Jeep Wrangler Oil Analysis
The same day I changed the oil in my Duramax Colorado, I changed the oil in my wife’s 2014 Jeep Wrangler Sahara. It had just over 9000 miles on the oil, including a 5000+ mile cross-country trip we took for our honeymoon where we drove from the Detroit area all the way to Las Vegas, and then back up through the northern half of the country, through the Upper Peninsula of Michigan and back home.
I’m using the last of the Amsoil Signature Series that we have left from before it was reformulated. So with that in mind, I’ve very pleased with the results. It surely seems to confirm that the oil is safe to use until 15,000 miles without oil analysis.
The metal levels all look good and TBN (Total Base Number) is still at 5.2, which is roughly 40% considering Amsoil Signature Series starts with a TBN of around 12-13. I’ll give it about 12k on the next oil change and see how it looks.
So what is TBN? If you recall the ph scale from chemistry class, TBN will make more sense. TBN is a measure of alkalinity of the oil. It is NOT the same as measuring ph, as a typical ph measurement requires water be present. And while water may in fact be present in oil (hopefully only due to condensation as opposed to a leak allowing coolant to mix with the oil), it is not the main component. Regardless, a high TBN means the oil is more alkaline than acidic. As the oil ages and is contaminated with water, combustion blow-by gasses, etc. it becomes acidic.
When the TBN approaches or drops below 1, it’s time to change the oil. The starting TBN of an oil, and the rate at which it drops is dependent first and foremost on the health of the engine - even the best oil money can buy won’t last if your piston rings are shot and head gaskets are leaking. Aside from that, the quality of the additive package and the amount of additives are what determine how long the oil will last.
Premium synthetic base oils lubricate so much better than convention oil that a larger percentage of additives can be used and still maintain the lubricating properties while increasing film strength, stabilizing the viscosity at both low and high temperatures, and dealing with contaminants.
Amsoil does a great job at blending quality additive packages with quality base oils, which I why I use Amsoil exclusively in my vehicles and also why I am an Independent Amsoil Dealer.
Without further adieu, here’s the UOA:
If I haven’t mentioned it before, feedback is welcome. Please comment and please correct me if I’ve made an incorrect statement - while I do have a degree in Automotive Technology, I’m an IT Professional by trade so I don’t have the time to stay up to date on all the current technologies.
Originally published on MidMichigan Oil LLC, independent AMSOIL dealer, restored from archive.