Did I toast the engine?

[Jake Raby]

Thats not a lifter... You more than likely injured a cylinder, or a piston.

That noise that sounds like a lifter fools people all the time, and they waste money. Its easy for an AOS failure to impact a cylinder, or a piston. The sound is EXACTLY like a lifter. The noise may also be a rod bearing thats been injured from having low oil pressure.

Driving with a bad AOS is murder in way too many instances.

The reason the OP light was on is because the extreme vacuum created in the crankcase by the AOS failure was pulling oil away from the oil pick up tube. Again, this is normal for AOS mode of failure #2, it just means that the membrane failed in the opposite manner that it does most of the time, and this is the most harmful.

With the OP light on you had less than 6 PSI of oil pressure. Thats not enough for more than 2,500 RPM of safe operation without damaging internals.

Don't judge a book by it's cover. Pull the oil sump and look for material, then pull the filter and cut it apart. If the issue is a cylinder it will often NEVER have debris in the oil.