Volvo's rear-drive four-cylinder engines are renowned for serviceability. Timing belt replacement can be done with basic tools, but precision with the marks is essential.

B230-series (toothed belt): The recommendation is 80,000 km or 4 years. In older B19/B21/B23 models, belt condition should be monitored regularly, although they are often so-called "free-running" engines (belt breakage generally does not damage valves, with exceptions being certain high-lift cams and high-compression engines).

The alignment marks are found on the pulleys and on the backing plates or block behind them: Camshaft (Top): Mark is nearly at 12 o'clock. The pulley groove is aligned with the mark on the backing plate. Crankshaft (Bottom): Mark at 12 o'clock. The crankshaft sprocket groove is aligned with the vertical mark on the block. Auxiliary shaft (Right): Mark approximately at 3 o'clock.

This depends on the distributor location: Distributor on block (e.g., 240-series): The auxiliary shaft mark must be aligned, since the auxiliary shaft drives the distributor. If the mark is off, ignition timing will be scrambled. Distributor on head (e.g., 740/940-series): The auxiliary shaft position is not critical, since it only drives the oil pump in this case.

Preparation: Remove the fan blades, water pump pulley, and drive belts. Ease rotation: Remove the spark plugs so the engine is easy to turn by hand to the marks. Disassembly: Remove the timing head covers and loosen the tensioner roller. Replacement: Install the new belt, ensuring the pulleys do not move from their marks. Tensioning: Release the tensioner roller, allowing the spring to tension the belt to the correct tightness. Tighten the roller nut.

Re-tensioning: It is recommended to check the belt tension and perform re-tensioning after approximately 1000 km of driving. Part replacement: With the effort already invested, it is wise to also replace the tensioner roller and check the water pump and crankshaft seal for leaks.