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Installing a 2003 Silverado Exhaust Manifold

The 2003 Chevy Silverado base model came with a 4.3-liter V-6 and a five-speed manual transmission. The exhaust manifolds are the link between the cylinder head and exhaust piping, and provide a direct path for the exhaust to exit the engine. Exhaust manifolds commonly need to be replaced because of cracking, excessive corrosion or warping of the mating surface. Because the 4.3 has two cylinder heads there are also two exhaust manifolds, each of which has its own procedure for replacement.

Instructions

Right Exhaust Manifold Removal

1

Park the truck on a level surface and set the parking brake. Lift the front of the truck into the air with the floor jack and place the jack stands under the front frame rails of the vehicle. Lower the floor jack until the vehicle rests securely on the jack stands. Allow the engine to cool completely before continuing.

2

Lay down under the vehicle and locate the flange for the right exhaust manifold and downpipe mating area. Remove the three mounting nuts with the socket and ratchet.

3

Loosen the clamps for the air intake hose at the intake manifold and mass airflow sensor with the screwdriver. Disconnect the positive crankcase ventilation tube and remove the air cleaner adapter nut. Tilt the air cleaner tube upward to release the hinge and remove the air cleaner tube from the engine.

4

Label and disconnect the three right spark plug wires. Remove the spark plug wire retainer bolt with the socket and ratchet. Position the spark plug wires on top of the engine, marking them with tape to ensure proper placement when you reinstall them. Remove the spark plugs with the spark plug socket and ratchet.

5

Remove the engine oil dipstick and set it aside. Follow the bracket that is welded to the top of the tube to its mounting position on the cylinder head. Remove the dipstick tube bolt with the socket and ratchet. Lift the dipstick tube out of the engine block with a slight twisting motion. Wipe off any thread sealant and set the dipstick tube aside.

6

Remove the exhaust manifold and the spark plug heat shield bolts. Remove the spark plug heat shields and set aside. Remove the exhaust manifold and exhaust manifold gaskets. Clean the exhaust manifold mating surface on the cylinder head with the wire brush. Clean any leftover sealant from the dipstick tube hole with a shop rag.

Right Exhaust Manifold Installation

7

Install the new exhaust manifold gaskets to the exhaust manifold. Place the exhaust manifold into position followed by the spark plug heat shields and exhaust manifold bolts. The tabs in the gasket should hold everything in place to aid in installation.

8

Apply the threadlock compound to the threads of the exhaust manifold bolts. Set the exhaust manifold into position and tighten the mounting bolts, in an alternating pattern, 22 foot-pounds with the torque wrench. Inspect the spark plugs for excessive wear or corrosion and replace as necessary. Check the spark plug gap and ensure its set at 0.060-inch with the spark plug gap tool.

9

Thread the spark plugs into the cylinder head by hand and then tighten to 11 foot-pounds with the spark plug socket and torque wrench. Position the spark plug wire retainer and loosely install the bolt. Connect the spark plug wires to their respective spark plugs based on the markings made previously. Remove the tape from the plug wires. Place a small amount of pipe sealant on the base of the tube and Install the oil level indicator tube by pushing it into its hole in the crankcase. Install the dipstick tube bracket bolt to the cylinder head and tighten to 106 inch-pounds. Tighten the plug wire bracket bolt to 106 inch-pounds.

10

Align the hinge clip with the lip on the throttle body opening and rotate the air cleaner tube downward until the stud pushes through the mounting hole. Install the air cleaner adapter nut. Direct the air intake tube to the MAF sensor and tighten the mounting clamp. Connect the PCV tube to the air intake tube.

11

Lay down under the vehicle and install the new gasket to the downpipe and install the manifold retaining nuts. Tighten the down pipe to manifold maintaining nuts in an alternating pattern to 37 foot-pounds with the torque wrench.

12

Lift the vehicle off the jack stands with the floor jack and remove the jack stands from under the vehicle. Lower the vehicle to the ground and remove the floor jack.

Left Exhaust Manifold Removal

13

Park the truck on a level surface and set the parking brake. Lift the front of the truck into the air with the floor jack and place the jack stands under the front frame rails of the vehicle. Lower the floor jack until the vehicle rests securely on the jack stands. Allow the engine to cool completely before continuing.

14

Lay under the vehicle and locate the flanged connection for the exhaust manifold and exhaust down pipe. Remove the retaining nuts with the socket and ratchet.

15

Mark and label each of the spark plug wires with the tape to aid in installation. Disconnect the spark plug wires from each spark plug. Remove the spark plug wire retaining bolts with the socket and ratchet. Move the plug wires to the top of the engine and out of the way.

16

Remove the spark plugs with the spark plug socket and ratchet. Disconnect the coolant temperature sensor connector and put it aside. Remove the exhaust manifold and spark plug shield bolts and stud with the socket and ratchet. Remove the spark plug shields followed by the exhaust manifold. Remove and discard the exhaust manifold gaskets.

Left Exhaust Manifold Installation

17

Clean the mating surface at the cylinder head with the wire brush. Place the new manifold gasket onto the exhaust manifold and set the spark plug head shields into place. Place the manifold and heat shield bolts through the holes on the manifold; the new gasket should hold everything together.

18

Coat the exhaust manifold bolt threads with the threadlock compound and install the manifold to the cylinder head. Tighten the mounting bolts, in an alternating pattern, to 22 foot-pounds with the torque wrench. Connect the coolant temperature harness to the coolant temperature sensor.

19

Install the spark plugs into the cylinder head by hand. Tighten the spark plugs to 11 foot-pounds with the torque wrench. Place the spark plug retainer into position and install the retaining bolts, tightening them to 106 inch-pounds with the torque wrench.

20

Connect the spark plug wires to their respective plugs according to the tape markings on the plug wires. Remove the tape from the spark plug wires.

21

Lay down under the vehicle and install the new doughnut gasket to the exhaust manifold downpipe. Set the downpipe and exhaust manifold into position and install the mounting nuts. Tighten the nuts, in an alternating pattern, to 37 foot-pounds with the torque wrench.

22

Lift the vehicle off the jack stands with the floor jack and remove the jack stands from under the vehicle. Lower the vehicle to the ground and remove the floor jack.

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Labels: 2003, a, exhaust, installing, manifold, silverado