I’ve learned that the radiator in my 2004 Mazda RX-8 was long overdue for replacement. Conventional wisdom says if a radiator is getting replaced due to age-related issues, it’s a good idea to replace hoses at the same time. Partly because they are flexible parts subject to wear from age, and partly because we have to remove one end anyway during radiator replacement. I added hoses to my radiator order.

First lesson: my locking pliers are my allies when battling hose clamps.

Second lesson: radiator hoses that have been clamped to the same fittings for over twenty years are reluctant to move. Once I freed the hose clamp, radiator-side hoses came loose with a hard tug. But the engine-side fittings were more challenging. It took far more effort to remove the top radiator hose and, once freed, I could see the problem: a layer of buildup acted as glue between hose and fitting. I think most of this is dried coolant, but some of it may be corrosion. Most of it crumbled when I scraped with my fingernail which I then wiped away.

The engine’s lower radiator hose is buried deeper. I chose to remove the secondary air injection pump to give myself more elbow room but I still couldn’t pull the hose free. Again I exercised my dial-an-expert option and Emily Velasco suggested working a screwdriver in there to free up the hose. This makes sense: I’m pulling parallel to the adhesion surface, the direction where it is strongest. I need to apply force perpendicular to the adhesion surface, like how we peel off a piece of adhesive tape.

However, tight quarters meant I couldn’t get a tool in there, but Emily had a simple solution: bend a screwdriver. I chose a small one that was bundled with my Creality Ender 2 and bent it into a tiny little pry bar. Now I could push the tip into the gap between old hose and engine fitting, and I could hear and feel the tactile sensation of those surfaces peeling apart.

Once the adhesive bond between hose and fitting was broken, I could pull these old hoses free clearing the way for radiator removal.