How to Change an Exhaust Manifold on a 1997 Chevy S-10. The first Chevy S-10 was produced for the 1982 model year, and it didn't see a second generation until 1994. In 2003 – only nine years later – the long-lived S-10 was discontinued by Chevy. The S-10 had a wide variety of engines available in its first few years, but by the second generation Chevy offered the S-10 with only two; the 2.2-liter four-cylinder and the Vortec 4.3-liter V-6. Replacing the exhaust manifolds on either engine is straightforward, but there are slight differences in the procedures between the two engines.
Open your S-10's hood. Lift the front end with a floor jack and place jack stands under the front frame rails. Lower your S-10 onto the jack stands. Loosen the air intake clamp at the air box and before the bend to the throttle body with a screwdriver. Remove the air intake tube from the engine bay.
Squeeze the locking tab on the oxygen-sensor pigtail and separate it from the engine wiring harness. Let the pigtail hang down for now. Lie under the vehicle and remove the oil dipstick retaining bolt from the engine block, using a socket and ratchet. Remove the manifold to down-pipe nuts – use an open-end wrench to hold the bolts steady.
Pull the oil dipstick out of the crankcase and through the manifold. Wipe up and oil drops with a shop towel. Remove the manifold-to-cylinder-head nuts. Pull the manifold off of the head studs and lift it out of the engine bay. Remove the manifold-to-cylinder-head gasket. Remove the manifold to down pipe gasket.
Spray the base of the oxygen sensor with penetrating oil. Remove the oxygen sensor from the manifold with an oxygen-sensor socket and ratchet. If the oxygen sensor is difficult to break loose, clean all of the penetrating oil off of the sensor and apply heat with a propane torch to the manifold around the oxygen sensor.
Clean the manifold mating surface on the cylinder head with a wire brush. Install a new manifold gasket to the cylinder head. Install the manifold onto the cylinder head and install the mounting nuts. Tighten the nuts to 11 foot-pounds with a torque wrench, then tighten them to 22 foot-pounds.
Clean the oxygen-sensor threads with a wire brush, then install a coat of anti-seize compound to the threads. Install the oxygen sensor to the exhaust manifold and tighten it to 31 foot-pounds. Guide the oil dipstick through the exhaust manifold and into the crankcase.
Tighten the dipstick bolt snug with a socket and ratchet. Install a new gasket to the down pipe and guide the down pipe onto the exhaust manifold. Slide the bolts through the manifold flange and into the down pipe. Install the nuts and tighten them to 18 foot-pounds.
Lift the front of the truck off the jack stands and remove them. Lower the truck to the ground. Install the air intake tubing and tighten the band clamps. Connect the oxygen-sensor pigtail to the wiring harness.
Lift the truck and remove the air intake tubing according to Step 1 in the section titled “2.2-liter Exhaust Manifold Replacement.”
Remove the oil-dipstick-retaining bolt with a socket and ratchet. Remove the manifold-to-Y-pipe nuts for both exhaust manifolds – use and open-end wrench to hold the bolts steady.
Group the left spark plug wires together with masking tape, then do the same for the right plug wires. Label the individual spark-plug wires with masking tape and a permanent marker – the best idea is to number each plug wire from front to rear.
Remove the plug wires from each spark plug and position them aside – do not remove them from the distributor. Remove the spark plugs with a spark-plug socket and ratchet. Remove the heat shields. Disconnect the oxygen-sensor pigtails from the wiring harness. Remove the exhaust-gas-recirculation tube from from the manifold and EGR valve with an open-end wrench – the tube nuts loosen counterclockwise.
Place mechanic's wire though the under-hood paneling and wrap it around the exhaust manifold. Remove the manifold to cylinder head bolts. Pull the exhaust manifold off of the cylinder head and remove the mechanics wire. Lift the manifold out of the engine bay. Repeat this step for the opposite manifold.
Remove the oxygen sensor from each manifold with an oxygen-sensor socket and ratchet – use a torch to heat the manifold around the sensor, if necessary.
Remove the manifold to head gaskets and clean both cylinder heads with a wire brush. Clean the oxygen-sensor threads with a wire brush and apply a coat of anti-seize to the threads. Install the oxygen sensor to each manifold and tighten them to 31 foot-pounds.
Install new exhaust manifolds and gaskets to both cylinder heads. Install the mounting bolts and tighten them to 11 foot-pounds on the first pass, then 22 foot-pounds on the second. Guide the oil dipstick through the right exhaust manifold and into the crank case.
Install the dipstick mounting bolt and tighten it snug. Install new gaskets to the exhaust manifolds and secure the y-pipe to the manifolds with the nuts and bolts. Tighten the nuts to 18 foot-pounds. Lift the front of the truck off the jack stands and lower it to the ground.
Install the EGR tube to the EGR valve and left exhaust manifold. Tighten the tube nuts with an open-end wrench. Connect the oxygen-sensor pigtails to the wiring harness.
Inspect the spark plugs for carbon build up or fouling and replace them as necessary. Set the gap on each spark plug to 0.060-inches with a gap tool. Install the heat shields for each spark plug to the cylinder head and exhaust manifold. Install the spark plugs and tighten them to 15 foot-pounds. Install the spark-plug wires to each spark plug according to the labels you made previously. Remove the masking tape. Install the intake tubing and tighten the band clamps.