Vent: Old school mechanic told me to stop using penetrating oil on rusty bolts

I had this guy, maybe 70 years old, at the parts counter in Portland last month swear up and down that penetrating oil is a waste and to just use heat on everything. I tried his method on a seized exhaust manifold bolt and snapped it clean off, took me 3 hours to drill and tap. Has anyone else gotten bad advice from an old timer that backfired on them?

2 comments

2 Comments

gray_roberts17h ago

Heat is king for some stuff but not everything man. I switched to a 50/50 mix of acetone and automatic transmission fluid in a little squeeze bottle a few years back and that stuff seriously works better than any store brand penetrant. Soak it, wait 20 minutes, then tap the bolt with a hammer before you wrench on it. The ATF creeps into the threads way better than WD-40 or PB Blaster in my experience. Sucks you snapped that manifold bolt, I would have been furious too after drilling and tapping for hours.

richard_sanchez4313h agoMost Upvoted

Kind of reminds me how people get stuck on one way of doing things and treat it like gospel, when really every job is different and you gotta adapt on the fly.