What is the Best Synthetic Oil? - Best Synthetic Oil Guide
A few points.
1) I tried HARD not to be that Amsoil fan boy by purchaseing most of the top brand oils on the market over the years, but always came back to Amsoil.
2) For me it's the feel of each vehicle with or without Amsoil. I always used Amsoil in this particular vehicle and needed dealer service and without asking me they changed the oil from what I was using to whatever they put in. The vehicle ran like a completely different vehicle. the engine was louder, it vibrated more at highways speed, didn’t seem to idle as smooth etc. I dumped out whatever they put in it and the vehicle ran like it did prior to the dealer putting in their oil.
For me that was an immediate test from morning to the afternoon when I picked it up.
3) I purchased a new vehicle that turned out to be a Lemon. I already changed the oil on this Lemon at 500 miles like I do to all my new vehicles to remove any casting sand. I sued the dealer and the manufacturer for a replacement vehicle. In the mean time I vowed not to spend a dime on this Lemon in repairs or maintainance as I was sure in a few moths I would be getting a new vehicle, that's how good my case was. Well, three years later and 60,000 miles they settled and gave me a new vehicle. I never changed the oil again after that first oil change and the vehcile ran like it was new. The Lemon issue had nothing to do with teh engine.
4) This was on my diesel sprinter. Again always used Amsoil that I brought into the dealer to change when oil changes were due. One time on the road I didn't have the Amsoil so I said change it with Mobil one. Same exact reaction with my other vehicle that was changed from the dealer. It just rand "different" louder, more vibration etc. I did the same thing, once I got home from that trip I dumped out the Mobil one and the vehicle returned to "normal"
5) Last week I changed my Kubota 4060 that has only had Amsoil in it to T6 because of all the raves here on this site. Here we go again. The tractor sounds horrible and just doesn’t feel the same at high revs as before the change.
You guessed it, the Rotella T6 is going to be dumped out this week.
I still have various quarts of Royal purple, Red line, Mobil one, Castrol oil etc in the garage from testing on various vehicles.
I've spent many, many years "experimenting" to find the "perfect" oil and jumping at the chance when "fan boys" tout T6, Mobil one, Royal purple, Lubrication Engineers, Motul, ($18.00 a quart),Schaffer oil, Liquimoly, I've been through them all trying to get away from Amsoil. If the evidence was there for me to use a better oil, I'd do it, heaven knows I'm trying.
If any operator doesn't care or is not as in tune with their vehicle heck just put in the cheapest stuff out there and you will have zero problems as long as you follow the specs of who made the vehicle.
For me, what I spend on oil is protecting something that is worth far, far, more money that the few extra bucks I spend on oil over the stuff you can buy a 7/11.
I don't sell Amsoil, I'm not a dealer, and I could not care less whose name is on the bottle as long as it makes my vehicle run smooth. I'm getting too old to keep "testing" chaeap and or designer oils, 40 years of testing is enough for me.