Ticking noise

A ticking sound from under the hood could be several things including a cracked exhaust manifold or bad exhaust manifold gasket (both of which would be probably more noticable when the engine is first started up from cold. The most likely cause of the noise in your engine is that it is coming from the hydraulic valve lifters. Mitsubishi have a Service Bulletin regarding testing/cleaning the lifters. I would use the lowest viscocity engine oil Mitsubishi call for 5/30W and use an oil product called Risolene. It has low viscosity high detergency and may clean the lifters after one or two uses. I think its about 2 hours to replace the lifters plus cost of parts.

Check and replace the PCV valve..It makes a sound like crickets under the hood when they start to go bad..