Page 36 - WHITE BOOK

Research
Ref No FRX 090905 January 19th, 2006 Page Number 2
passageways. Theycauseincreasesinfrictionresultinginhigherenergyrequirementsor malfunctions and increased operating temperatures causing autocatalytic effects on the oils ability to preventsludge. Theyaccelerateacidbuild-uppromotingcorrosion. Thenetresultisanincreasein maintenance and operating costs and shorter component life.
Although there are a variety of qualification tests performed on new fluids to verify the products as acceptable, no industry specifications exist today that allow a user to determine if the in-service fluids are acceptable or should be condemned.
Fluidchangeintervalshavehistoricallybeenbasedontime-in-service. Whenavailablethesetime basedrecommendationsarebetterthannorecommendation. Buttime-in-servicebasedPM (Preventive Maintenance) does not take into account the quality of the fluid being used or the quality ofthemechanicalcomponentanditsoperation. Additionalconsiderationsincludefluidsthatare depleted before their time by intrinsic (chemical and thermal stability) and extrinsic (maintenance & environmental)factorsand/orabnormalevents(includingseveredrivingconditions). Thereforea combination of a condition-based evaluation and time-in-service provides a more complete method for establishing fluid change intervals.
It is well known that many fleet operations utilize laboratory-based testing schemes for fluid evaluation as part of their PM schedules. It has been well documented by many technical papers and it is generally agreed that lubricant breakdown and the resulting sludge shortens equipment life and reduces performance causing an overall increase in operating costs.
It should be noted that in all cases (except brake fluid) a key factor in condemning the fluid is sludge orvarnishformation,orthefluidsinabilitytopreventsludgeduetoadditivedepletion. Inatesting laboratory these conditions are measured by changes in the amount of high molecular weight oxidation resins (sludge) in the fluid, or changes in additives, acidity, viscosity and dispensing properties. Inthefieldtheseconditionsaremanifestedasadarkeningofthefluid. Thiscanbeseen easiestinthebrowncoloranATFchangestowhenitisnolongerserviceable. Alldegraded lubricatingfluidsexhibitthischaracteristicwhentheyarenolongerserviceable. Changesinbrake fluid color is not caused by sludge or varnish formation rather discoloration due to contamination or decompositionof thefluid.
The beneficial consequences of condition-based fluid PM include greater component life and reliabilityandareductioninoverallmaintenanceandoperatingcosts. Furthertheconditioned-based evaluation can detect problems that if otherwise are not detected can cause catastrophic failures. Essentially,condition-basedevaluationactsasanearlywarningdevice. Thereforeaneedexiststo develop and standardize condition based recommendations for fluid PM.
In order to identify the common fluid change recommendations and testing qualifications of the fluids specified above we have reviewed a large number of papers published by standards organizations (such as SAE), independent companies and individuals, OEM recommendations, and
The comments and recommendations rendered are for general advisory purposes only and intended for the sole use of Fluid Rx. Distribution of copyright protected items is limited. These services are offered by Noria without warranty or liability as to accuracy or completeness of this information.
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