Additive question

[shell_user]

Hello again gents, and I know this sounds dumb, but does the level of additives in motor oil degrade or decrease as miles is put on the oil? Just curious and never thought of it so thought I would ask, and as they say the only dumb question is one you never ask.

thank you in advance for any help and advice on this question


adam

 

[Turk]

Additives deplete as the oil gets used more.

 

[skyship]

Most of the Moly, Calcium, Zinc and other additives remain in the oil, so you can tell from a UOA roughly what type of oil was used, BUT that does not mean the additives are working and to figure that part out you need a TBN figure to get some idea.
The figures for additives like Ca will rise slightly from the VOA to the UOA due to evapouration of the base stock concentrating the add pack to a minor extent.

 

[shell_user]

Yeah I was wondering if the additive count would drop or what. Thanks for the info folks and good info.

 

[Donald]

Certainly the ones that deal with the acids produced by combustion get depleted. You want to change the oil before that happens. This is what TBN is about.

 

[volk06]

Boron depletes with use. Youll see oil VOAs with over 200ppm and UOA with only 50ppm. I think sodium depletes as well but not as fast or much as boron.

 

[Gokhan]

Originally Posted By: volk06
Boron depletes with use. Youll see oil VOAs with over 200ppm and UOA with only 50ppm. I think sodium depletes as well but not as fast or much as boron.

Do you know why that is? Does the boron coat the metal parts? Or does it leave the oil in the form of a gas by evaporation? 3/4 of the boron was gone in my case. See the UOA and VOA here.

 

[mechtech2]

INTENTIONAL and good additives deplete.
UNWANTED additives increase!