1999-2001 Frontier and Xterra Right-Hand Exhaust Manifolds Cracked in VGS33E Engines - Engine Builder Magazine

1999-2001 Frontier and Xterra Right-Hand Exhaust Manifolds Cracked in VGS33E Engines

If a cracked right-hand exhaust manifold on a 1999-2001 Nissan VGS33E engine is discovered when the exhaust
heat shield is removed, installers must replace the exhaust manifold.

If one of these symptoms should occur, use the following to diagnose
the condition, replacing the right-hand exhaust manifold and related
parts as described.

 

SERVICE PROCEDURE

Diagnosis:

1. Installers should verify the source of the noise with the engine running that it is coming from the right-hand manifold area.

 

2. If the noise is coming from the right-hand manifold area, remove the
heat shield and inspect for cracks between the #1 and #3 ports on the
manifold.

 

Repair:

1. Separate the catalyst from the right-hand exhaust manifold and remove it to allow for clearance.

 

Caution: The nuts that attach the catalyst to the exhaust manifold have
a self-locking design and require some effort to remove. Apply
penetrating oil to the threads and allow it to soak in before
attempting to remove the nuts.

 

Use a tight-fitting six-point socket to avoid rounding off the corners
of the nuts during removal. If any of the nuts or studs are damaged
during removal, replace them as needed.

 

2. Remove the exhaust manifold from the head (See Figure 2A for loosening sequence of manifold nuts). NOTE: If any of the nuts or studs are damaged during removal, replace them as needed.

 

3. Install the replacement manifold with a new gasket onto the head. See Figure 2B for tightening sequence of manifold nuts. See Figure 1 for manifold nut torque specifications.

 

4. Re-attach the catalyst to the exhaust manifold. NOTE: Ensure that
all bolts securing the manifold and heat shields are installed and are
torqued to the specifications shown in Figure 1.

 

5. Installers should test-drive the vehicle to verify the ticking or exhaust noise has been eliminated.

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.
figure 1figure 2aFigure 2B

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