August 17, 2018

Is a special oil filter required when using Royal Purple?

While no special oil filter is required, we do recommend upgrading to a high quality oil filter. A high quality filter will prevent contaminants from circulating […]
August 17, 2018

Can your oil be used with flat tappet cams?

Yes. For stock, non-performance valve trains, Royal Purple API-licensed oils (API SN and ILSAC GF-5 licensed) are OK. For upgraded performance flat tappet camshafts, and vintage […]
August 17, 2018

Do your motor oils contain zinc/phosphorus?

Yes. All Royal Purple® engine oils contain the zinc/phosphorus compound zinc dialkyl dithiophosphate (ZDDP), but the maximum amounts are restricted by the current API oil specifications. […]
August 17, 2018

Does Royal Purple maintain its purple color after it’s put into service?

No. The dye that’s used to color the oil dissipates shortly after being put into service. The oil will appear brown at some point.