After the oil and filter change on a diesel engine, the oil warning light remains on. Who is correct in diagnosing the issue, Technician A or Technician B?

In diagnosing the issue of the oil warning light remaining on after an oil and filter change, Technician A is correct if they identify that the problem could be related to oil pressure rather than just a malfunctioning sensor or a simple oversight.

After an oil change, the engine may take some time to build up oil pressure, especially if there was a significant amount of oil drained. If the oil filter was not filled prior to installation, there may be an initial delay in oil reaching the sensor, which keeps the warning light illuminated. Additionally, if the new oil is significantly different in viscosity or type from the previous oil, it could also affect pressure readings.

Furthermore, if there was any air trapped in the oil system during the change, this could also cause a temporary drop in oil pressure, leading to the warning light staying on. A systematic approach to troubleshooting would involve checking oil levels, examining the oil pressure sending unit, and verifying that the oil system is free of air.

Technician B might suggest a different issue entirely or dismiss the oil pressure as a cause, which might overlook the fundamental connection between oil pressure and the warning light. This underlines the importance of understanding the nuances of engine operation and the effects of maintenance on these systems.