Scotty Kilmer says to change a timing belt at least every 10 years, but because a broken timing belt could grenade an engine, it’s always better to follow the maintenance intervals in your owner’s manual. In many cases, the interval is between 50,000 miles and 80,000 miles.
What happens if you don’t change the timing belt?
It depends on the vehicle. If the engine is an interference engine, it could suffer catastrophic damage if you don’t change the timing belt. If your vehicle’s engine is not an interference engine, chances are that a broken or stretched belt won’t damage the engine, though there is that remote possibility.
You should know what type of engine is in your vehicle, and whether it uses a belt, chain, or gears.
Chains and gears also need changing, but not as often, and those engines are usually not interference engines. Continue reading to learn more about replacing timing belts.
Knowing When to Change a Timing Belt
Because the timing belt is inside a timing cover at the front of the engine, you can’t see it to check for dry rot and cracks. The only way to know is to read your owner’s manual. When a manufacturer tells you to change the timing belt at 60,000 miles, it means it.
The manufacturer has already run tests on the belts to see how long it lasts before it either breaks or stretches past its useful life.
Once the belt breaks, the engine will not start. If the engine doesn’t start, you can check to see if the timing belt is broken by listening to the engine. In most cases, the engine will sound like a sewing machine as it turns over, because it doesn’t have compression.
In some vehicles, remove the oil filler cap and look in the valve cover as someone cranks the engine. If your model does not have baffles hiding the valvetrain, you should see it move. If it does not, the timing belt is most likely broken.
How to Change a Timing Belt
Some timing belts are easily accessible and don’t require special tools. Others are a bear to get to and do require special tools. However, the general process is the same.
Step 1: Remove the serpentine belt or fan belts if your vehicle uses fan belts.
Step 2: If the air intake is in the way, remove it.
Step 3: Remove the motor mount that is in front of the timing cover. For some vehicles, you might not have to remove it if you have enough space to reach the crank pulley.
Step 4: Remove the water pump pulley. Before you remove it, spin the pulley to make sure it rotates smoothly and does not make grinding or squeaking noises. If it does, it might be time to replace the water pump.
At the same time, look for signs of coolant leaks where the pump mounts to the engine and at the weep hole. If you cannot see the water pump, it is under the timing belt cover. You should replace the water pump whether it needs it or not.
If it leaks, you’ll have to do that work all over again, and if enough antifreeze gets onto the timing belt, it could damage it.
Step 5: Remove the timing belt cover. It might a one-piece or two-piece cover.
Step 6: Remove the crank pulley. In some cases, you might need a puller to get the crank pulley off.
Step 7: Using white-out or marking paint, make a mark on the top tooth of the camshaft sprocket and on the engine right above the camshaft sprocket.
If your engine has two camshaft pulleys, mark both pulleys at the top tooth and top of the engine, but on the second camshaft pulley, use the 3:00 position instead of the 12:00 position.
Make another mark on the bottom-most tooth of the crankshaft sprocket and on the engine.
Step 8: Without moving the camshaft sprocket or the crankshaft sprocket, remove the idler pulley for the timing belt. Slide the belt off the sprockets.
Step 9: Install the new belt, making sure that you don’t move the camshaft sprocket or the crankshaft sprocket.
Step 10: Make sure the marks are lined up. If not, remove the belt, line up the marks, and reinstall the belt.
Step 11: Reinstall the idler pulley, making sure the marks do not move. If the marks moved, remove the idler and the timing belt, line up the marks and reinstall the belt and idler pulley.
Step 12: Replace the timing cover or covers, the crankshaft pulley, and the water pump pulley.
Step 13: Before replacing the serpentine belt or fan belts, check them over for signs of dry rot and cracks. If the belt has any glazing on it, you should also replace it.
Step 14: Reinstall the motor mount if you had to remove it.
Step 15: Start the vehicle and test drive it to make sure everything is installed properly.
Visit Vehicle History
When you buy a used vehicle, read the reviews and customer comments about that model before you buy it. You can learn if a particular model has inherent issues and check the recalls on the vehicle.
Finally, ask the seller to provide you with a maintenance record, including proof of changing the timing belt if the engine has over 60,000 miles. If the timing belt wasn’t done, or if the seller can’t show proof of the work, then count on doing the timing belt immediately.
