The build-up in acidity can be a problem in certain lubricants (mainly crankcase and engine applications due to combustion products blow by). For this application lubricants with an additive package, which provides reserve alkalinity to neutralise acids generated during combustion, are used. It is important to monitor how much of this additive package is left by checking the alkalinity of the oil – once this is depleted the oil can become very corrosive.
A rapid decrease in the Base Number may be due to the possible following reasons:
- Abnormal fuel dilution
- Using high sulphur fuel
- Poor combustion
- Excessive blow by
- Severe oxidation
- Soot contamination
- Too long a drain interval
- Wrong top-up oil
- Glycol dilution