Understanding Oil Contaminants

Tom Bock
February 2019

Over the past few months I received some questions I thought you might find interesting:

What physical property levels require the oil to be changed? The general rule is an increase or decrease of one viscosity grade, antifreeze contamination, TBN (Total Base Number) below 2.8, excessive oxidation or nitration, excessive silicon (sand/dirt) in oil. The viscosity increases with higher soot levels, oil overheating and antifreeze intrusion. The viscosity decreases with fuel and water dilution. The oxidation and nitration are usually caused by heat and/or back pressure due to exhaust restriction. The TBN is affected by heat and usage time as well as acid production. The sand and dirt usually enter the engine through air intake leaks or clogged air filters. Keeping oil levels correct will help to reduce heat related issues and a by-pass system will control acid levels, remove solid contaminants and extend useful oil life.

Why does the TBN drop so fast? If new lube TBN is 8.5 why does it drop to half that number after one sample? The Total Base Number (TBN) measures the alkaline content present in the oil. The base consists of alkali – primarily calcium and magnesium that are antacids to neutralize acids as they develop. The calcium and magnesium lose some potency as the encounter the heat of the engine oil. Think of your medication that should be kept cool and dry to be effective. Heat causes reactions that reduce potency causing the drop in TBN. The oil manufacturers place enough base materials to protect the engine from the acidic corrosion. Oil manufacturers recommend the oil be changed when TBN reaches 20% of starting TBN. OPS recommend not dropping TBN below 2.8 to ensure sufficient base is available. The base will last longer if the oil is not overheated and acid was prevented from forming with the use of by-pass filtration systems that reduce levels of condensation water in oil.

Will the filters that have TBN enhancers increase my TBN levels? The oil sample results show increased levels of calcium and magnesium with slightly higher TBN levels. If the filters are cost effective for your operation, I would recommend them.

The oil sample company usually sends me my results via email, but it doesn’t show the history of my last two reports? This happens when the sample is submitted without a component or unit number or the name is changed requiring establishment of a new account. For example, if you typically enter Bob Jones Trucking, then change to BJs Trucking, chances are the data entry person would not match the two and start a new account. If the email address is not entered on the sample form or is illegible, then no email will be sent. Not recording any unit # would show up as unknown and an email would not be sent nor would historical data be included on the report. The general rule is garbage in, equals garbage out.

Is it true that you can go 100,000 miles between oil changes? I must answer this question hundreds of times each month. YES, if you use a by-pass system that removes solid and liquid contaminants. If you stop by OPS Booth 68216 at The Mid-America Truck Show I’m sure there will be someone using the OPS EcoPur system more than willing to share their experience with 100K, 200K and 300K oil change intervals.

Don’t forget to mark your calendar for The Mid-America Truck Show March 28-30 in Louisville KY. You can register for free admission at: https://www.truckingshow.com/registration

If you have any questions or topic recommendations for this column, please email me at: [email protected]