Would the depletion of ZDDP in a UOA indicate that metal to metal contact had been occurring--or at least could have occurred?
If I understand correctly, the zinc and phosphorous "sacrifice" theirselves to prevent metal from touching metal. Is that correct? When metal tries to hit metal these anti-wear elements step up, take the bullet, and get crushed into non-existence or something such?
But if the hydrodynamic film never breaks down, the zinc/phos/moly or whatever just kicks back and enjoys the ride; the EP add pack remains largely intact. Right or wrong?
So if you're looking at a UOA and you see some metal numbers which are higher than average... and you also see that the ZDDP count is down from what it was on a reliable VOA--is it reasonable to assume that those metal numbers were racked up during this OCI?
It has been advanced that high metal in a UOA may be from metal laiden old sludge which has been "washed clean" by the new oil. And that's certainly plausible.
But if the wear metals really are from old sludge, then the EP add pack should be mostly all present and accounted for.
Right?
Dan
If I understand correctly, the zinc and phosphorous "sacrifice" theirselves to prevent metal from touching metal. Is that correct? When metal tries to hit metal these anti-wear elements step up, take the bullet, and get crushed into non-existence or something such?
But if the hydrodynamic film never breaks down, the zinc/phos/moly or whatever just kicks back and enjoys the ride; the EP add pack remains largely intact. Right or wrong?
So if you're looking at a UOA and you see some metal numbers which are higher than average... and you also see that the ZDDP count is down from what it was on a reliable VOA--is it reasonable to assume that those metal numbers were racked up during this OCI?
It has been advanced that high metal in a UOA may be from metal laiden old sludge which has been "washed clean" by the new oil. And that's certainly plausible.
But if the wear metals really are from old sludge, then the EP add pack should be mostly all present and accounted for.
Right?
Dan