Jim’s Technical Tip
by Jim Cannon
For many years I had a hard time getting new radiator hoses on the engine to seal well. I would tighten the hose clamps to what I thought was reasonable, and they still seeped a bit of coolant. And years later, when I needed to remove the hoses, they seemed to be glued to the metal parts and I had to pry them off or cut them off.
A Master Mechanic shared his secret with me years ago. Apply a very thin coating of a specialized gasket dressing called “Hylomar AF” to the inside of the new hoses where they will contact the metal just before installing them. Install and rotate each hose back and forth, to spread the sealant out evenly. Now tighten hose clamps and you are done. It will not seep or leak. And years later when you need to remove the hose, it will come right off!
I get the Hylomar AF (Advanced Formulation) -- originally developed by Rolls Royce for their jet engines -- from an industrial supply place near me called W.W. Grainger. It’s also available on Amazon and other places on the Internet. Compare prices because some places price it like it’s gold!
There are several variants of Hylomar. You don’t want the original “Hylomar Universal Blue” or the “Racing Formula”. The Hylomar AF works best for our application. I also put a little on my oil drain plug threads, on the transmission and differential drain plugs, etc., to stop the drips. It gives a good seal but never hardens, so it’s easy to take it apart later.
Have a Model A Day! Jim
