Your engine’s timing system is one of its most important components, but also one of the least understood. Whether your 4WD uses a timing belt or a timing chain, both require regular maintenance to keep the engine running safely and reliably.
Timing Belts 101
A timing belt synchronises the engine’s crankshaft and camshaft(s), keeping valves opening and closing at exactly the right time. Because timing belts are made of reinforced rubber, they wear out over time, become brittle from heat, and can crack, split or stretch under load.
Replacement intervals: Most modern 4WDs require belt replacement around 100,000–150,000 km, or every 5–7 years — whichever comes first. Touring, towing, and QLD heat can accelerate wear.
A proper timing belt kit includes the belt, tensioner, idler pulleys, water pump (on many models), and fresh coolant.
Timing Chains 101
Timing chains are metal and run inside the engine, lubricated continuously. They are designed to last longer, but they are not “lifetime” components.
Chains can suffer from stretching, tensioner wear, guide wear, oil starvation, and rattling on cold starts. Poor oil quality or skipped servicing is the number one reason chains fail.
Warning Signs
Timing Belt:
- Ticking noise from the engine
- Trouble starting
- Visible cracks during inspection
- Coolant leaks around the water pump
- Engine vibration under load
Timing Chain:
- Rattling on a cold start
- Loss of power
- Check engine light
- Excessive soot or smoke
- Metallic noise at idle
What Happens If They Fail?
Most diesel engines are interference engines. If the belt or chain fails, pistons can strike valves, valves bend, and the engine can become a write-off. Repairs often exceed $5,000–$15,000 depending on the vehicle.
BB Garage’s Timing System Approach
- Inspection of all timing components
- Assessment of service history (kilometres and age)
- Water pump inspection
- Quality manufacturer-approved or high-quality kits
- Honest recommendations — no upsells, no scare tactics
Book a timing belt or timing chain inspection with BB Garage today.
