Picked up a trick for rusty bolts from an old diesel mechanic in Nashville

I was down in Nashville last summer helping a buddy swap an engine in his '78 F-250. This older mechanic walked over, saw me fighting a rusted exhaust bolt, and told me to hit it with a torch just enough to warm it up, then spray it with water. The rapid cooling breaks the rust loose better than any penetrating oil I've used. Has anyone else tried this heat and quench method or do you stick with the soak and pray approach?

3 comments

3 Comments

the_alex15d ago

Gotta be careful with water on hot metal though, it can crack the manifold sometimes.

williamhenderson15d ago

Yeah, saw that happen to a buddy of mine. He poured cold water on a hot exhaust manifold and it cracked clean in half.

cole_murphy15d ago

Man, that's rough! Ngl, I totally get that. I remember I was cleaning out a boat motor one time with a cold hose after running it hard, and the block just pinged and split right down the side. @the_alex is spot on about being careful, water and hot metal is a classic way to wreck stuff fast. Honestly, sometimes you don't think about it when you're just trying to clean things up quick. Live and learn though, right?