Loud engine noise or knocking when AC on

Check your AC compressor & clutch open the hood,running with AC on

You didnt state vehicle however if the engine knocks the knock sensor will back off the timing thinking its detination not an actual knock if its knocking loudly stop driving it, something is going to let loose

I would expect the engine is damaged.
You'll need to check the oil pressure and try to narrow down the area where the sound is coming from to proceed.
A very loud knock is probably a piston or rod bearing.

Sounds like car has been overheated and has a collapsed piston skirt. This will cause piston slap until piston heat up and expand.-------------------------------------------------------------------------
vas 5054a

Theres a neoprene chain keeper inside front engine cover if that was broke loose in there it might have wore your belt to the point that it broke

If it is coming from the engine compartment it may be the clutch on the compressor.

Blue Steam ? Could be Bad Ring's but if it knock's might be a Rod knocking on the Crank !

This may also be a warped flywheel.

When the timing chain goes if the valves are fully open they won't clear the pistons (likely the loud thump you heard) when they come to TDC. Likely looking at a full blown valve job now, make sure it didn't crack or warp the heads in the process. With 192,000 miles on it it was probably due for one anyway. Easiest way is to pull the heads off the block and send them in for a machining and valve train replacement (about 4-$600.00 if you DIY.

My rio kia bought on from uyi technical dealer in benin city, edo state of nigeria only 4 months ago is vibrating with noise while driving. The noise is noticed by other road users even in motion, making a very loud noise or sound that is highly embarrassing. The dealer mechanics have checked more than twice yet no result, instead the hub bearing is observed; tyres are turn over yet the noise persists.

What do think is resolution to the problem? pls help me. Vinson- [email protected]