Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/431954
coolant line or an exhaust gas recirculation (EGR) system failure. Once the root cause has been determined, an experienced data analyst can make informed recommenda- tions for correcting the problem and assist in establishing fluid maintenance proce- dures for preventing a recurrence. Life-Cycle Management Coolant analysis not only can detect deficient maintenance practices, but it can also assist you in implementing corrective actions to ward off issues within the cooling and lubrication systems, as well as provide indications of shortcomings in equipment operational practices and maintenance procedures. Combining Coolant Analysis and Oil Analysis When reviewing a coolant analysis report, it is important to evaluate it in concert with the oil analysis performed at the same maintenance interval. The effects of engine overheating may be evident in both oil and coolant samples. Remember, cooling system deficiencies affect all systems, including the engine, transmission and hydraulics. Engines High coolant temperatures can cause high oil temperatures, reducing the oil's operating viscosity and thereby its hydrodynamic lubricity. This leads to oil oxidation and eventual engine wear. This could be evident in ring sticking, piston glazing or varnishing, and valve wear, which often masks the fact that a cooling system problem was a contributing factor. Transmissions An overheated cooling system can also shorten transmission life. Transmission disc slippage may occur as a result of reduced oil viscosity at elevated tempera- tures. Transmission slippage creates more heat, which causes oil oxidation, and a vicious cycle is established. Hydraulics Hydraulic pumps and motors become less effi- cient at elevated temperatures and may reduce the life of valves, pump slippers, barrels, plungers and seals due to reduced oil viscosity and oil oxidation. Engines, transmissions and hydraulics are often repaired with no consider- ation given to the possibility that a serious cooling system problem may have precipitated the issue. As a result, the same failures happen again and again. Coolant analysis can dramatically improve machine performance, reduce unnecessary repair and replacement costs, and extend the life of equipment by optimizing the condition of the mechanical systems involved and the fluids that keep them running. About the Author Elizabeth Nelson is the coolant program manager for Analysts Inc. She can be reached at enelson@ analystsinc.com. MAINTENANCE AND RELIABILITY 42 November - December 2014 | www.machinerylubrication.com Understanding a Coolant Analysis Report Corrosion, cavitation, localized overheating, electrolysis and lack of coolant maintenance are just a few of the many destructive conditions that can cause major systems damage. A coolant analysis report should be easy to read with detailed conclusions and maintenance recommendations that will enable you to reduce major repairs and increase equipment uptime, productivity and safety. Unit ID, Manufacturer, Model and Coolant Type are extremely important to a data analyst in determining if the coolant meets engine and coolant OEM specifications and in providing accurate maintenance recommendations. Silicon , Boron, Molybdenum and Phosphorous are inhibitors present in coolants for metal protection and pH control. Inhibitors present are dependent upon the coolant formulation. Nitrite is present in heavy duty, fully formulated conventional coolants, nitrite OAT and hybrid coolant formulations. Some are a combination of nitrite and molybdenum. The maximum acceptable level of nitrite or nitrite and molybdenum combined is 3200 ppm (parts per million). Excessive nitrite levels can lead to solder corrosion. Reserve Alkalinity indicates a coolant's capacity to neutralize acids formed in (glycol oxidation products) or entering (exhaust gas blow-by) the cooling system. The rate at which reserve alkalinity decreases, along with the amount of inhibitor added, will help predict when the coolant will become too acidic to protect the cooling system from corrosion. An adequate pH range should remain between 8.0 – 11. 0 for conventional coolants and 7. 0 – 9.5 for ELCs. Proper pH levels are necessary for optimum corrosion inhibitor performance. Adequate glycol levels must be maintained to ensure proper Freeze and Boil Point protection. High glycol can cause additive dropout and decrease coolant life. A glycol range of 45% to 60% is recommended. Calcium and Magnesium Contaminants present in an engine coolant will form scale on hot metal surfaces. Scale is an efficient insulator and can cause localized engine overheating which can result in component failure. OEM and ASTM specifications are set on Total Hardness levels as CaCO. Corrosion occurs when bu•ers are no longer able to counter acid formation due to thermal degradation. Typical Corrosion Product Sources: Iron — liner, water pump, cylinder block/head Aluminum — radiator tanks , coolant elbows , piping, spacer plates, thermostat housings Copper— radiator, oil cooler, aftercooler, heater core Lead — radiator solder, oil cooler, aftercooler, heater core Data analysts provide you with Maintenance Recommendations based on in-depth analysis, taking the guesswork out of interpreting coolant analysis results. Complete and accurate Sample Information – number of hours on both unit and coolants and filter and fluid change information – is critical for a data analyst to make a proper maintenance recommendation. Referencing the Lab Number will expedite resolving any question when contacting the lab concerning a sample. A coolant analysis report should be easy to read with detailed recommendations that will enable you to reduce major repairs and increase equipment uptime, productivity and safety. Visit MachineryLubrication.com for a full-sized view.