Wrong Oil Use

A small mixed van fleet began experiencing increased oil consumption and warning light issues across several vehicles. The problems appeared gradually and were initially treated as unrelated faults.

Further investigation showed the issue was linked to engine oil selection during routine servicing.

How it happened

The fleet used several vehicles with similar engine sizes but different manufacturer requirements. During servicing, the same engine oil was used across all vans to simplify stock and reduce cost.

While the oil viscosity appeared suitable, it did not meet the specific approvals required by some of the engines.

Identifying the impact

Vehicles using the incorrect oil began showing higher oil consumption and emissions related warnings. In some cases, diesel particulate filter regeneration frequency increased.

Although no immediate failures occurred, long term engine and emissions system damage became a concern.

Correcting the oil choice

Vehicle manufacturer specifications were reviewed for each model. The fleet switched to engine oils that met the required approvals, even where viscosity grades appeared identical.

Oil storage and labelling were improved to prevent incorrect oil use during future servicing.

The outcome

Oil consumption returned to normal levels, warning lights reduced, and engine behaviour stabilised.

The fleet accepted slightly higher oil costs in exchange for improved reliability and reduced risk of long term damage.

Key takeaway

Using the wrong engine oil does not always cause immediate failure, but it can quietly create serious problems. Matching oil approvals to vehicle requirements is essential, even when oils appear similar.