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Replace a timing belt

07-23-2009, 04:26 PM
I have a 99 Avalon with 150K and when I first start the engine I get a squeeling noise that sounds like the belt or pulley. I want to change the timing belt, but need some instructions and other item that should be changed or replaced at the same time. Can anyone help?



07-27-2009, 07:39 AM
The belt squealing is probably coming from your accessory belt being loose or worn. It has a smooth or ribbed surface that will slip on the pulleys if it has become stretched and loose. Turning on the A/C in particular can cause the squealing sometimes and may indicate some wear or a rising problem in the A/C's compressor since the increased load of turning it on can cause resistance and slippage.

The squealing is not related to the timing belt which is located beneath a plastic cover and has a toothed design to prevent slippage, which if it were to happen would cause the crankshaft and camshafts to go out of sync and thus would not be able to run well if at all. However, if you still have the original OEM belt I would definitely recommend changing it since Toyota recommends they be changed every 60k miles or so. Certainly find out when/if it was last changed.

If you do wish to change the timing belt, and since you're going to have the front of the engine disassembled anyways, I'd recommend changing all the oil shaft seals (cam, crank, oil pump), tensioners, idler pulleys. The water pump is easy to do, but it does require draining the cooling system first and is quite hardy. I'd hold off until the next belt change.

Hope this helps!

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