Case Study

On-Highway Truck Engine Issues

Affected Component: Engine
Industry Sector: Highway Haulage
Machine: Kenworth T909 Tri-drive highway super quad
Critical Report: Soot, iron and PQ index high, at 14,985 hours


As part of their scheduled maintenance planning, the customer took oil samples of all components using a KOWA-OILCM sample kit to monitor the operation of the truck which was then sent to the Komatsu CMS laboratory for testing.

During the evaluation process, the Komatsu CMS team detected elevated soot levels. This indicated a performance issue with this engine's operation which required further investigation. Had this not been detected, the engine would have continued to wear to the point it would be deemed as "critical" which may could have resulted in unplanned downtime. The results of the oil sample was communicated to the customer which highlighted the critical areas that need their urgent attention and action. To ensure action was taken in a timely manner, the customer was contacted by phone and received direct support and guidance.


After seeing a trend for elevated soot results tested indicated via the FTIR (Fourier Transfer Infrared Spectrometry), we could also see Fe (iron) levels had increased, as well as the Particle Quantifier (PQ) index.

We called the customer to inform him of these results. He was very keen to get it looked a; during phone discussions, we looked at possible scenarios, including the fact that the machine was running hotter than expected. After a further call to the customer to follow up, it was determined that the was due to poor engine condition, with the EGR (exhaust gas recirculation) valve not functioning properly, causing restrictions to the intake.

A new EGR and water pump were fitted to this truck and it was returned to service; a recent sample has returned to a normal evaluation level.