Here's what we recommended to one user who had a known sludge condition who emailed us with some questions. Please note the terms and conditions involved.
I am preparing to use AutoRX, using supertech, which I purchased from
walmart as you have recommended.
Both the Mobil M1 102 and the Mobil M1 209 will fit my RX300.
Do you have an opinion as to whether It would be beneficial to use the 209
which is larger and might hold more sludge and continue to be functional for
the first part of the cleaning cycle?
Would appreciate your valued opinion.
If you suspect or have confirmed sludge, I would use cheaper filters and change them out prematurely. If you think about it, if the sludge is of enough physical mass it would fill the entire can. The oil will suspend so much material with its detergent and dispersant package and the filter will have a given holding capacity.
Let me try and communicate this. OEM spec'd filter, and all filters for that matter, are insoluble collectors. They limit the size of the combustion byproducts that circulate in the oil. Some can be quite large. Most of them are created during the fuel enrichment process. This is why you always see a time/mileage component to the OEM recommendations. It assumes a daily drive in which each vehicle will transition through the same fuel enrichment process. Less frequently used vehicles will fall under this umbrella too with the time component.
For a finer filter to just meet the OEM specified time/mileage component, it has to have a proportionally higher holding capacity. The filter (all filters) fatigues over a curve. Advanced medias allow some filters to lower and elongate this curve, but will need even more additional holding capacity to exceed the OEM spec's with the finer spec's that they report for marketing purposes. Those numbers, btw, are how the filter performs at its saturation point. This is where it's holding capacity is measured. Out of the box the performance is not as good. The "nominal" or 50% (Beta 2) rating is more indicative of typical performance.
In short, I don't think you'll be well served spending up to 5 times the cost of a cheaper filter. I would just change out the cheap filter in 500 miles and see if the centerwell has material in it. This will be silt that just settles out. If yes, continue to change filters every 500 miles until it no longer appears. If not, leave the filter on for the remainder of the cleaning phase. If this continues through the entire cleaning phase, continue filter changing for the rinse phase too. ST, MotorCraft, any of the lower tier filters will be fine for this type of use. $2.xx-$3.xx in price. Save the Mobil 1, K&N, PureOne, Bosch Distance Plus for longer drains, or at least the post Auto-Rx treatments.
Under this method you can extend the cleaning and/or rinse phases as long as you're comfortable with the oil you've chosen in the sump. Our limits are set more or less to limit the likely material in suspension. By changing filters in a timely manner, you eliminate that factor. Naturally, top up as need and if you see no material of merit accumulating in the filters, just follow the normal process of 2500-3000 miles cleaning and 3000 miles rinsing.
