I tried to tell them the same 15 year old common knowledge in laymans terms and was jumped on by the peanut gallery. They told me if I kept posting nonsense that I would not last long. Thank you for posting what they should already know.
I mean, 1995 (the date of that study) isn't 15 years ago, it's 30. But anyway, what you said was:
Stumalump said:
The trick is this: Oil is full of addatives that do not last as long as the oil. The good news is that you can tell exactly when additives fail. The level drops fast over about 500 miles. Might be a 1/4 quart or a half. That is when the additives break down and turn to vapor.
And:
Stumpalump said:
When you see the small drop it’s a great indication that the oil in that particular application needs to be changed and that is usually about the same time the ZDDP, molly or other addative you may be specifically concerned about is gone as well. Find the drop zone or milage and that is when you change it. Ones I know and remember are mitsubishy V6 only lasting 3000 miles, newer dodge V6 last 4500-5500 Miles. V10 in Ford truck is at 4000 when you see the drop in level. New company car Pacifica runs 8 or 9000 before it drops. The fleet manager lets me change it at 10,000. Best is change it at that drop level or if you want to hack the life longer because you are on the run then it’s the only OK time to add STP, lucus oil stabilizer or other snake oil additive because they are loaded with the additives that burned off.
I actually agreed with you that phosphorous will deplete over time, as I'm sure you recall. Where you ran into some issues were the claims that:
- The additives turn to vapor
- A drop in oil level signalled that this had happened
- A drop in oil level indicates the oil needs to be changed
- Lucas or STP replenishes additives because they are "loaded with them"
There are many different types of ZDDP, which
@RDY4WAR I'm sure can expand on. There are several types of moly, as well as other FM compounds. Phosphorous retention (81% minimum), as noted, is covered in Sequence IIIHB, the details for which can be found here:
https://cdn.standards.iteh.ai/samples/106209/d8d3c805ead7450087a0c639db5a4268/ASTM-D8111-20.pdf
This is a 90hr test performed at high RPM and high load on a 3.6L Chrysler Pentastar engine. What 90hrs translates into in miles/km in your application will of course depend on the average speed of the vehicle. On my wife's truck, that's about 31km/h (lots of in-town driving) which in turn means ~2,800km.
Assuming (and the charts in the post you are quoting support this) a rather linear rate of decline, even if you had an oil that was crap and was right on the 81% threshold, that's 0.21% per hr, so to get to say 50% depletion, we are looking at ~240hrs, which, in the same application is ~7,400km.
Engines can consume oil for a wide variety of reasons. My old 5.4L drank 3L of AMSOIL SS 0W-30 between changes, but zero Mobil 1 AFE 0W-30
Do I think that's because the engine consumed 3L worth of additives with the AMSOIL? No, of course not.
Oils, and OE approvals, developed for extended drains, are going to have better phosphorous retention, AW and FM performance.
And then of course there's the fact that oil doesn't age in miles. This is why industrial applications use hours. This is why IOLM's use engine hours, load, temperature and many other parameters to determine OCI length. Mileage counters are dumb, because they don't in any way account for factors like the rate at which the vehicle was driven and the conditions under which it was operated.
