Vibration Complaints Caterpillar

Vibration Complaints

Usage:

ENGINES3406, 3406B, 3406C, 3406E TRUCK ENGINES

Problem:

Vibration complaints are usually difficult to describe; have many possible root causes; and are sometimes difficult to resolve.

Solution:

The following is a suggested troubleshooting procedure for resolving vibration complaints:

Vibration Complaints Troubleshooting Procedure

1.Define the problem, both through personal observations and a thorough interview with the customer. Ask questions such as:

*What RPM and/or vehicle speed does the vibration start and stop?

*What are the road conditions when the vibration occurs?

*Has it occurred since the vehicle was new, or did it start after a repair?

*Has the engine's performance changed?

*Where and how is the vibration felt? For instance, is it in the mirrors, steering wheel, pedals, floor, seat, or exhaust. Is it heard rather than felt?

The key is to understand the specifics of the vibration (where the customer senses it). This will pin-point locations which may be further analyzed by using a vibration analyzer, if necessary. Remember, load does not change vibration motion caused by unbalance.

2. Next, look for:

*high oil level,

*loose mounts (engine and cab),

*pulleys out of round,

*binding in all mounts,

*loose brackets,

*broken parts, etc.

*Also check to ensure that fasteners are tight and components are properly aligned.

Repair or replace parts as indicated by this inspection. If the discovery and correction of a problem does not resolve the complaint, go to Step 3.

3.If nothing was discovered in Steps 1 and 2, complete a vibration analysis, using either a IRD 320 Vibration Meter or the Caterpillar 4C-3030 Vibration Analyzer Group. Service technicians must be familiar with vibration analysis and should have completed the Caterpillar Vibration Analyzer Course. Proper troubleshooting procedures and measuring equipment are essential in diagnosing vibration complaints. If you do not have the proper tools or qualified operators, call Caterpillar 3400 Engines Dealer Support Line, Phone (309) 578-2434 for consultation.

4.Remember there can be many contributing factors to truck vibration. Some of these factors may not require parts replacement. Before making changes it is a good idea to have a vibration analysis. This provides a base line (starting point), so the effects of changes/repairs can be measured and compared to the base line.

5.Make changes/repairs based on the results of the vibration analysis.

6.Do NOT rely on personal judgment to validate the success of a change or repair. Retake all vibration measurements to verify the repair was successful.