On blocks and heads that have “suspect areas”, I have a “quick check” before I commit to bolting on the pressure test plates. I simply use my blow gun with a brake line attached, and blow air behind the questionable area, with some soap or bubble spray on the face side. This is a good way to figure out if there is an obvious crack that you may not be able to access with a magnaflux. Cam tunnel areas on blocks can crack and be easily identified VS bolting up the plates. It works good to quickly check valleys where you’re not sure if a rust witness is a crack or previous gasket leak. It’s not a substitute for mag and pressure test, but it’s a time saver to weed out the obvious areas in question. The tube can be manipulated to nearly any spot.
Ron Flood
Cedar Machine
North Branch, MN
