Diagnostic Prior to Overhaul Saved ~$52,000 by Optimizing the Scope of One Overhaul


Diagnostic Prior to Overhaul Saved ~$52,000 by Optimizing the Scope of One Overhaul


With condition monitoring, the crew can detect potential problems early and take proactive measures to fix them, reducing the risk of unplanned downtime, improving safety, and saving on maintenance costs.

Industry Segment

Oil & Gas

Arm Solution

Engine Health Diagnostics through torsional vibration solution


3516B Caterpillar diesel engines


  • A Caterpillar 3516B engine was due for the 2nd Top End Overhaul as per the OEM recommendation
    based on the running hours, but the rig owner had a budget constraint


  • Neptunus has been a preferred partner to this customer for engine maintenance across their multiple rigs
  • Neptunus’ expert advised for pre-overhaul diagnostics using torsional vibration analysis. The objective was to optimize the spare parts list, consumables, manpower and  downtime of overhaul
  • Neptunus’ team went onboard & carried out the engine health inspection through torsional vibration tool
  • The report data showed issues with the fuel injection quality and the crankshaft main bearings. Other health parameters were within acceptable limits. Based on this data, Neptunus recommended only a Top End Overhaul instead of a 2nd Top End Overhaul
  • The diagnostic findings were reaffirmed when the engine was dismantled for a Top End Overhaul. The hatch
    marks on the liner & cylinder bore dimensions were observed to be in limits as per the OEM recommendation.
  • Engine has been running smoothly for over 6000 hours after the Top End Overhaul


  • Direct savings of ~USD 52,000 due to lesser cost of overhaul. This increased the profitability of the rig.
  • We saved 4 days due to the reduced scope (8 days vs 12 days) thus expediting the rig repair project.
  • It allowed the rig and technical teams to focus on the core drilling operations rather than worry about the uncertainty of engine reliability.