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When should I replace my timing chain? brake fluid system?
A stretched timing chain can skip a tooth on the camshaft or crankshaft gear, affecting valve timing.
PHOTO | SHUTTERSTOCK
What you need to know:
- A stretched timing chain can skip a tooth on the camshaft or crankshaft gear, affecting valve timing
Hello Paul, I drive a 2003 Toyota Camry with a 2AZ-FE engine. Recently, my engine has started making a rattling noise when I start it, especially in the morning. The noise is becoming more noticeable, and I have also experienced a loss of engine power, unstable idling, and a check engine light appearing on the dashboard. My service technician says I may need to replace the timing chain to prevent further engine damage. However, I was under the impression that only timing belts require replacement. Could you please advise me on this matter? Kakande
Hello Kakande, timing chains and timing belts serve the same purpose; they synchronise the opening and closing of valves in the cylinder head while ensuring the pistons move correctly within the combustion chamber. This synchronisation prevents any damaging collisions between fast-moving metallic valves and pistons. A failure of either component can result in catastrophic engine damage.
Unlike timing belts, which require replacement at specified intervals (typically around 100,000 km or 60,000 miles), timing chains are designed to last much longer and operate inside the engine, where they are lubricated by engine oil. However, over time, they can wear out due to poor lubrication or prolonged use. The symptoms you are describing suggest possible timing chain wear or failure, including:
Engine misfire:
A stretched timing chain can skip a tooth on the camshaft or crankshaft gear, affecting valve timing. This disrupts the air intake and compression process, leading to poor performance, erratic idling, and engine misfires. In advanced cases, the engine may struggle to start or stall unexpectedly.
Metal shavings in oil:
A failing timing chain can produce small metal shavings that accumulate in the engine oil. These may be visible in the oil drained during service. Such shavings could also indicate wear on cylinder head valves or piston rings due to inadequate lubrication.
Rattling noise:
One of the most common warning signs of a failing timing chain is a rattling noise during cold starts. A healthy engine should run smoothly, but a loose or worn-out chain creates vibrations, leading to this distinct noise.
This symptom requires urgent attention, as it may indicate that the chain is on the verge of breaking, which could result in severe engine damage.
Replacing a timing chain is a labour-intensive process, typically taking six to eight hours. It is essential to have this job done by an experienced mechanic using a high-quality timing chain replacement kit and following manufacturer guidelines for timing marks.
Proper replacement will restore your engine’s performance, improving fuel economy and power delivery.
To extend the lifespan of your timing chain, always use high-quality engine oil that meets manufacturer specifications and genuine original equipment manufacturer oil filters.
