I did the engine on my last car, an Acura CLS. Used Blackstone. I wanted to see if Mobil 1 or AMSOil was better for the engine, if AMS was worth the cost. I also had a foam air filter element and wanted get an idea if it worked well.
In the end, I found out Mobil 1 was bad (4 times more wear, shot at 7500 miles), and the foam air filter was good. I changed oil filters at 3750, oil + filter at 7500.
For the 4.0 aluminium owners using Mobil1, I'd get some analysis done. There is no history of how Mobil1 performs in your engine. There are many reports showing the V8 does fine on Mobil1.
I still won't buy/use Mobil1. They have a habit of
changing their formula all the time.
Why?
To cut cost? To improve performance (because the stuff before sucked)?
And whay have 5 different formulas? Marketing BS.
I've never read of AMS, Red Line, and Purple changing their formulas.
My opinion, Mobil1 is driven by the $, supported by marketing. The others HAVE to research and make a good product to survive.
I was also going to monitor the tranny fluid in my last car because of know transmission problems. Had the tranny replaced once. After the ATF fill plug was crossthreaded on the replacement transmisssion, by the dealer, I was so pi$$ed I traded in for the 4Runner before having the fluid sample analyzed.