Next time your mechanic tells you that your car’s timing belt needs a replacement and may cost a thousand dollars or more, do not panic. Do not assume that the guy is trying to rip you off.
The timing belt is one of the most crucial parts of your car’s engine. If it fails, so will your engine, leaving your car in the shutdown mode for good. So it is essential to replace it periodically.
You are better off replacing it then and there instead of having it broken on the highway when you are driving at 80 miles per hour. It’s a definite safety issue.
What does the timing belt do?
The timing belt is an integral part of most combustion engines and synchronizes the rotation of the camshaft and the crankshaft. It causes the valves in the engine open and close at the right times so that the air and fuel flow through the engine.
The valves are opened when the piston sucks the air and fuel inside the chamber. This is called the suction/intake stroke.
The valves are then closed and piston gets the chance to compress the fuel and air (also known as charge). This is the compression stroke.
For gasoline cars, a spark plug ignites the compressed charge creating the explosion and giving the piston its power to push down. The valves are still closed. This is known as the power stroke.
After the power stroke is completed, the valves are opened. The piston again comes up exhausting the burnt charge out of the combustion chamber. This is the exhaust stroke.
The timing belt ensures that the opening and closing of the valves in the combustion chamber take place at the right time and in sync with the camshaft, and the crankshaft; basically the strokes of the engine.
When to replace the timing belt?
Unfortunately, there aren’t clear signs given by the timing belt before its demise. It will just snap off. That’s why most automobile companies suggest that the timing belt should be changed every 60,000 to 90,000 miles. Your car’s manual will provide the exact number for your model.
What is included in my timing belt service?
The process of servicing/replacing the timing belt is very tedious and requires the mechanic to first disconnect the battery ground cable. Once the engine cools down, the crankshaft is set to the top dead center with the first piston being on the compression stroke. Then the crankshaft pulley is carefully removed. All accessories that come in the way of the mechanic and the timing belt are removed. Camshafts are locked and the position of camshaft timings are marked. After removing the idler pulleys and belt tensioner, the timing belt is carefully removed.
Installing a new timing belt is basically the same process in reverse. The mechanic ensures that after the installation, the camshaft and the crankshaft are in perfect alignment. Then the engine crankshaft is turned two full rotations by hand, and the timings marks on camshaft and crankshaft are confirmed.
Your final bill may seem slightly heavier if a broken timing belt has damaged other parts of the engine such as valves, piston, or water pump.