B6304 and B6254 timing belt change
Timing belt change (Volvo B6254 & B6304)
Volvo's six-cylinder tin engine is designed for serviceability: to replace the timing belt, you do not need to remove the crankshaft pulley or the auxiliary equipment belt tensioners.
Do I need to remove the radiator fan?
The fan does not have to be removed, but it is held in place by only two Phillips head screws. Removing and moving it to the side provides considerably more working space, which makes it easier to monitor the marks. The electrical connector does not necessarily need to be disconnected if you carefully swing the fan to the side.
Where can I find the timing marks?
The marks are small in this engine, so they should be carefully cleaned into view: Camshafts: There are alignment notches in the backing plastic behind the shroud. The left (intake) notch is approximately at 2 o'clock. The right (exhaust) notch is approximately at 10 o'clock. Note: The mating marks are small stamped dots on the outer edge of the gears. Do not confuse them with possible marker pen marks from a previous technician. Crankshaft: The alignment mark is on the block (oil pump cover) at 12 o'clock. The mating mark is a small groove on the back edge of the crankshaft gear tooth.
What should I be aware of when removing the belt?
When the belt is removed, one of the camshafts will not stay in place due to spring pressure on the valve springs, but will rotate slightly to the side. This is normal, and the shaft must be rotated back to its mark when installing the new belt. Rotate the engine to top dead center (TDC) before removing the belt.
How does the belt tensioner work?
Below the shroud is an automatic hydraulic tensioner, a guide roller, and a water pump. The tensioner unit is held in place by two bolts. When installing a new belt, the tensioner piston must be slowly compressed (e.g., in a vise) and locked with a pin before installation. The pin is removed only after the new belt is in place and the marks are verified.
What else is worth replacing at the same time?
At the same time, it is recommended to replace: Tensioner roller and guide roller: A bearing failure in these can snap even a new belt. Water pump: Check clearances and for leaks; the pump is easy to replace while the belt is already off.
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