|Christian P. Koop|
The fluid many of us refer to as the life blood of the engine or motor continues to evolve rapidly to meet ever-changing engine manufacturer requirements.
Many of these changes have been necessary because of technological improvements; however, many of the formulation changes in oil were developed mainly because of the ever-tightening emission regulations by the Environmental Protection Agency (EPA). These were for cars and light trucks first and later medium and heavy trucks. I fondly remember that when I was a young mechanic apprentice (technician in today’s lingo) working in a garage that selecting the correct oil for the engine I was working on was very simple. Not so anymore, and if you don’t use the correct type for your emergency response vehicle (ERV) engine – whether gas or diesel – you could decrease fuel economy and, in worst-case scenarios, even cause serious damage. Failure to use the correct motor oil could not only lead to premature hard part damage but also compromise auxiliary systems like fuel, catalytic converters, and diesel particulate filters (DPFs). If damage occurs during the engine warranty period, the manufacturer could void the warranty.
Although most engine manufacturers would like you to use the oil they market, you don’t have to as long as the oil you use meets the engine manufacturer’s specification requirements. This is where it can get complicated. Previously in the United States, we relied solely on the American Petroleum Institute (API) rating to determine the correct oil for an engine. There are other agencies that have come about because of increased demand for ensuring the correct oil is being used in modern engines. These are the International Lubricant Standardization and Approval Committee (ISLAC) specification for domestic and Asian vehicles and the European Automobile Manufacturer’s Association (ACEA) specification for European OEMs. Ironically, with the increasing number of rating agencies, the manufacturers still felt it necessary to develop their own motor oils.
Here is what typically happens: An engine manufacturer designd an engine to meet either an emissions or a performance standard. When it fails to meet that threshold with industry-standard lubricants, all bets are off, and if it takes a different oil to do so, so be it! A few may remember back in 2011 when General Motors (GM) came out with its own oil specification named dexos1 for gasoline engines and dexos2 for diesels. Dexos motor oil is a synthetic, and in the quest for improved fuel economy many manufacturers have been switching from conventional to synthetic because it has been proven to reduce friction and increase fuel economy. In the owner’s manuals, GM warned that failure to use oil that did not meet its specs would void the warranty if a failure was attributed to lubrication. More recently, Ford Motor Company rejected the latest diesel oil spec: CK-4 (API rating), which replaces the CJ-4 spec that had been in place since 2006. Ford has now formulated its own oil for use in its diesels, stating that the old spec was causing excessive abrasive wear.
More than Lubrication
Keep in mind that oil has a tough job to perform in a modern engine because it has to seal, cool, clean, and protect in addition to its basic lubrication requirements. Modern oil comprises many chemical additives to help it do its job in today’s engines. Some of the major areas for which motor oil provides protection follow:
- Abrasive Wear: This wear occurs when contaminants such as dirt, soot, silica, and other particles suspended and carried by the oil get in between two metals inside the engine and cause wear.
- Bore Polish: If the cylinder liner gets excessively polished, the rings will lose their ability to properly seal against the forces of combustion, which causes low power and oil burning.
- Piston Deposits: Buildup of carbon deposits in between the piston rings and lands can cause the rings to bind and not provide enough tension to properly seal the cylinder bore. This will cause loss of power and excessive oil consumption and is common in engines that are allowed to idle for prolonged periods of time. It commonly happens to ERVs because of idle time at accident and fire scenes. Diesels have a tendency to cool down at idle, and excessive idle time is one of the worst things you can do to them.
- Soot Thickening: As diesel fuel burns, soot is created and forced into the oil. When the oil holds too much soot, it thickens and will rob the engine of fuel economy and power and, depending on the engine, will affect fuel injection.
- Oxidation Thickening: When the oil gets sheared and oxygen molecules are mixed with the oil, the oil will thicken. This also affects fuel economy and power and causes even more engine wear during cold starts because of the increased time the oil takes to reach critical areas that need immediate lubrication at startup.
- Shear Stability: This measures the amount of viscosity an oil loses during operation and is the ability of the oil to resist shearing or cutting at the molecular level. Oil shearing occurs in places like the oil pump, camshaft, piston rings, and other areas where oil is squeezed out from between two surfaces momentarily. When this happens to oil, the molecules usually are not able to come back together, and viscosity is lost as they become trash in the oil. Additives known as “viscosity index improvers” help oil retain its viscosity, particularly in multiviscosity oils. Full synthetic oils are superior in this area and do not need as much additive compared to conventional oil. Some engines cause more oil shearing than others because of design, particularly with engines that use high-pressure engine oil to operate fuel injectors.
- Emissions Compatibility: The oil additives must be compatible with the emissions components. If not, depending on the engine type, catalytic converters, selective catalyst reduction (SCR), and the DPF can be poisoned and ruined. With some of these systems costing $10,000 or more, you want to make sure you are using the correct oil.
- Corrosion: When an engine operates, the air it pulls in from the intake contains moisture (water). Some of this moisture goes out the tailpipe as steam, but some remains inside the engine where it can lead to corrosion.
It is very important to stay on top of the latest oil requirements because failing to use the correct oil in your ERV fleet could void the warranties if oil-related failure occurs during the warranty period. With today’s tighter maintenance budgets and the need to save dollars wherever possible, spending more money on the correct oil could lead not only to savings in reduced downtime for engine repairs but also increased fuel economy.
Oil is no different than coolant or transmission fluid with the following two exceptions: It is changed more frequently and, with regard to coolant, the manufacturer is unable to change the color of the oil. This is the greatest concern for owners: Servicing personnel may be casual about servicing engines knowing that it would be virtually impossible to detect whether or not they put the correct oil in.
CHRISTIAN P. KOOP retired as the fleet manager for the Miami-Dade (FL) Fire Department after 35 years with Miami-Dade County and four years in the military. He has been involved in the repair and maintenance of autos, military track and wheeled vehicles, heavy equipment, and emergency response vehicles for the past 40 years. He is a member of the Fire Apparatus & Emergency Equipment Editorial Advisory Board. He has an associate degree from Central Texas College and a bachelor’s degree in public administration from Barry University and has taken course work in basic and digital electronics. He is an ASE-certified master auto/medium/heavy truck technician and master EVT apparatus and ambulance technician. He is a member of the board of directors of EVTCC and FAEVT and a technical committee member for NFPA 1071, Standard for the Emergency Vehicle Technician Professional Qualifications.