I work in a busy Indy shop and we run stp fluids in everything. We see the same vehicles all the time for various services and repairs. Never had an issue
Stp oils and transmission fluids from AutoZone are blended by Amalie. No issues with any of these products. In fact I have stp multi vehicle transmission fluid in my wife's Hyundai Santa Fe on a full transmission service. Been in her transmissionmission for about 2 years now. Shifts...
Hard to predict. I've seen engines in horrible condition continuing to run. They may consume oil or have lots of blow-by or smoky exhaust but still running. Those 4.3 engines were awesome. I have a 1994 4.3. they did tend to shed lots of iron that had you not had the magnet drain plug you...