Cylinder heads. Piston and connecting rod

Cylinder heads



To ensure engine gasket sealing, proper surface preparation must be performed, especially with the use of aluminum engine components.

Never use the following to clean gasket surfaces:

  • never use a metal scraper
  • never use an abrasive pad or paper to clean the cylinder block.
  • never use a high speed power tool or wire brush on any gasket sealing surface (Fig. 136).

Only use the following for cleaning gasket surfaces:

  • use Mopart Brake and Parts Cleaner
  • use only a plastic or wood scraper (Fig. 136)

Fig. 136 Proper Tool Usage For Surface Preparation Fig. 136 Proper Tool Usage For Surface Preparation



(1) Inspect the cylinder head for out-of-flatness, using a straightedge and a feeler gauge. If tolerances exceed 0.0508 mm (0.002 in.) replace the cylinder head.

(2) Inspect the valve seats for damage. Service the valve seats as necessary.

(3) Inspect the valve guides for wear, cracks or looseness. If either condition exist, replace the cylinder head.

Piston and connecting rod


CAUTION: DO NOT use a wire wheel or other abrasive cleaning devise to clean the pistons or connecting rods. The pistons have a Moly coating, this coating must not be damaged.

(1) Using a suitable cleaning solvent clean the pistons in warm water and towel dry.

(2) Use a wood or plastic scraper to clean the ring land grooves.

CAUTION: DO NOT remove the piston pin from the piston and connecting rod assembly.


Check the crankshaft connecting rod journal for excessive wear, taper and scoring.

Check the pistons for taper and elliptical shape before they are fitted into the cylinder bore.

Replace any piston and connecting rod not meeting the specifications.

    Dodge Durango (DN) 1998-2003 Service Manual


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