Exhaust manifold leak (issue)

[phlegm]

I hear a strange noise from the engine that a few of my shade trees and I at church have decided is a leak at the exhaust manifold. Before I tear it down I want to make sure there is not something easy that could be causing this that can be fixed without removing them.

From what I understand there is a thermostat type device that constricts the flow out of the exhaust in order to warm the engine up faster, and these devices are on both sides and can leak from the seals after a while.

Is this true? and should I check this first. any other obvious things to check? Just want to get as much Background as I can before I start digging in. Thanks in advance.