going to try Redline in my wife's car next change, and a long OCI. That way I just won't have to worry about it for a long time, and with a good discount Redline's beefy add pack and keep-it-clean ester base is worth the premium over increasingly pricey M1. My car, which I want to keep running "forever," is going to get a Hav/Delo mix.
MHO.
- Glenn