Tom:
Thanks for the great reply. There are several points you brought up that I’d like to address.
I’m merely questioning the benefits of synthetics, in applications where the OEM did not originally recommend the use of synthetic oil. As for service intervals, I’m questioning the advantages of synthetic oil compared to conventional oil, provided that both oils are drained per OEM drain intervals, which can be as low as 2000 miles to as high as 12000 miles in some cases.
The benefits you discussed regarding oil breakdown are certainly valid, at high temperatures. This is the exact reason why GM recommends the usage of and factory fills their track ready models with synthetic oil. And GM also recommends the usage of synthetic oil in extremely cold climates for the improved cold temperature performance. However, for Joe Blow, how can he realize the benefit of synthetic oil under daily driving conditions? Will his oil temperatures ever reach the point where there’d be a clear benefit between conventional and synthetic oils? Will the minimal deposits he accumulates, from his occasional spike of oil temperature, if any, be seriously detrimental to his engine and significantly reduce his engine life?
Back to the fuel efficiency argument. I do not deny the benefits you stated. Synthetic oils do have a more linear viscosity and should, theoretically, give better fuel efficiency at lower temperatures. Aside from those who reside in sub-zero climates, where synthetic oil is highly recommended by OEMs already, for the rest of us, are the fuel efficiency improvements noticeable? Or are they so miniscule that they can easily be lost by other uncontrollable variables?
Please expand on your “better” additive system regarding synthetic oils. I suppose that its possible for synthetic oils to contain a better additive package, but to what extent? Doesn’t the API already set fairly tight limits on the amounts of the primary anti-wear additives? Will Joe Blow see a realized benefit compared to draining his conventional oil at the OEM prescribed service interval?
You also mention owners keeping their vehicles beyond 100k miles. I can think of many cars that I know of, right now, that have well over 200k miles, some even 300k miles, running on the recommended 5w30 oil and generic filters, and the oil wasn’t always replaced on time either.
Lastly, I think this discussion will be greatly affected if we do not stand on the same page regarding service intervals. I’m comparing synthetic to conventional oils, provided that both are drained at OEM specified intervals. In other words, synthetic oils shouldn’t be providing a cost advantage here, it’s all about the benefits.
But the feel good factor is certainly legitimate. That’s the motive for many of our actions in life, isn’t it?
Great discussion nonetheless, Tom, and thanks!
Thatwouldbegreat:
Saturn 1.9L engines work fine with conventional oil. On SaturnFans, we have many Saturn 1.9L SOHC and DOHC motors in excess of over 200,000 miles running on 5w30 dino and generic filters. Some even have over 300,000 or 400,000 miles. The key is to change the oil and filter at the recommended service interval and keep the oil topped up…which is extremely important on Saturn 1.9L engines as they burn ungodly amounts of oil.
The Toyota 3.0L V6 engines have never had sludge problems if the oil was changed on time. They were exceptionally vulnerable to owner negligence so it was adamant that the oil be done every 5k miles, or less. My selling dealers have yet to have a single case of oil problems with the 3.0L Toyota when the oil/filter were changed every 5k miles.