I have been using Amsoil (www.amsoil.com
) for 21 years. My parents used it many years before that. Back then they had 25000 mile oil changes and change the filter every 12500 miles, or 6 months, whichever comes first. We usually always ended up with over 150,000 miles on our vehicles. We drove them till too many things started going wrong. Never did we have a problem with the engines or drivetrain.
Synthetics DO NOT break down. They get dirty. If you can remove the dirt, you can run the oil for hundreds of thousands of miles(people have done this). The amsoil filters are the best oil filters made, they filter out smaller particles of dirt than any others. Hastings filters are #2 for dirt removal. With Amsoils Oil Filtration Bypass system, you can run your oil for tens of thousands of miles. You just send in a sample of your oil every 3000 miles for analisis and you can tell before things start happening to your engine.
Also, if your running a true synthetic, you do not need to add additives to them.
The syntetics oils can have more dirt in them and continue to lubricate. That is the primary job of oil. Secondary is cooling. But, with the synthetics being able to keep lubricating longer with more dirt in the oil is where a lot of the extended oil changes come from.
With good filters, you can get this dirt out of the oil, and therefor cause less wear.
If you follow the oil manufactures reccomendations for changing the oil, you should be safe.
I have used Amsoil because it is the BEST oil out there.
I do know that running Amsoil at its recommended intervals will not void the warranty. If you get a Dealer that tries to tell you diffrently, just contact Amsoil and they will set them straight. There have been a few court cases in the past that also set presidence.
I know I will hear flak from this post, but, It would't be the first and it won't be the last.
Oh, and Amsoil also makes a 7500 mile oil that I beleive is a semi synthetic for those that don't want to think about going 35000 miles on a oil change.
I have not currently put it in my AV, but will as soon as I change the oil. I do have it in my Dodge Grand Caravan (124,000 miles on that) Engine, Tranny, Differential. The MPG on it increased about 20% when we did that. We run about 22 - 23 mpg avg now and were around 18 - 19 before. And I have it in my Corvette.
Most people would never try to run there oil for 35,000 miles because of uneducated and misinformation. I DO know that Amsoil used to have a guarantee that there oil would not cause your engine failure. Not sure if they still do though.
I have used amsoil for many years and many miles and have had no problems with it.
Oh, I also had an instance where my dad went about 75000 miles without an oil change on a Chevrolet Celebrity. as soon as I found that out I took the car and had the oil changed. It was the Blackest oil I have ever seen. it was nasty. But, we ended up putting another 75000 miles on it after that before we gave it to the Kidney foundation or something like that.
Amsoil doesn't just make oil either, they also have tons of other car care lubricants and cleaners.
I just ask you to go to there web site and take a look around.