Overheated engine. Now, it knocking.

I was driving my Mustang around when it overheated. Instead of pulling over and waiting for it to cool off, I tried to limp it home. Now, it knocks....

I've never actually had an engine that knocked and really never put much thought into what causes an engine to knock. I know that it's normally called a, "Rod Knock", but I'm not sure if the rods are what's actually knocking. I'd like to pull the engine and try to fix it in an economical fashion. I plan to build an upgraded engine down the road, but am not ready to take that step right now. Before pulling the engine, though, I hope to have a reasonable plan of attack for fixing it. The engine still runs fine...just knocks.

So, when an engine is overheated and starts knocking, where could the knock be originating from: rod bearings, piston pins, pistons, main bearings?? I hope it's as simple as pulling the engine, getting it on the engine stand upside down, and swapping out some bearings.

Have a good day!
Michael

piston.

richter69 wrote:piston.

This is more of a curiosity line of questions than an, "I need to know exactly what's wrong with my car" line of questions.

So, if it is a piston. What actually happened to the piston to cause the audible noise now? If it's a rod knock, what would have actually happened to the rods or rod bearings to cause the audible knock? Basically, when an engine overheats, what's actually happening to the dimensions of the parts? If it were a rod knock, would a set of bearings normally fix it? Or do the rods commonly go oval? Do the pistons expand so much that it scuffs the cylinders?

Thanks for entertaining my questions .

Have a good day!
Michael

When a engine overheats to wear it start knock you have cooked the oil. Just like cooking grease thick until you put it in a pan/pot and heat it to cook with it get real thin.That is the same thing engine oil does when you run a engine hot until it starts steaming/steaming water mean you have got it past boiling point and the oil is as thin as water and not protecting bearings causing them to knock and beat the crank,rods,and mains.I would say it not going to be a easy fix if it knocking from rod or main bearing you need to pull the crank and have it turned down to clean it up and if it a rod have them checked.Your bearings will more than likely be blackish.The wirst pins not getting oil can make it knock by the pin trying to lock down on the pin.