Mitsubishi Repair: Timing belt, reverse gear, air fuel mixture, internal engine components

Question
Hello Anthony,
I've a 2001 Mitsubishi Galant with a mileage of about 67,000.
Can you tell me when i need to change the timing belt.
What is importance of timing belt in the car? As per the manual, I may not change the belt if i live in states like California. Couldn't understand what this means.
And also, i get a beating sound when i'm in the reverse gair. I dont have this problem when I'm in drive/Park. Is there a problem with my transmission?

Thanks in Advance,
vatsa


Answer
Vatsa,
For most Mitsubishi engines, it's recommend that you change the timing belt and associated components every 60,000 miles.  Your owners manual should give a maintenance schedule for your specific car.

The timing belt is one of the single most important components for your engine to be sure it's running properly.  For your engine to run, the cylinders and valves must be in the exact correct position when the measured air and fuel enters the combustion chambers. When all of that is correct, your spark plugs will create a spark to ignite the air/fuel mixture to properly push down the cylinders and open and close the proper valves.  All of this must happen in perfect synchronicity.  If any of these items is off, the engine will not run properly, and could possibly break internal engine components.  All of this works the way it should because of the timing belt.  For a state like California, they have the most stringent emissions rules. Beacuse the timing belt controls the performance of the engine, if the timing is altered, it may alter the exhaust emissions.  But if you lived in California, and the belt were break or really needed to be replaced, the dealership would have to replace it.

As for the transmission problem, it would be best to have a transmission shop or the dealership inspect any strange noises or occurances.  
Good luck!