Toyota Serpentine Belt Replacement

by Matt Scheer
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The Toyota engine uses a serpentine belt to rotate many of the accessories of the engine, such as the air conditioning compressor, the alternator, the power steering pump and the water pump. Replacing the belt is a routine maintenance job and shouldn't take more than 30 minutes. The brevity of the job shouldn't mask the importance of it, though, because when a worn serpentine belt breaks in an active vehicle it can tear through pulleys, forcing you to replace all of them.

Check the Belt for Wear

According to Popular Mechanics, a new serpentine belt can last 150,000 miles. But if you bought your Toyota new, you'll need to change your serpentine belt after about 30,000 to 60,000 miles. The process isn't difficult and doesn't take any special tools. Plus, the belt itself won't cost you an arm and a leg: any auto shop should carry these belts for around $30 to $50, as of 2010. Because the belt itself is so cheap in comparison to the damage a worn belt can do to the pulley system, it's worth checking on the belt to see if it needs to be replaced.

When you check on the serpentine belt, turn off the Toyota and let the engine cool. You don't want to risk burning your hand by working near an engine when it's still hot. You won't need any supplies except a flashlight to check the quality of the serpentine belt, but if you do decide to replace it, you'll need a drive socket wrench and a belt tension gauge, which measures the tension on the belt to ensure it's tight enough.

Prop up the hood of the car and inspect the serpentine belt, looking for any cracks, tears, frayed strands of rubber, or oil. If you see oil contamination, that means there's an oil leak somewhere in the engine and you'll have to take the car in for a mechanic to find the leak, which may require him to put the car on a lift. Twist the serpentine belt over to look at the groove ends. The grooves shouldn't have any missing chunks of rubber or breaks in them. If the belt looks worn, visit an auto shop to buy a replacement belt, which the assistant can find for you when you tell him the make and model year of your Toyota.

Replace the Belt

With the replacement belt nearby, open and prop up the hood again and look for the serpentine belt routing sticker. This is a diagram that shows how the belt is routed around the pulleys. If you can't find this sticker, perhaps because it was painted over by a previous owner, get pencil and paper and draw how the serpentine belt looks on the pulleys. This is an essential task, because if you put your replacement belt on the pulleys incorrectly, turning the engine on can tear through the new belt.

Use a drive socket wrench to release the tensioner pulley, which holds the old serpentine belt tight against the other pulleys. This is the hardest part of the process. You may need to use a lot of force to free the bolt that holds the tensioner pulley in place. Once it's released though, the serpentine belt will easily slip off the other belts.

Before you put on the new belt, compare the old one to the new to ensure that you've bought the right belt. If you don't, your new belt may be too big or too small. The number of grooves, width, and length of the belts should all match. If you've got a match, put the new belt around the pulleys, starting at the tensioner pulley. Wind the belt around the other pulleys exactly as it's shown in the routing sticker or the diagram you drew. Replace the tension on the belt by using your drive socket wrench to push the tensioner pulley back into place. Now, before you start the engine, use the tension gauge to make sure the belt has the correct tension on it. Once this is done, start the engine with the hood open so you can see that the belt rotates around the pulleys smoothly. Check this once more after about 200 miles of driving.

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