SCREEN AS 4Z8818 - Caterpillar

Depending on application severity and localized environmental conditions, and also depending on maintenance practices, operating Direct Injection (DI) diesel engines and operating PC (Precombustion Chamber) diesel engines on fuel with sulfur levels over 0.1 percent (1000 ppm) may require significantly shortened oil change intervals in order to help maintain adequate wear protection. Refer to this Special Publication, "Fuel Specifications" section, "Diesel Fuel Sulfur" topic for additional information.
Note: Do NOT use only this Special Publication as a basis for determining oil drain intervals.This Special Publication does not address recommended oil drain intervals, but rather provides guidance that should be used with your specific engine/machine Operation and Maintenance Manuals in determining acceptable oil drain intervals. Consult your engine/machine Operation and Maintenance Manuals, and consult your Cat dealer for additional guidance, including but not limited to guidance on establishing optimized and/or acceptable oil drain intervals.Total Base Number (TBN) and Fuel Sulfur Levels for Engines That Use Heavy Fuel Oil (HFO)
Note: Only specially configured 3600 diesel engines can use HFO.The use of Cat S O S Services oil analysis is recommended for determining oil life.TBN is also commonly referred to as Base Number (BN).Generally, lubrication oils for engines that use heavy fuel oil are available with a TBN in a range of 20 to 50 ("ASTM D2896"). Oil companies list these oils that have a high TBN as oils for "trunk piston" or "medium speed marine" diesel engines. Most of the Caterpillar experience is with the oils that have a TBN of 30 or 40. The TBN for a new oil depends on the fuel sulfur level. The TBN for a new oil depends on the fuel sulfur level. For 3600 Series engines that use heavy fuel oil, the minimum new oil TBN must be 20 as determined by the "ASTM D2896" procedure.Engine oils of high TBN can neutralize the sulfur in the fuel and allow for long drain interval. However, oils with a high TBN and/or high ash can produce excessive deposits on the pistons and valves. These deposits can lead to the following results:
A loss of stable oil control
Polishing of the cylinder bore
Guttering of the valvesHigh quality engine oils that are formulated for operation using HFO are balanced to allow the desired oil drain intervals while protecting engines from excessive deposits. The oil must also have the proof of performance that is explained in the Selecting a Commercial Oil article.Use the following guidelines for fuel sulfur levels that exceed 2.0 percent:
Choose an oil with the highest TBN that meets the Caterpillar performance requirements.
Base the oil change interval on the oil analysis. Ensure that the oil analysis includes the condition of the oil, TBN, and a wear metal analysis. Reduce the oil change interval, if necessary.TBN testing is an optional part of the S O S Services oil analysis program. TBN testing may be done in addition to the standard S O S Services tests for oil deterioration. In most applications, the S O S Services tests for oxidation, sulfation, viscosity,