I have a 2003 Town and Country,A noise like a can rattle is coming from the lower part ofthe engine.When it is park the noise is low. When the van is in drive the noise gets louder. The noise is coming for the bottom of the engine.
I think the best thing you can do with this is to take it to a shop and let them listen to things then see what they think the trouble is. The trouble may be between the engine and the transmission system.
A common source of a rattle like this is just a loose heat shield on the exhaust system. Someone will just need to put it up in the air and inspect the exhaust. If that is what it is then this is no big deal to take care of.
The heat shield suggested by Cig is a common cause of rattling. If it is that, a simple large worm-style hose clamp from the hardware store can secur eit and is the traditional fix.
But, as Cougar and Cig suggested, the only way to find the cause is to put the car on a lift…or on jack stands…and get under it.