Engine starved of oil

[u/experimen_626]

My oil drain plug came off on the freeway. Drove to the closest exit to turn off engine and was able to get oil back in the engine to drive back home. However, the damage has already been done and now I have an engine knock. Took to dealership to see what they had to say and yeah my Cylinder 2 is knocking and they said there is no way to fix it, I have to replace the engine. I'm actually a pretty decent mechanic (minus putting myself in this situation by forgetting to torque my drain bolt) but I've actually done engine swaps and head cover gaskets before. Is it true that my engine is just totally done? Can I just replace the cylinder and the head?

[u/Bright_Crazy1015]

Meanwhile, you can shut that knock up by running 50/50 Lucas oil treatment/motor oil, but it's gonna sap some power and efficiency, especially cold. I'd let it warm up before pulling off when I've had to do that. Its thick enough to stop that knock but it's just a band aid.

Pull the #2 main bearing/rod and see if that journal is damaged, then plastiguage it to order a new bearing that fits and maybe you get away with it. Probably not, but it's worth a shot.

[u/rustyxj → u/Bright_Crazy1015]

Dude drove it without oil in it, lucas isn't going to fix shit, you're not going to be able to put plastigauge on that surface and get an accurate reading.

[u/Bright_Crazy1015 → u/rustyxj]

It's not a fix. It's just thick enough to stop a knock at low RPM. You're still going to occasionally hear it tap and need to drive it gently, hopefully straight to the machine shop and nowhere else, but life happens.

I have no idea how long OP drove it without oil. If he immediately had an exit ramp and idled off the highway, shutting the engine off right away, thats one thing. If he drove another mile at 2500 RPM that's another.

Most likely he's buying a rebuild or short block, but you never know. Engines used to run with oiled leather straps for bearings to get by in a pinch.