Quote:
Originally Posted by olddog
I must point out that depending on what you are looking for in the oil, the way you take the sample could add a lot a variability. Leave oil set and the heavy stuff sinks and the light stuff goes to the top. It is very possible that the lab correctly measured two samples from the same oil with different levels of what ever, due to segrigation. |
Oil sample taken in the identical fashion -- after a drive, via suction through the dipstick hole, tube placed the same distance down so that the sample came from the middle of the oil pan (not the top of the pan, not the bottom of the pan).
My
Zinc and Phos. numbers varied widely; so widely that I wondered whether the ZDDP would "pool in clumps" and thus miss the sample pickup but nonetheless bond to the iron and steel as it went through the system. I don't know. I gave up on playing that game and instead use Brad Penn with a bottle and a half of EOS. BTW, the virgin sample of the BP that I sent in came back with low
Zinc and Phos. numbers as well, but some other forums had users that had the identical experience with that particular lab. IOW, that lab tended to low-ball the ZDDP numbers.