Your low oil pressure warning light can come on for a variety of reasons. One being a high level of sludge like deposits blocking the oil pick up screen. It could also be that the oil sending unit sensor that triggers the warning light is faulty or dirty giving a false read. If you are no longer driving the car, then Auto-Rx can not help you. Auto-Rx uses the running motor to circulate the product through the system dissolving sludge deposits. So if your decision is not to drive the car due to the warning light, then your only option would be to drop the pan and clean it as well as the pick-up screen and tube.
If you decide to run Auto-Rx, I would wait until your next oil change and run a group III oil or conventional oil during the ARX cleaning and rinse process. Auto-Rx does not work as well with group IV full synthetic oils. So first run your M1 0w40 for 3000 miles and change out before running ARX. At least you will have gotten some monies worth out of the M1, you recently installed. Then I would read up on the heavy sludge application on the Auto-Rx web site. You will need to run two applications of Auto-Rx in the cleaning and rinse mode, changing out filters at the half way point in mileage during the first application.
Perhaps another solution for you is to have a mechanic, test the oil pressure in the motor with a mechanical gauge, just to see if you truly do have low oil pressure. If the oil pressure is within range and your only problem is a dirty oil sending unit sensor. If it just the sending unit, then you should feel free to drive the car, without any likely failure in the motor.
When the light comes on, does the motor make any different sounds? Like noisy or ticking sounds coming from the valve train? Many folks have been successful running ARX to clean up the sending unit and clean up motors like yours. I cant tell if your oil pressure is very low from here. If it is infact very low, I would spend the money on the pan drop and manual clean. If it is verified to be within range, then do the ARX treatments, after using up the M1.
Hope this advise is helpful. Please feel free to ask more questions you may have.
Since it wasn't mentioned let me point out that "if" the owner finds they in fact do have a sludge problem the PCV system should be serviced as well. A time consuming process but one that needs to be done on a regular basis regardless of any sludge issues. If you don't service the PCV system and it becomes plugged you will have sludge issues. If you have sludge and a clogged PCV system the sludge will return faster than you can remove it.
Having the actual oil pressure reading for reference is excellent advise. Not just at idle but for through out the entire rpm range. If it is necessary to clean out the oil pump pick-up screen I would start using ARX as soon as possible.
