Mechanics

Timing Chain Replacement

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Timing Chain and Camshaft Gear
How to Replace a Timing Chain

Your engine has different components that need to work together at the same time for the engine to run properly. The timing chain is one such component. The timing chain is responsible for timing between the crankshaft and the camshaft. The camshaft relies on the timing chain to turn so it can drive the lifters, push rods and open and close the valves at specific times. Although the timing gears and chain are very durable, over time, the chain can stretch and the gears can wear. As a result, the valves can open and close at slightly different times causing different problems for the engine.

The most common signs of a worn timing chain and gears is a rough idle, poor fuel economy, poor performance, noise from the timing chain area, and in extreme circumstances, the engine may not start. These problems can lead to more involved internal problems if the chain isn’t replaced.

Parts and Supplies needed to Replace a Timing Chain

1 - New timing chain and gears

2 - Timing chain cover gasket set

3 - Coolant

4 - Protective clothing

5 - Eye protection

Tools Needed to Complete this Job

1 - Sockets and socket wrench

2 - Scraper

3 - Screw drivers

4 - Puller for a harmonic balancer

5 - Drain pan

6 - Jack and Jack stands

7 - Torque wrench

8 - Shop towels

Crankshaft Gear and Timing Chain
Instructions

Step 1 - Park the vehicle on a flat location, place it in park (AT) or in reverse (MT), apply the parking brake, open the hood, disconnect the negative battery terminal, and allow the engine to cool.

Step 2 - After the engine cools, drain the coolant from the radiator into the drain pan.

Step 3 - Remove all belts from engine.

Step 4 - Next, remove the upper and lower radiator hoses and any heater core hoses that are attached to the water pump.

Step 5 - At this point, remove the fan and clutch fan from the water pump. If you only have an electric fan and it doesn’t obstruct the front of the engine, it can remain in place.

Step 6 - Locate the bottom pulley on the crankshaft. Unbolt the pulley from the harmonic balancer and using your harmonic balancer puller, remove the harmonic balancer. NOTE: There will be a shear key between the balancer and the crankshaft. Make sure not to lose it.

Step 7 - Now, remove the retaining bolts from the timing chain cover. NOTE: On many engines, you need to remove the front two or four bolts from the oil pan for the cover to come loose.

Step 8 - Once you remove the timing chain cover, clean and identify the timing marks on the crankshaft and camshaft. Align them according to the manufacturer’s recommendations for your engine. This will help when replacing the new parts.

NOTE: Once the chain is removed, make sure not to move the crankshaft or camshaft. This is also a good time to remove all old gasket material from both the engine block and the timing chain cover.

Step 9 - Once you have the marks aligned, remove the bolts from the camshaft sprocket and slide the sprocket away from the camshaft. Do the same with the crankshaft sprocket.

Step 10 - Install the new crankshaft gear making sure the timing mark is facing outward and pointing the same direction as the old one.

Step 11 - Next, install the new camshaft sprocket and chain at the same time. Make sure the timing marks are in the correct positions according to the manufacturer’s recommendations for your specific engine. Once in place, replace the camshaft sprocket bolts and properly torque them.

Step 12 - If you have cleaned all old gasket material from the engine and timing chain cover, check your new gasket kit. Many include a new seal for the crankshaft. If you have one, remove the old seal from the cover and carefully install the new one. NOTE: Use a block of wood to tap it into position. DO NOT use only a hammer. It will damage the new seal. Once the seal is installed, place a thin coating of oil on the lip of the seal.

Step 13 - Now it is time to reinstall the timing chain cover with the new gasket. Carefully install it and hand tighten the retaining bolts.

Step 14 - Torque the bolts to the manufacturer’s recommendations and don’t forget to tighten the front oil pan bolts if they were loosened.Step 15 - Reinstall the harmonic balancer and the pulley and torque to the manufacturer’s specifications.

Step 16 - Reinstall the water pump and all accessories that you removed from the front of the engine. Make sure to properly tighten everything as you go through this process.

Step 17 - Install belts, radiator hoses and heater hoses.

Step 18 - Once everything is back together, refill the radiator with coolant. Make sure to tighten the drain plug before starting to refill.

Step 19 - Replace the negative battery terminal, start the engine, and allow it to warm up to operating temperature.

Step 20 - Once the engine is warm, check for leaks.

Step 21 - Based on the year of your vehicle, you may need a timing light to check ignition timing. Most newer vehicle timing is adjusted by the vehicle’s computer.

Best Practices

  • Avoid allowing gasket material, dirt, and coolant from getting into the engine
  • When replacing a timing chain, always replace the gears
  • Always double check the timing marks are correct
  • Always place a thin coating of oil on new seals before they are installed
If further technical assistance is needed, our certified car repair technicians are ready to answer your car questions. For manufacturer specific repair information visit - Car Repair Manuals

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AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-08-16)