This. 3k mile OCIs didn't help my MIL's car either. It was changed religiously every 3k miles since she bought it new. After 11 years and 130k miles, it was burning a quart every 800-1000 miles. One run with HPL EC slowed the consumption in half. After the 2nd change with HPL PCMO 5W-30, it was down to just a quart every 5-6k miles.
The problem with oils that are volatile is the effects of that volatility happen the first time the oil gets hot. The first time the oil hits that 450°F cylinder wall, those light ends are going to burn and coke around the rings. You're not even a mile down the road after the oil change when this is happening so it doesn't matter how often you change it.
This engine had 200k miles at the time of this photo. It used HPL HDMO 5W-40 changed every 5k miles. Some would call that a waste, but show me a 200k mile engine this clean with 5k OCIs on Quaker State or Castrol. 3k OCIs even, it doesn't matter. Oils that run clean show benefits regardless of the OCI.
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