GM Full-Size Trucks 1970-1979 Repair Guide

Exhaust Manifold

Print

REMOVAL & INSTALLATION



Inline 6-Cylinder Engines

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Exhaust manifold tightening sequence - 1975 and later inline 6-cylinder engines with integral intake manifold/cylinder head

1974 and earlier inline 6-cylinder exhaust manifold removal and installation procedures are covered under the Intake Manifold procedure (both manifolds are a unit). 1975 and later inline 6-procedures are covered below.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly, including the carburetor preheat tube.
  4.  
  5. Disconnect the exhaust pipe from the exhaust manifold. You will probably have to use a liquid rust penetrant to free the bolts.
  6.  
  7. Remove the engine oil dipstick bracket bolt.
  8.  
  9. Liberally coat the manifold nuts with a rust penetrating lubricant. Remove the exhaust manifold bolts and remove the manifold.
  10.  
  11. To install, mount the manifold on the cylinder head and start all bolts.
  12.  
  13. Tighten the bolts to specification using the tightening sequence illustrated. Complete the installation by reversing the removal procedure.
  14.  

Gasoline V6 and V8s

See Figures 2 and 3



Click image to see an enlarged view

Fig. Fig. 2: View of the plastic manifold gasket retainers used on gasoline V8 engines



Click image to see an enlarged view

Fig. Fig. 3: Common exhaust manifold with hot air shrouds - gasoline V8 engines

Tab locks are used on the front and rear pairs of bolts on each exhaust manifold. When removing the bolts, straighten the tabs from beneath the car using a suitable tool. When installing the tab locks, bend the tabs against the sides of the bolts, not over the top of the bolt.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner.
  4.  
  5. Remove the hot air shroud, (if so equipped).
  6.  
  7. Loosen the alternator and remove its lower bracket.
  8.  
  9. Jack up your car and support it with jack stands.
  10.  
  11. Disconnect the crossover pipe from both manifolds.
  12.  
  13. Lower the vehicle.
  14.  

On models with air conditioning it may be necessary to remove the compressor, and tie it out of the way. Do not disconnect the compressor lines.

  1. Remove the manifold bolts and remove the manifold(s). Some models have lock tabs on the front and rear manifold bolts which must be removed before removing the bolts. These tabs can be bent with a drift pin.
  2.  
  3. Reverse the above to install. Tighten the bolts to specifications and bend the tab washers over the heads of all bolts.
  4.  

350 Diesel V8
LEFT SIDE
  1. Remove the air cleaner and cover the air crossover with a protective plate, screen or cover.
  2.  
  3. Remove the lower generator bracket.
  4.  
  5. Jack up the truck and safely support it with jackstands.
  6.  
  7. Remove the exhaust pipe at the manifold flange.
  8.  
  9. Lower the truck.
  10.  
  11. Remove the exhaust manifold from above.
  12.  
  13. Reverse the above procedure to install. Tighten the manifold nuts and bolts according to the illustration.
  14.  

RIGHT SIDE
  1. Jack up the truck and safely support it with jackstands.
  2.  
  3. Disconnect the exhaust pipe at the manifold flange.
  4.  
  5. Remove the manifold.
  6.  
  7. Reverse the above procedure to install, tightening the manifold bolts according to the accompanying illustration.
  8.  

 
label.common.footer.alt.autozoneLogo