Originally Posted By: AgingChuck
OVERK1LL, Pablo: This is the problem with knowing the nitty gritty on each oil. It is almost impossible to know which oil is the best for what application or which oil will or will not be a point of contention IF a problem occurs. One could use an inferior oil just to meet a manufacturers warranty quidelines but perhaps hurt the longivity of an engine long term. However, I would say that any appropriate oil, changed within mileage limits would work well. I have driven many vehicles way over 100,000 miles on oils that were not top tier. I don't think oil is a major issue of engine failure if changed on a regular schedule. That being said, I do want the best oil I can for a given usage..
This is how it worked when I worked at a dealer and how I have always understood it.
API Certification is a MUST for new car mfg's when called for. Not just meets/exceeds. It better actually be certified or it is an issue.
For the car mfg's own oil spec it is generally accepted that an oil just needs to meet/exceed it and not actually be licensed. Now, being licensed means you won't be asked to prove it meets/exceeds the spec BUT it is not required. If a problem occurs wiith a non licensed oil you just proivide the data from the oil mfg showing it meets/exceeds the OEM oil spec and you are good.
I have had more than one rep from new car mfg's say this to me( I worked in the auto field for many years both dealer and aftermarket and dealt with a lot of car mfg's ). API is an independant organization and thus a car mfg can require certification with no Magnuson-Moss ramifications. If they required that you only use oils licensed to meet their own oil spec it falls into the Magnuson-Moss act area dealing with a car mfg can not require you to only use OE parts unless they provide them for free.
Regardless of where the truth actually falls the bottom line for as long as I have been into auto's is API is a must but meets/exceeds works for the OE oil spec when it comes to warranty. You also need to use the correct viscosity and change it within the max allowed for time interval.