It depends on the type of circulator and bearing used in the circulator bracket assembly. All sleeve bearing circulators require oil lubrication. Sleeve bearing bracket assemblies have a flip up oil fill cap on them. Check the operating instructions for your specific pump model to be sure. Don't forget to check the motor as well. Sleeve bearing motors have similar oil cups located on top of them as well. (Place instructions or link to the location on the website of operation and maintenance manuals here).