Originally Posted By: Clevy
How does that work?
If 2 oils are certified for use in this engine then they should perform in a similar fashion,otherwise why certify an oil.
Oem's certify lubricants for that very reason,so they perform up to the manufacturers expectations or how exactly are they supposed to set intervals and guarantee engine performance and longevity.
Uncertified or "suitable for" suggestions don't cut it and I can understand if they somehow don't live up to an oem's set standards however if your saying an oem certified product won't perform as expected as far as oil change interval or whatever else then what's the point of getting certified.
I don't get it. If the oem guarantees their equipment and sets a standard then certifies the lube and the lube underperforms who exactly is at fault?
Doesn't make sense to me.
It is one of those quirks in life that are somewhat unaccountable for. I have found over the years, that engines and oils are a lot like small caliber rifles and ammunition.
I can take two really well made, name brand rifles and feed them both the same quality name brand ammo. I will get different groupings. I can then take another quality name brand ammo and try it again, and get totally opposite results. Doesn't mean the rifles or the ammo are inferior. Only that based on minor variations, there is a difference in the result. I can even show the same thing when taking two models of the same rifle from the same manufacturer. Ask anyone that deals with firearms on more than a casual basis snd they can confirm this.
Delo 400LE 15w40 is certified and approved by Detroit for my 12.7 engine. But the result was that the oil was screaming for mercy, according to the UOA's, in short order. Whereas, the Schaeffer 15w40, not on the approved list, is doing quite nicely in the same engine for even longer OCI's. I had a similar situation between Rotella and Mystik in my previous Cummins ISX. The Rotella was really beaten up by my ISX, whereas the Mystik did a stellar job.
Let's take the 5.3L in my Chevy pickup. Many folks, using dexos approved oils, have experienced excessive oil consumption issues. Some attribute it to the AFM function of the engines or some other issue, and I doubt it is the result of poor oil quality. My 5.3L has been on a non-dexos 5w30 synthetic and it only "uses" about 8 oz of oil in 7000 miles. And of that, the PCV oil catch can I have on it has captures about 6 oz. The engine has really only "uses" 2 oz in 7000 miles and runs great. And UOA doesn't show that there is an issue using this non-dexos "approved" oil.
Then there is the 2.8L VM diesel in my Jeep Liberty. Using Mobil 1 0w40 as per the owner's manual recommendation, the results were not as good as using CJ-4 5w40 synthetic in it that I switched to. Better UOA's and the engine has not experienced some of the issues that others have seen, based on this model on forums elsewhere. Does that mean the Mobil 1 0w40 is an inferior oil or that the OEM was full of buffalo bagels? Hardly. It only shows what we experience in many parts of life... that some things don't play out quite as nicely as we think they should in real world conditions.
That is why I stated that OEM recommendations are guidelines. They are simply starting points to work from. In many situations, they are good and all that is needed. In some situations, not so much. No two engines are operated exactly the same or perfectly matched in every internal detail, etc.