2003 Dodge Intrepid

You don't necessarily need a new engine. But you should definitely find out what the noise is.

It could be a small part that has come loose and is flying around in the engine. After removing/replacing it, you may just be able to get another 50K miles out of your motor, who knows?

But with 170K + miles, it's also a possibility you'll need a new motor.

Don't just cough up the cash on a new motor though, without finding out the source of your noise.