This is a frequently recurring question. I think maybe we can answer it here.
In respects to the cleaning and rinse phases of Auto-Rx use.
Synthetics:
SOME synthetics contain components that will inhibit/slow Auto-Rx's performance.
Mobil 1 Amsoil (except XL line) Royal Purple Redline Castrol 0w-30
These oils contian either esters or di-esters or other complex components that will not give optimum results. They're VERY expensive to be using for the limited mileage of Auto-Rx treatments. If you REQUIRE a synthetic, then Rotella T 5w-40 should satisfy your needs. There are also plenty of other synthetic products that are not on that exclusion list. That list is not all inclusive, but covers all the over the counter offerings. Please don't ask about Fuchs, Elf, LubroMoly, Motul or any of the other obscure formulas from niche blenders. Just don't use them for THIS SMALL SEGMENT OF YOUR ENGINE'S LIFE. For the limited mileage that the sump will be in use, MANY MANY OILS will work just fine. Euro-alloy owners. Some of you may object that the approved oils are not on the list. Those approvals have terms and conditions attached to them that you are not going to ask of your Auto-Rx treatment oil. You're not going to require a fuel economy standard with a durability standard along with all the other hurdles that the later date OEM's require from oils. It has nothing to do with suitability for use in a safe and effective manner.
High Mileage Oils (IN ANY FORM CONVENTIONAL OR SYNTHETIC)
These are verboten. DO NOT USE HIGH MILEAGE OILS WITH AUTO-RX. DO NOT USE HIGH MILEAGE OILS WITH AUTO-RX. DO NOT USE HIGH MILEAGE OILS WITH AUTO-RX.
These contain seal swelling and seal softening agents that will be counter productive and can indeed exacerbate your condition and even damage an otherwise restorable seal.
Did I fail to mention: DO NOT USE HIGH MILEAGE OILS WITH AUTO-RX.
After the treatment HM Oils should be unnecessary.
Please use conventional oil whenever possible. It's cheaper for the limited mileage it will be in use. It will give you the best results in a predictible manner.
EUROPEAN USERS WHO ARE ACTUALLY IN EUROPE: YOU CANNOT USE SYNTHETIC OILS. USE SEMI-SNYTHETIC OILS. European standards to not allow Group III oils to be called SYNTHETIC. If it's a full synthetic under European standards. DO NOT USE IT.
Once clean, you may use the maintenance dose with any oil.
-- Edited by geeaea on Saturday 4th of December 2010 03:32:18 AM
-- Edited by geeaea on Friday 28th of January 2011 03:16:44 AM
-- Edited by geeaea on Friday 28th of January 2011 03:17:40 AM
-- Edited by geeaea on Saturday 2nd of April 2011 01:55:46 AM
