How to Replace the Timing Chain on a 1994 Saturn

Changing the timing chain on a 1994 Saturn is a complicated process that only mechanics with some automotive-repair experience and engine component knowledge should attempt. The timing chain can be replaced in a few hours with the help of an assistant and a close eye when installing the sprockets and timing chain. An assistant is necessary only for the first step in this guide, but will also be useful to help you during the rest of the process.

Removing the Timing Chain

Set the Top Dead Center position for the number one piston. Remove the spark plug wires, pulling the boot off of each spark plug. Place the car in neutral. Attach a socket to the bolt threaded onto the camshaft vibration damper. Put a finger over the number one spark hole, which is the hole located closest to the timing chain end of the engine. While holding your finger over the hole, have an assistant rotate the socket on the vibration damper clockwise. When you can feel air pressure on your finger, have the assistant stop rotating the damper. Place a drinking straw into the hole and begin rotating the damper slowly, which while bring the piston up and force the straw up from the hole. Keep rotating the damper until the straw fails to rise. When the straws fails to rise, the number one piston is at Top Dead Center position.

Place an automotive jack under the front of the vehicle and raise it, placing jack stands under the frame to support it. Remove the jack once the vehicle is supported by the stands.

Drain the engine oil. Place a engine fluid container under the oil drain fitting on the bottom of the engine block. Loosen the fitting with a wrench until fluid flows into the container. Tighten the fitting when fluid has finished draining.

Remove the passenger-side lug nuts holding the front wheel in place with a socket wrench and remove the wheel.

Remove the splash shield from inside the passenger-side front fender. Use wire cutters to pull up the center of the fasteners. Do not use force when pulling up the plastic centers to ensure they aren't cut. Pull the shield away from the fender once the fasteners are removed.

Remove the crankshaft vibration damper and pulley. Place a pry bar through the damper and slip the end under the engine block to hold the damper in place. Remove the damper retaining bolt with a socket wrench. Place a crankshaft puller on the shaft and remove the damper and pulley.

Remove the accessory belt tensioner. Place a socket wrench on the bolt on the center of the tensioner pulley and turn it counterclockwise to remove the bolt and pulley. Remove the two tensioner bracket bolts with a socket wrench and remove the tensioner.

Remove the three water pump pulley bolts with a socket wrench and remove the pulley.

Place a block of wood on the automotive jack and place the jack under the engine oil pan. Gently raise the engine, gaining just enough room to access the timing chain cover on the passenger side of the engine.

Remove the four bolts holding the oil pan to the timing chain cover with a socket wrench, then remove the rest of the remaining timing chain cover bolts.

Remove the timing chain cover. Place a large socket over the crankshaft to keep the front crankshaft seal in place while pulling the timing chain cover slightly away from the engine block. Once the cover has been moved an inch away from the block, remove the socket and pull the cover from the block.

Remove the sprockets, tensioner and timing chain guides. Remove the two bolts holding the tensioner in place with a socket wrench and remove the tensioner. Remove the bolts holding the guides in place and remove the guides. Place a mark on both sprockets to ensure they are installed in the same position. Ensure the sprockets do not remove while removing the retaining bolt on both the camshaft and crankshaft sprockets. Remove the retaining bolts and remove both sprockets and chain.

Installing the Timing Chain

Install the camshaft sprocket temporarily, placing the sprocket onto the shaft without the retaining bolt, using the marks made previously to install it in the same position from which it was removed. If the sprockets have not been turned since setting the Top Dead Center position for the number one piston, the dimple on the sprocket should be at the 12 o'clock position. Use the long end of an Allen wrench, sticking it through the small hole at the top of the sprocket and placing it through the alignment hole on the cylinder head. This will ensure the camshaft sprocket is properly aligned.

Place the crankshaft sprocket onto the shaft, using the marks made before removal for installation. Turn it 90 degrees to align the dimple on the crankshaft with the mark on the engine block, which should be at 6 o'clock.

Remove the camshaft sprocket slightly and place the timing chain over the camshaft sprocket. One of the bright links on the timing chain will be installed over the dimple on the camshaft sprocket tooth at the 12 o'clock position.

Place the timing chain over the crankshaft sprocket. One of the bright links on the timing chain will be installed over the dimple on the crankshaft sprocket tooth at the 6 o'clock position.

Place the camshaft sprocket onto the shaft and install the camshaft sprocket bolt with a torque wrench, tightening it to 75 foot-pounds, ensuring the sprockets do not rotate during installation.

Lubricate the timing chain guides with engine grease.

Place the timing chain guides into position and replace the mounting bolts with torque wrench, tightening the bolts to 19 foot-pounds.

Compress the plunger on the tensioner all the way into the tensioner and put the tensioner in place, keeping the plunger compressed during installation. Install the two tensioner mounting bolts with a torque wrench, tightening them to 168 inch-pounds.

Clean the mating surfaces of the timing cover and engine block with a gasket scraper and a towel soaked in acetone.

Place a coat of RTV sealant approximately 2 mm thick over the timing chain cover. Place a coat of RTV sealant approximately 4 mm thick to the front of the oil pan.

Place the timing chain cover against the engine block and install the timing chain cover bolts with a torque wrench, tightening the lower-center bolt to 89 inch-pounds, the upper bolts to 22 foot-pounds and the other bolts to 19 foot-pounds.

Place the camshaft vibration damper/pulley onto the shaft and install the retaining bolt, tightening the bolt with a torque wrench to 159 foot-pounds.

Lower the automotive jack supporting the engine.

Place the water pump pulley onto the water pump and install the three water pump pulley bolts with a socket wrench.

Place the accessory belt tensioner bracket against the engine block and install the two mounting bolts with a socket wrench. Place the tensioner pulley onto the bracket and install the pulley mounting bolt. Place the belt over the pulley and tighten the tensioner, tightening the tensioner pulley bolt with a wrench.

Place the splash shield under the fender and push the fasteners into the holes on the fender and splash shield. Push the centers of the fasteners in to engage them.

Place the wheel onto the wheel studs and install the lug nuts with a torque wrench, tightening the lug nuts to 100 foot-pounds.

Support the vehicle with an automotive jack, remove the jack stands and lower the vehicle.

Fill the vehicle with engine oil, using the dipstick to check for the appropriate level.