I had to dig up some old details, but here's the data from my compression testing experimenting with ARX.
Here's the background info ... Taurus 3.0L Vulcan engine. The engine overheated because the front passenger-side freeze plug rotted out and there was an immediate release of cooling system pressure and much of the coolant. As you can see from the chart and image, the freeze plug was located between cyls 4 and 5; hence the greatest heat concentration affected those two cylinders. Whereas those two cylinders had almost no coolant, I suspect there was some residual coolant in the back bank, as they were not nearly as badly affected.
A neighbor (elderly woman) was driving it at the time and continued to drive home several miles after the engine lost coolant at a stoplight. (Yes - she should have pulled over and shut it down, but she didn't ... ). So while the engine didn't seize, it did suffer severe heat localization and several of the rings packs coked up hard, because while it "
drove fine" on the way home (according to the woman), the oil didn't really get cooked to a carbonized goo until she parked it in the garage and the oil just baked in the ring pack. As you can see from the data, the initial compression readings showed some cylinders with slight sealing problems, and two cylinders with significant problems.
The experiment was done back in 2008, IIRC ...
* Conventional oil base stocks (no syns used).
* Compression checked at the start of each step in the trial.
* Compression rounded to the nearest 5psi increment
- First trial cleaning phase used 2 bottles of ARX in one application (it's noted in the chart as "2app" to indicate two-times the dosage). (1k miles duration)
- Then a rinse phase. (2k miles duration)
- Then a second cleaning phase using only 1 bottle of ARX. (2.5k miles duration)
- Then another rinse phase. (2.5k miles duration)
- Then a final compression check.
As you can see in the chart, without any doubt, the rings were stuck quite badly in cylinders 4 and 5. But after two full cycles of ARX (double dose; rinse; single dose; rinse), the rings were fully liberated. It can't be a bad thing to have full compression with clean engine internals! Rings which can freely float in their lands are always better at controlling the oil film, and maximizing compression for good efficiency.
