Hi XXXX,I dont know what reviews you have been reading. But to say that Auto-Rx does not clean deposits off of aluminum is ridiculous. All pistons are aluminum for the most part. Auto-Rx cleans the lands of the pistons freeing up piston rings all day long. Almost all motors in passenger cars and light trucks produced today are aluminum. Granted many have steel sleeves in the cylinder bores, but nearly all have aluminum heads. Auto-rx does not see the difference between an aluminum surface and a ferrous metal one. It is designed to work on the deposits formed on either surface. A good deal of the actual critical working parts such as cam lobes and bearings are still steel.
I would applaud that you run a high quality motor oil such as Castrol Edge. Many folks think that it is a better overall product than the gold standard Mobil 1. That is actually a good debate. And one would think that if both oils are so fantastic, there wouldnt be a need for a product such as Auto-Rx. But this is very much untrue. A good majority of Auto-Rx users have encountered sludging in their motors running top tier group IV full synthetic motor oils. This is likely due to a false security of running extended drains. Or even in some cases whereby the car manufacturer has suggested oil change intervals that were just too long in the real world. I guess it is human nature. But there is a huge difference between running 7500 miles on the highway over a 3 or 4 month period and driving 7500 miles on short trip city driving over 12 to 15 months. I guess you can guess that the later description was not conducive to the 7500 mile oil change interval. Most consumers dont realize that driving conditions play a huge roll. The other thing we find with most folks running into sludge issues is the lack of PCV valve or crankcase ventilation service. It is imperative that the crankcase be able to release not only combustion gases that enter the cavity from blow by, but also the moisture drawn into the motor from air conditions. Otherwise the catalyst for sludge formation is in place and it doesnt matter what oil you choose to run.
With respect to cleaning existing deposits in a motor, it needs to be done safely. By safely I mean no interruption in lubricity, and also done in a controlled rate whereby the deposits are dissolved and not shocked off surfaces in larger than desirable particulates, which can cause more harm than good. Auto-Rx is designed to do just that. That is to provide enhanced lubrication and clean in a controlled methodical matter. By methodical I mean work to get the actual working components clean first. This is predicated by the oiling system which is where the oil is directed towards with the most flow. Auto-Rx works with the oil to clean working parts or frictional surfaces first. At the end of day these are the critical parts of engine longevity and good working performance.
However, the cleaning should be done in responsible manner. For instance, the oil is going to get dirty much faster running Auto-Rx than by simply running a new oil change alone. We have proved through used oil analysis that the product can be run for 3000 miles in dirty motors without causing any higher rate of wear metals. But it should be logical to a consumer that you really dont want to run dirty oil any longer than you have to. Simply stated there are wear metals lodged in sludge deposits. As sludge is dissolved these wear metals are released. Granted they are quite fine in mass, but it is normally wear metals circulating that create more wear. Harder wear metals will create wear on softer metals. Such as steel trumps aluminum or copper. So we normally suggest running a conventional or group III motor oil which is highly refined conventional oil for auto-rx use. I notice that you are an Edge fan, which is good. But over a 3000 mile oil run I would offer that Castrol GTX will provide as good of engine lubrication and protection that the Edge product would offer. The Edge would cost likely 30% more to run for 3000 miles. Also, we find that Auto-Rx is more active on critical engine components in an oil that has mineral oil as its base. Group IV synthetic oils which are either ester based or use PAO(polyalkylolefin) as their base slow down the cleaning action of Auto-Rx. PAO oils do not accept the oil companies desirable additive packages, without the help of coupling ester to hold the additive package in suspension.
The level of these coupling esters can be quite substantial. In an ideal world Auto-Rx which is all esters in composition works best when it is either the only or at least the dominant ester in the oiling mix. Esters are polar in nature, that is they typically have an attraction to metal surfaces. So the cleaning ester of Auto-Rx are somewhat forced to compete with the polar properties of the esters in group IV full synthetic motor oils. Which is why we recommend running the Auto-Rx longer in full synthetic motor oils.
But why would you choose to run with an expensive full synthetic for the Auto-Rx application when a mineral oil based product will provide the same level of lubricity over a 3000 mile run? And why would you want to run a rinse phase on a polar motor oil when the whole idea is to get contaminants to release from metal surfaces.
I hope this helps you with regards to your application.
