Engine knock

Is it possible that we get a recording of the noise so that we can be sure to be on the same page?

Also, if you just replaced the oil pump then we need to check the oil pressure and make sure you have a functioning pump.

https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

If the pump is faulty then no oil pressure will cause the engine to knock so we should start with this.

If the oil pressure gauge in the dash (if equipped) says it is fine, then we should check it with a gauge just to confirm because if this happened right after replacing the pump then that is most likely the cause.

Please see the info attached on this and then let us know if you can get a video of the noise just to be sure we are talking about the same type of knock.

Thanks

Unfortunately, that is not good.

That is a lower end engine knock and the noise you are hearing is either the piston slapping the side of the cylinder wall, or a spun bearing and the piston rod is moving around as it spins.

Either way, if you continue to run the engine, there will be a rod thrown through the block and you will have a hole in the side of the engine.

At which point, you will have no option but to replace the engine.

However, at this point, you are going to have to completely disassemble the engine and rebuild it, but I suspect you are better off just getting a replacement engine now as they are not that expensive for this truck. The thing you have going for you is the parts are readily available and replacement engines are as well due to it being a Chevrolet.

Let me know if you have questions. Thanks

Okay. Great. Sorry, that is the case but that is great that you updated us because others may have this issue and can jump to this and check the bearings as well.

Thanks for using 2CarPros.