Like timing belts, timing chains drive a vehicle's camshaft. Stronger than their counterparts, timing chains are nearly repair-free with no definitive replacement schedule. If your Toyota Corolla produces a vociferous rattle whenever you accelerate, chances are it's time to check and replace your timing chain. Consider changing your water pump at the same time since you have to disconnect it anyway.
Check your owner's manual for the recommended mileage for replacing your timing chain. Replacement recommendation for a Toyota Corolla is 60,000 miles.
Locate the timing chain.
Replace it there is damage to the automatic chain adjuster (also known as the tensioner.)
Deplete the cooling system.
Disengage the negative battery cable, right engine cover and mount, accessory drive belt, generator and tensioner, power steering pump (sans the hoses) and the cylinder head cover.
Remove the crankshaft pulley, angle sensor plate and the position sensor from the timing chain cover. Take out the cover, tensioner slipper, vibration damper and the timing and crankshaft timing sprockets.
Undo the chain tensioner, water pump and the valve timing control assembly and camshaft timing sprocket.
Force the seal from its cover. Extend the timing chain to its maximum length and measure the span of any 16 successive links, not to surpass 4.827 inches (122.6mm).
Examine the slipper and damper for wear. It should not be more than 0.039 inch (1mm).
Secure the tensioner plunger in place.
Put engine oil on from the top of the intake camshaft until it returns to 16mm. Line up the valve timing controller and the knock pin timing marks and insert the controller into the camshaft. Place the No. 1 piston to "Top Dead Center" (TDC). Position the crankshaft key at 12 o'clock.
Secure the sprocket bolt to 33 foot pounds (45 Nm). The camshafts should line up with the sprockets' point marks. Tauten the chain damper bolt to 96 inch pounds (11 Nm).
Align the timing chain with the crankshaft and camshaft sprockets with the yellow links. Attach the following: chain tension slipper, crankshaft angle sensor plate (F mark is forward), new front cover seal, silicone sealing for the timing chain cover and the cover.
Reinstall the water pump. Secure the 10mm "C" bolts to 80-inch lbs. (9 Nm); "A" bolts to 10 ft. lbs. (13 Nm) and the other 10mm bolts to 96-inch lbs. (11 Nm). The 12mm bolts should be at 14 ft. lbs. (18.5 Nm). Tighten the stud bolt to 82-inch lbs. (9.3 Nm).
Reconnect the right engine mount bracket, drive belt tensioner, crankshaft position sensor and pulley.
Constrict the chain tensioner and put in a new tensioner with new O-rngs. Tighten the bolts to 80-inch lbs. Put the hook on the pin to maintain compression. Rotate the crankshaft to the left and take the hook out. Rotate the crankshaft to the right until the tensioner slipper moves past the plunger.
Line up the timing marks on the crankshaft pulley and the timing chain cover. The camshaft sprockets' timing marks should be facing each other.
Reconnect any remaining items and replace the coolant. Start the engine and check for leaks.
Make sure the new timing chain matches the one being removed. Procedures for replacing timing chains in a Toyota Corolla vary depending on engine size.
Never reuse O-rings.