Chevrolet Cobalt Service & Repair Manual: Valve Spring Replace

This procedure is designed to replace valve spring while head is attached to engine.
1. Install a suitable flywheel holding tool in order to prevent crankshaft rotation.
2. Remove applicable spark plug from cylinder head.
3. Install a suitable spark plug port pneumatic adapter to applicable cylinder.
4. Connect spark plug port adapter to a compressed air source.
5. On models equipped with overhead camshaft, proceed as follows:
  a. Remove camshaft from cylinder head as outlined in "Camshaft, Replace."
  b. Remove valve lifter cap.
  c. Remove valve lifter cap shims if required. Ensure that shims stay with respective lifter caps and are not mixed together.
6. On models without overhead camshaft, remove valve rocker assembly.
7. On all models, tap end of valve stem with a plastic face hammer in order to loosen any varnish on valve stem keys.
8. Compress valve spring using a suitable valve spring compressor.
9. Remove valve stem keys.
10. Release valve spring compressor tension.
11. Remove valve spring cap.
12. Remove valve spring.
13. Remove spring seat shims, if equipped.
14. Reverse procedure to install, note following:
  a. Tap end of valve stem with a plastic faced hammer to seat keys, if required.
  b. Measure valve spring installed height using a ruler. If installed height exceeds manufacturer recommendation, install appropriate spring shims.
  c. On models equipped with overhead camshaft, install camshaft as outlined in "Camshaft, Replace."
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    See also:

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