What is the Timing Chain all about?
Your engine is made up of hundreds of moving components that need to move in sync to make your engine run. The timing chain joins the crankshaft in the lower end of the engine to the camshaft in the upper part of the engine so they turn together. It is made up of metal links and moves on toothed sprockets on the end of the camshaft and crankshaft. On vehicles with variable valve timing, small actuators and motors advance and retard the timing to compensate for economy or performance in varying situations. In cases where the timing chain has stretched, you may experience a rattle from the engine or a lack of responsiveness when accelerating. In extreme cases, the engine may stall while driving or not start.
Keep in mind:
- Replace worn timing chain guides at the same time as the timing chain.
- Replace balance shaft chains along with the timing chain if equipped.
How it's done:
The timing chain is verified as defective or broken. The vehicle is lifted and supported on jack stands. The coolant and oil is drained.
The water pump, belt and accessories are removed to gain access for the timing chain. Oil pan is lowered.
The timing cover is removed and the engine timing marks are aligned. The timing gears, chain and guides are replaced with new ones. The timing cover is reinstalled.
The oil pan is reinstalled. The water pump, belt and accessories are re-installed as required. The engine oil and coolant are filled. The vehicle is removed from the jack stands.
The engine is started and the ignition timing is checked and adjusted as needed. The vehicle is road tested for proper operation.
Unlike a vehicle equipped with a timing belt, the timing chain is not a regular maintenance item and only needs to be replaced when symptoms are present. Should the timing chain need to be changed, replace any timing chain guides that are worn, any variable valve timing actuators or motors that are out of spec, and balance shaft chains. The labor cost to replace these parts is higher than the cost of the parts and replacing them at the same time as the timing chain can prevent future breakdowns.
What common symptoms indicate you may need to replace the Timing Chain?
- Check Engine light is illuminated
- Rattle from the engine compartment at idle
- Loss of acceleration and responsiveness
- Engine will turn over but not start
How important is this service?
The timing chain is a major component in your engine. A timing chain that is not addressed in a timely fashion can create additional problems that will incur extra costs if a breakdown occurs. If the timing chain is stretched badly, your vehicle can stall in traffic causing a hazard to you and the vehicles around you.