Mechanical question: rod knock

Looking at a vehicle in my price range, and the owner says the check engine light is on. He claims he was told by a mechanic that it is due to “rod knock”.

Does anyone know how serious this is and how difficult it is to resolve?

Eventually (or rather soon, depending on how hard you push the engine), the rod will break and that will destroy your engine (see also “throwing a rod” - my parents’ snowblower did this and it punched a hole in the side of the block). Fixing it requires rebuilding the bottom end of the engine. So…it’s kinda serious.

It’s caused by running the engine on too little oil, so there may be other problems lurking as well.

However I’d be a little surprised if rod knock caused the light to come on. The light will come on if you have “regular” knock, AKA detonation or pre-ignition, which is where the air/fuel mixture combusts earlier than it’s supposed to in the piston’s cycle. It’s possible the owner got confused.

Either way, I’d keep shopping.

Thanks. It’s amazing what people think they can charge for a van that is more than 15 years old.

Oh yeah, forgot to mention, if it’s pre-ignition (knock, ping, etc.), eventually it’ll burn up the top of the piston(s). So, uh…yeah.

What Dak said. Run away from that van. Do not walk, do not trot, not even a jog. RUN.