1999 GMC Sierra 1500 Pickup Owner's Manual - Page 400

Scheduled Maintenance Services 13. EGRSYSTEM INSPECTION* -ConductEGRSYSTEMCHECKas described in theServiceManual. 14. ELECTRONICVACUUMREGULATORVALVE(EVRV) INSPECTION* -Inspect filterforexcessivecontaminationorplugging. If required,clean dry and elementwithasolution of biodegradablesoapandwater,let reinstallelement. 15. ENGINETIMINGCHECKANDDISTRIBUTORCHECK(SOME MODELS)" -Adjust timing to underhoodlabelspecifications.Inspectthe insideandoutside of thedistributorcapandrotorforcracks,carbon trackingandcorrosion.Clean orreplaceasneeded. 16. FUELTANK,CAPAND LINESINSPECTION* -Inspect the fuel tank, capandlinesfordamageorleaks.Removefuelcap,inspectgasketfor anevenfillerneckimprint,andanydamage.Replacepartsasneeded. 17. THERMOSTATICALLYCONTROLLEDAIRCLEANERINSPECTION* A-(If so equipped.)Inspectallhosesandductsforproperhookup. Makesurevalveworksproperly. 18. ENGINEACCESSORYDRIVEBELT(S)INSPECTION* Lookforcracks,fraying,wear, needed. --Inspect belts. andpropertension.Adjustorreplaceas all 19. EVAPORATIVECONTROLSYSTEM(ECS)INSPECTION* -Check fuelandvaporlinesandhosesforproperhookup,routing,andcondition. if equipped.Replaceas Checkthatthepurgevalveworksproperly, needed. 20. SHIELDSANDUNDERHOODINSULATIONINSPECTION Am-Inspect shieldsandunderhoodinsulationfordamageorlooseness.Adjustor replaceasrequired. 21. AIRINTAKESYSTEM INSPECTlONAWCheck theairintakesystem installation to see thatgasketsareseatedproperlyandallhose connections,fasteners,andothercomponents are tight. Alsocheck to be surethattheaircleanerhousingisproperlyseated,thatthecoverfits tightly,andthewingnutsaretight.Tightenconnectionsandfastenersor replacedamagedpartsasrequired. 22. THERMOSTATICALLYCONTROLLEDENGINECOOLINGFAN so equipped.)Withtheengine off andbelow INSPECTI0NA.-(If normaloperatingtemperature,check to seethatthefancanberotated by hand on fluid couplingorviscousdrives.Replaceasnecessary. *An EmissionControlService AAlso aNoiseEmissionControlService .Applicableonly tovehicles sold in theUnitedStates 7-20