Can an engine oil change be effected by a deteriorating Motor oil base number?

Why would it be of interest to know if an engine oil change can be determined by a deterioration in the Motor oil base number? Well quite simply; with the cost of motor oil (and oil filters) increasing every other month, no one wants to change oil unless it’s necessary.

Why does the deterioration in the motor oil base number indicate an engine oil change is due?

Base number testing, which measures
the reserve alkalinity of the lubricant, is primarily applied to engine crankcase applications. It is the ability to neutralize acids created during the normal combustion process of an internal combustion engine. The base number, which was formerly known as the Total Base Number, can be defined as the quantity of acid, expressed in terms of potassium hydroxide, that is required to neutralize all basic constituents present in 1 gram of sample.

Once the base number reaches 50 percent of the starting value for that lubricant (specifically that batch of lubricant vs. manufacturer spec sheets), a cautionary alarm is generally broken. As the base number decreases over time, you can expect the rate of change to increase.

This cautionary alarm gives you time to prepare for that increased rate of degradation. If the base number (BN) falls to about 50 percent of the value of new oil, it’s a good indication that it’s time for a complete engine oil change.

Is there any way of improving the Base Number and extending the engine oil change?

However, adding about 25% fresh engine lubricant to a 5 lt system, could extend the time to an engine oil change, but this can only be confirmed with oil analysis (Note: This depends on several factors, with the severity of the lubricant being the primary factor; and by way of example, 500ml is unlikely to make a significant difference). This is because you are basically diluting the acids in the sump, with fresh oil. Other parameters on the oil analysis should also be taken into consideration before determining this to be the best route on extending an engine oil change.

Of course, using synthetic oil has the advantage that engine oil change intervals can be more than doubled, under favourable conditions. If you’d like to find out more about Habot synthetic lubricants, please contact us for professional advice.