Wehrli 100023 Relief Valve Block Off Kit | 2001-2004 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LB7

Wehrli Relief Valve Block Off Kit – 100023 Fits 2001–2004 GM 2500HD / 3500HD with 6.6L Duramax LB7 Eliminate pressure loss and improve fuel system reliability with the Wehrli 100023 Relief Valve Block Off Kit. Designed for 2001–2004 GM trucks equipped with the 6.6L Duramax LB7, this block-off kit replaces the factory pressure relief valve (PRV) in the fuel rail, sealing the system to maintain consistent rail pressure under heavy load or tuning conditions. This is a must-have upgrade for high-performance Duramax builds, especially when running larger injectors, aggressive tuning, or upgraded CP3 pumps. By removing the factory PRV, you reduce the chance of fuel pressure bleed-off that can lead to reduced power, injector issues, or drivability concerns. Key Features: - Blocks off factory fuel pressure relief valve to prevent pressure loss - Improves fuel rail consistency under load and during tuning - Ideal for tuned or modified Duramax applications - CNC-machined for precise fitment and leak-free seal - Quick and simple installation - Compatible with factory and aftermarket fuel systems - Designed and manufactured by Wehrli Custom Fabrication (WCFab) Fitment: 2001, 2002, 2003, 2004 Chevrolet Silverado 2500HD / 3500HD 2001, 2002, 2003, 2004 GMC Sierra 2500HD / 3500HD With 6.6L Duramax LB7 Warranty: Covered by Wehrli’s limited lifetime warranty. Contact WCFab for full terms and support.