Get one of those mirrors that is attached to a telescoping rod and a strong flashlight. Look for signs of black soot where the manifold meets the exhaust ports on the engine and for soot on the surface of the manifold itself indicating a crack. of course soot where the manifold hooks up to the exhaust. You can remove the main bolts that hold the motor mounts together and jack the engine up with with a bottle jack or small floor jack to gain some room to work. Make sure to place a piece of wood between the jack and the oil pan to spread out the load so that you don't do any damage by collapsing it. You may have to loosen the transmission mount also so that you don't damage it when lifting the engine. I hope this helps and good luck,----Chuck | 
exhaust manifold 
