If you "think" the oil was fine at 10k, why not run the same oil 12.5k and then send it in? Having "more" TBN at a given mileage does absolutely nothing beneficial for your engine... i.e., if two different oils are used and drained at a hard limit of 12.5k, and one oil has a TBN of 2.3 and one has a TBN of 5.2, all this tells you is that BOTH oils could be used in service for some additional time (as long as viscosity is still in grade). However, TBN does not decline linearly, so even the oil that only had a TBN of 2.3 "may" be sufficient to take out to 15k or more... it all depends on your engine and usage. It's not something you can guess about. Amsoil SS is rated to 25k OCIs, and should certainly get you well past your comfort zone at the very least. From what you're saying (and not saying) in your posts, it sounds to me like you would be almost perfectly served by a nice 5W30 A3/B4 oil. Castrol and Ravenol both make good oils that are in this category that I've used and would recommend. Just remember that picking an oil solely on TBN is like having a chimpanzee pick out your clothes for the day- it may work, but you may end up looking like a monkey. Pick your oil based on the manufacturer's requirements for your engine and go from there.
Originally Posted by camryrolla
Miller, I have not done a 10K UOA, but running AFE/EP at 10K is a walk in the park for this Camry. My goal is to extend OCI further to 12,500 miles, and even to 15K OCI if I could.