Making a loud rattling sound under the hood

As soon as u crank up the vehicle it sounds like there is a bolt loose in the actual engine bouncing around. And I have examed it but there none that I can see

No the fly wheel cover is ok an the highr the rpm the louder the sound. Idling if you stick ur head under the hood it sounds like it's from the top get under the truck an it sounds like it is coming from the bottom. The exhaust shield is secure.

It is comin from the right side of the engine An its internal sounds like somethin in the cylinders. And it's a tapping or knockin but more tapping. It go's along with the motor so any ideas?

No they are find

There are several things that can cause the rattling sound in your engine. First thing would be to check that your water and antifreeze level is good, and flowing properly. Take the cap off the radiator and start the engine. If the water starts spewing out of the radiator you either have a thermostat that is sticking or the water pump is not working properly.

Second, check your oil to see if it is low. If it isn't, you may need to do what I call "double change your oil." On the first change let it run for a little while. Let the engine cool off, and filter the new oil as you drain it into a clean oil bucket or pan. Pour this oil back into the engine, run it again for a few minutes. If this doesn't queit the clatter then you either have oil pump issues and/or an issue with your crankshaft.

A good automotive place can diagnose the issue rather quickly with their equipment.