will the engine make a noise
What signs will tell you that the timing belt needs changing?
Nothing! You have to pull the cover back and look at it. There is no sensor that tells you it's bad. Never run a timing belt over 100,000 miles. Honda recommends changing theres every 60,000 miles. Not sure about Toyota but I'm sure it's about the same.
What signs will tell you that the timing belt needs changing?
usually you wont notice until it snaps. try to replace it as a precaution by about 125,000 to 150,000 miles or sooner if you have a lead foot.
nothing
You just change them at regular intervals
where is the noise coming from?
If your Toyota is after 1996, there is a sensor that alerts you if the timing is bad, but this is too late in my opinion. Go by the mileage, a belt should do 100,000 or even more.
When you do the belt, also change the water pump and the oil pump gasket.
Unfortunately there's no way to tell if your timing belt needs changing without removing the upper plastic cover to inspect it visually. If your in doubt as to if it needs to be changed I'd strongly recommend changing it ASAP, if not for piece of mind, then for the saving of hundreds of dollars by doing so. Since you didn't give what year, make, and engine size it's hard to say what will happen if it were to break.The majority of engines are interference motors which tend to bend valves when the t-belt breaks. The saying %26quot;Pay a little now or PAY allot later%26quot; definitely applies when it comes to Timing Belts. Good luck and hope this helps.
