Look over the entire engine for any loose parts. Listen to see where the noise is coming from. The noise could be anything from a loose bolt to an engine going bad.
Could be your alternator problem.
Often when a vehicle air conditioner gets loud, the problem is due to a belt. You should take the car in to have the belt checked.
First check oil level. "Loud clattering" can be lifter noise you are hearing. This can indicate oil is not reaching the top of the engine or worn valve train parts. Another reason for noisy lifters could be the oil pickup is not picking up, could be clogged.
your engine is loud because, the fan makes that noise
If the 1999 Suburban noise is a sort of loud banging noise, the problem could be that the engine have jumped time. Jumping time would cause the noise and jerking in the engine.
Warped brake discs? Drive shaft? Rear axle?
Could be a bad CV joint. Have a mechanic check it out before you loose your steering.
Most likely they are engine mounts. As for the loud engine, check the exhaust.
If its a legitimate knocking then you would want to go with head gasket if its a tapping you would be looking at a valve
It is very loud like you can hear the engine from a distance.
Motorcycles are loud due to an Open engine. Loud and motorcycles go together.
My guess would be that motor is locked.