I figured I'd share this issue that one customer encountered. I've gone about 300 miles since I started the cleaning cycle on my Mazda 626 2.5 liter engine with 115000 miles. It now sounds like the engine is crushing rocks so badly it worries me. Is this normal? What should I do?
Odd noises is not an uncommon side effect of Auto-Rx use. Areas under forced circulation tend to varnish up and restrict as a unit, but cleaning will affect the thinnest layers first. This is most apparent in passenger car engines with hydraulic lash adjusters. There you can have all oil passages restrict with age, but when cleaned the thinnest layers will be removed first. This mismatch in supply and outlet can temporarily give the appearance of an oil flow issue, yet the supply is greater than it was previously. It passes as the supply gallery gets further along.
In your case, as I recommend with all customer concerns of this nature, please change the filter. I'm unsure whether you have a cartridge or spin-on, but please examine it for grit/debris. This is the composition of carbonaceous ring deposits that all engines tend to form. It's a byproduct of the higher temperatures of the upper ring area and too much oil migration.
While this may not stop the offending noises, it will assure that filter saturation isn't an issue.
