Mazda Bongo Cam Belt Tensioner Bearing.
2.5 Turbo Diesel – (WL-T) – Chassis (SGL3, SGL3F, SGL5, SGL5F, SGLW).
Tensioner bearings are sealed permanently, so there is no way to clean or inspect the tensioner bearings once they have been installed. Most mechanics will replace the timing tensioner when replacing the timing belt.
If a tensioner bearing is failing and begins leaking grease, it will deteriorate rapidly.
Purpose of the belt tensioner
The timing belt tensioner is used to do just that – keep tension on the timing belt. The timing belt is a rubber belt that runs over and through a series of pulleys and gears. Over time, due to age and heat, the belt will stretch out.
The timing belt tensioner is part of the internal combustion engine of a vehicle, and it is responsible for keeping the timing belt moving at a consistent pace. The gear and chain systems that connect the timing belt to the crankshaft or camshaft will not work properly if the tensioner is worn, cracked or torn. Since the timing belt and tensioner are difficult to inspect without removing them completely, you will need to listen for specific noises to determine if there is a problem with the timing belt tensioner.
Listen for a rattling noise. A rattling noise when you start or accelerate could be an indication that there is too much pressure on the tensioner pulley, or that it is cracked.
Listen for rapid changes in rpm when you accelerate at low speeds. If the tensioner is not working properly, it may be very difficult for the car to pick up speed smoothly.
Check for oil leaks. If you notice signs of oil leaks within the engine around the camshaft or crankshaft, the tensioner could be cracked and is leaking grease into the engine.
Listen for an inconsistent humming noise. Intermittent humming may be a sign that the tensioner bearings are worn or torn.
Listen for squeaking or screeching when changing gears. A tensioner that is under too much pressure will begin to screech or squeal when shifting gears; this could be an indication that the tensioner is worn out and needs to be replaced.