Silent block diesel engine’s premature ageing

Problem
Vibrations from a diesel engine located on the vehicle’s roof were transmitted to the car body shell (passenger compartment).
Aim
To determine the root cause of the problem. A test was designed to determine whether the transmission was due to an increase in vibrations within the engine or premature ageing of the engine’s suspension (two stage suspension).
Instrumentation/ measurement
Vibrations were measured in different stages of the suspension in the cars where faults/problems had been detected.
Results
After studying the frequency response function (FRF) at different points of the suspension, CETEST determined that the root problem was premature ageing of one of the suspension stages on certain silent blocks.
Actions
The silent blocks were inspected and only those identified as potentially faulty were replaced, thus reducing repair costs.
Case Study: Silent block diesel engine’s premature ageing