Extend OCI'S progressively say 13k then 16k miles with used oil analysis after each. If it's still good stick with that. 16k is perfect since you could change oil every 2 months instead of what you're doing now every 5 weeks. 2 used oil analysis is what $60-70. Could save a busy guy like you some time and time is $$. You could also use a Fram Ultra or maybe even a Tough Guard.
.
People who are able to make this kind of prediction of future performance based on a PDS or spectrographic analysis are amazing. How do you do it? I sure can't.
Pity those poor blenders and formulators that can't either. They have to spend thousands on time-consuming and lengthy engine tests.
I have been seeing low Phos on a few VOA recently here.
Is the API 600ppm MIN (800ppm MAX) for certification out the window?
I threw a flag when noticed, I don't think I had any responses from guys here..
___________________________
On another note I had excellent results with QS FS 10W30 a couple years ago in the Ford. Even ran it in the Winter in the North East no cold start issues. This was when QS was advertising PAO-like pour points on the FS 10W30
I would use the 10w30 in a fleet vehicle and change after at least 12K min with that size sump - no fears.
The Quaker State Ultimate Protection is only about $1 more for the 5 quart jug, and it is marketed as a 20,000 mile oil, and is the top oil in the Quaker State lineup. Might be worth a consideration based on your use case.
People who are able to make this kind of prediction of future performance based on a PDS or spectrographic analysis are amazing. How do you do it? I sure can't.
Pity those poor blenders and formulators that can't either. They have to spend thousands on time-consuming and lengthy engine tests.
On the other hand I personally don't believe much of anything on a Blackstone analysis. They have been shown to be unreliable on both spectrographic and viscometric results.
Without anything else to go by I'll stick with the API license it has.