{"product_id":"performance-oil-pump-timing-chain-water-pump-kit-for-chevrolet-silverado-1500-1999-2004-4-8l-5-3l-6-0l","title":"Performance Oil Pump Timing Chain \u0026 Water Pump Kit for Chevrolet Silverado 1500 (1999-2004) 4.8L 5.3L 6.0L","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eHigh-Durability Engine Timing, Lubrication \u0026amp; Cooling Refresh Kit for 1999-2004 Chevrolet Silverado 1500 (GMT800)\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The Performance Oil Pump Timing Chain \u0026amp; Water Pump Kit restores critical lubrication, cam synchronization, and thermal cooling efficiency on the 1999-2004 Chevrolet Silverado 1500 to prevent valvetrain failure and engine overheating.\u003c\/p\u003e\n\u003ch3\u003eThe Stock Chevrolet Silverado 1500 Oil Pressure Loss and Timing Deflection\u003c\/h3\u003e\n\u003cp\u003eFactory \u003cstrong\u003eGMT800\u003c\/strong\u003e trucks powered by the \u003cstrong\u003eGen III Vortec\u003c\/strong\u003e V8 platform frequently suffer from worn oil pump pressure relief valves that stick open, inducing severe low-pressure warnings at idle. Concurrently, high-mileage OEM timing chains stretch, creating camshaft timing retard and ignition jitter that sap low-end torque. Coupled with factory mechanical water pump bearing wash-out and weeping shaft seals, these simultaneous wear items leave the engine vulnerable to catastrophic valvetrain and bottom-end wear under heavy load.\u003c\/p\u003e\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eThis front-dress refresh package eliminates factory failure points in a single service. The high-output gerotor oil pump provides consistent volumetric flow throughout the rev range via an engineered pressure relief mechanism. The matched timing set features hardened alloy sprockets and a pre-stretched chain to maintain tight cam-to-crank indexing. A high-efficiency cast-aluminum water pump delivers balanced coolant flow through the block, sealed by precision timing cover and water pump gaskets that resist thermal expansion fatigue.\u003c\/p\u003e\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 Oil Pump\u003c\/li\u003e\n\u003cli\u003e1 Timing Chain Kit (Chain and Sprockets)\u003c\/li\u003e\n\u003cli\u003e1 Timing Cover Gasket Set\u003c\/li\u003e\n\u003cli\u003e1 Water Pump\u003c\/li\u003e\n\u003cli\u003eAssorted Seals and O-Rings\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cdiv style=\"overflow-x: auto; margin-bottom: 20px;\"\u003e\n\u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; min-width: 300px;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding: 10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eFitment\u003c\/th\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #e0e0e0;\"\u003e1999-2004 Chevrolet Silverado 1500\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding: 10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eEngine \/ Chassis\u003c\/th\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #e0e0e0;\"\u003e4.8L (LR4), 5.3L (LM7\/L59), 6.0L (LQ4\/LQ9) Vortec \/ GMT800\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding: 10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eStock Output\u003c\/th\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #e0e0e0;\"\u003e255-345 hp \/ 285-380 lb-ft\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding: 10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eReplaces OEM Part #\u003c\/th\u003e\n\u003ctd style=\"padding: 10px; border: 1px solid #e0e0e0;\"\u003e\n\u003cdiv class=\"ux-layout-section-evo__col\"\u003e\n\u003cdiv class=\"ux-labels-values__values-content\"\u003e\n\u003cdiv\u003e\u003cspan class=\"ux-textspans\"\u003e12556582, 12586665, 12639249, 12703898, 89060436\u003c\/span\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1999-2004 Chevrolet Silverado 1500 4.8L Vortec V8 (LR4)\u003c\/li\u003e\n\u003cli\u003e1999-2004 Chevrolet Silverado 1500 5.3L Vortec V8 (LM7, L59)\u003c\/li\u003e\n\u003cli\u003e1999-2004 Chevrolet Silverado 1500 6.0L Vortec V8 (LQ4, LQ9)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\n\u003ch4\u003eDoes this fit the GMT800 Silverado 1500?\u003c\/h4\u003e\n\u003cp\u003eYes, this is a direct fit for the 1999-2004 Chevrolet Silverado 1500 equipped with the \u003cstrong\u003e4.8L LR4\u003c\/strong\u003e, \u003cstrong\u003e5.3L LM7\/L59\u003c\/strong\u003e, or \u003cstrong\u003e6.0L LQ4\/LQ9\u003c\/strong\u003e Gen III Vortec V8 engines.\u003c\/p\u003e\n\u003ch4\u003eIs it required to replace the pickup tube O-ring during installation?\u003c\/h4\u003e\n\u003cp\u003eYes, using the supplied correct-spec oil pickup tube O-ring and ensuring a flush seat is mandatory to prevent aeration and loss of oil prime.\u003c\/p\u003e\n\u003ch3\u003eThe Chevrolet Silverado Heavy-Duty Caliber\u003c\/h3\u003e\n\u003cp\u003eBuilt to handle rigorous towing and extreme thermal duty cycles, these upgraded components provide the mechanical longevity and pressure stability demanded by work-ready trucks.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":67545418727672,"sku":"DS-EEMGQYZTJ","price":194.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/performance-oil-pump-timing-chain-water-pump-kit-for-chevrolet-silverado-1500-1999-2004-4-8l-5-3l-6-0l-1.jpg?v=1790723510","url":"https:\/\/performancechiptuning.com\/products\/performance-oil-pump-timing-chain-water-pump-kit-for-chevrolet-silverado-1500-1999-2004-4-8l-5-3l-6-0l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}