John, >And my question is, if you and I are having airlocking problems with these >strainers, how come all the others are not? I wish I could be more help, but we haven't run with the Vetus strainers - this is a "theoretical" concern. The Vetus units we looked at had in/out fittings in the bottom of the case. This creates a potential airlock because of the high spot at top of case. Venting would require loosening the strainer top. Sure hope you find the source of your problem soon! Cheers, Steve ------------------------------------------------ Stephen C. Darden Email: darden@xtra.co.nz Adagio Marine Ltd. Fax: 649/4037-213 P.O. Box 161 Voice: 649/4037-801 Russell NEW ZEALAND