Originally Posted By: ARB1977
I don't see myself going 10K on conventional oil in the V. Even at six months the OLM is at 30% 9-10K miles.
Wow. What exactly do you know that the oem doesn't to necessitate not following instructions.
As far as syn vs conventional unless the engine has a turbo or something specific that makes it hard on oil or its rings are well worn causing excessive blow-by any API conventional can do a 5000 mile interval,and it better be able to do at least that or its junk and move on. Special circumstances excluded.
Now as far as synthetic goes if the oil cannot do a 10000 mile interval or more then its not cost effective to use it over a conventional unless bought at a reduced rate.
Its all about money. If syn costs double you gotta run it twice as long or your wasting money. In regular service I have yet to see absolute proof that a syn protects better and will lead to longer engine life vs a conventional changed at proper intervals.
Syns last longer in service,they do offer advantages that most engines will never require,so using a syn and changing it at 5000 miles is retarded(special circumstances excluded). There is absolutely no gain.
I'll bet a jug of your favorite oil that if you got 2 used oil analysis,both at a 5000 mile interval the wear metals would be so close they would be indistinguishable from each other and you wouldn't be able to tell which oil was which.
Now with that said I use syns because I do the math. If syn on sale is within a few dollars as the conventionals regular price then its a smart buy because the value,and mileage increases double for the same price vs using conventional for less miles.
And just to put it out there. Dnewton is running 10000 mile oil change intervals using conventional super tech oil and his used oil analysis' are showing average wear numbers per mile driven when compared to the data he has collected,so even a 5000 mile oil change interval is conservative and not likely pushing the limits of an API certified conventional(special circumstances excluded)
Its all about value. Return per dollar spent,or dollar not spent to achieve a given set of parameters.
Early oil changes are actually shown to increase wear metals at the beginning of the change interval because the new oil strips the anti-wear layer off the parts which increases wear metals until the new oil applies it own anti-wear layer,then wear metals trend downwards.
So in reality the longer you can leave the oil in,without depleting tbn is the ideal time to change oil. That's where used oil analysis are a valuable tool. Use the same oil and have it tested for 3 runs and follow the labs instructions. Then you are getting the most from the oil without running any risk of tbn exhaustion. Then you also decrease the anti-wear layer stripping and re-application thereby reducing wear metals per mile driven.
K. Novel ended.