C2.4 Tier 4 Final Engines for Caterpillar Built Machines Caterpillar

Note: Checking the valve lash should be done every 1000 hours. Refer to the Operation and Maintenance Manual, Maintenance Interval Schedule for more information.

Probable Causes

• Valve lash setting is not within specifications

• Worn rocker arms

• Worn valve springs or broken valve springs

• Bent pushrods

• Worn camshaft

• Valve seat wear

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

Table 1

Troubleshooting Test Steps	Values	Results
1. Valve Lash Setting A. Check the engine valve lash. If necessary, adjust the engine valve lash. Refer to Systems Operation/Testing and Adjusting for information on adjusting the engine valve lash.	Valve lash	Result: The valve lash is set to specifications. Return the unit to service. Result: The valve lash cannot be set to specifications. Proceed to Test Step 2.
2. Rocker Arms A. Inspect rocker arms for pitting or spalling on the roller. B. Check the rocker arm for a missing button.	Rocker arms	Result: The rocker arms are not damaged. Proceed to Test Step 3. Result: The rocker arms are damaged. Replace parts, if necessary. If the symptom remains, proceed to Test Step 3. If the problem has been corrected, return the unit to service.
3. Valve Springs A. Check for cracked valve springs or broken valve springs.	Valve springs	Result: The valve springs are not broken or cracked. Proceed to Test Step 4. Result: The valve springs are broken or cracked. Replace parts, if necessary. If the symptom remains, Proceed to Test Step 4. If the problem has been corrected, return the unit to service.
4. Pushrods A. Check the pushrods for wear and straightness. B. Roll the pushrods on a flat surface to determine the straightness of the rod.	Pushrods	Result: The pushrods are not worn or bent. Proceed to Test Step 5. Result: The pushrods are worn or bent. Replace parts, if necessary. If the symptom remains, Proceed to Test Step 5. If the problem has been corrected, return the unit to service.
5. Camshaft A. Remove the camshaft to inspect the camshaft. B. Inspect the camshaft for large grooves. C. Measure the camshaft to determine if the camshaft is in specifications. Refer to Reuse and Salvage Guidelines for the correct measurements.	Camshaft	Result: The camshaft measured within specifications. Return to service. Result: The camshaft did not measure within specifications. Make the necessary repairs, If the symptom remains, proceed to Test Step 6. If you replace the camshaft, replace the valve lifters. If the problem has been corrected, return the unit to service.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).