How does zinc (ZDDP) act as an antioxidant in oil?

Zinc dialkyldithiophosphate, commonly referred to as ZDDP or just Zinc (or sometimes ZDP, ZDTP, ZDnP) is the world's most popular lubricant additive. In a separate video we looked at its antiwear capability, but the power of ZDDP is that it is a multifunctional additive. In this video we look at how it helps to break the auto-oxidation cycle by disrupting the Hydroperoxide decomposition process.
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[@saravananmj729]

Saravanan

[@flinch622]

Sounds like the advance of [nat gas] synthetics might need some sulphur added back in?

[@lubonaluyando8288]

Could you do a video on Zinc Free Lubricants like Railroad Engine Oils too?

[@LubricationExplained]

Good idea! Let me look at it. It may not warrant a full video because from memory it’s simply that railroad engines contained silver in the bearings and ZDDP isn’t compatible with Silver, so alternate anti wear additives need to be used. Let me do some more research though.

[@shahnewajenayetkarim7992]

Is the Zn from ZDDP in Engine Oil & Hydraulic Oils are of same chemical in nature /compatibility?

[@LubricationExplained]

Great question! There are two broad categories of ZDDPs - you may have heard of primary and secondary ZDDPs. This refers to the manufacturing process and whether a primary or secondary alcohol was used. Historically, engine oils have been formulated with primary ZDDPs and hydraulic oils with secondary - the antiwear film deposition appears to be activated by temperature and primary ZDDPs activate at a higher temperature than secondary. These days engine oils are more likely to be a mix of the two. Needless to say, the two additives are compatible with each other because they are chemically almost identical. Hope that helps!

[@shahnewajenayetkarim7992]

@@LubricationExplained Thanks for the well explanation. So can we blend Engine Oil in a Kettle without flushing where last product was Zn based AW series Hydraulic Oil? As per my choice & safety I always follow flushing.

[@ejazahmednaqeeb]

@@shahnewajenayetkarim7992 Looks like we can do that!!!

[@LubricationExplained]

@@shahnewajenayetkarim7992 Wouldn't want to comment on manufacturing because we don't have expertise in that field and not sure whether you'd end up with performance variability. But you shouldn't run into any incompatibility issues at least.

[@drnavinkiranmurty8458]

Please touch on phenolic antioxidants also

[@LubricationExplained]

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[@KaLeB_]

Can you explain why diesel engine oils work so well in motorcicles? No one other oil, even the ones specific for motorcicles doens't stand and work so well like the diesel's oil....

[@bobspittle3201]

In our race cars we always ran diesel oil. Worked much better than traditional oils.

[@colinkensley]

Please add motorcycle oil to your channel