What is meant by the TBN of oil?
TBN stands for Total Base Number, which is a measure of how well the oil can neutralize acidic combustion by-products. The higher the TBN of new oil is not always a good indicator of how well the TBN will last when the oil is subject to extreme heat and corrosive exhaust gases. (TBN retention) Some oils with high starting TBN’s are used up very quickly leaving little protection against corrosive by-products that form in the used oil towards the end of the drain cycle. CITGARD and SynDurance heavy duty diesel engine oils have proven to offer excellent TBN retention and corrosive wear protection under severe operating conditions and extended service intervals.