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The Sinister Diesel coolant reservoir (degas) cap is a billet T6-6061 aluminum replacement for 2001–2016 GM Duramax 6.6L coolant reservoirs. CNC-machined with an interior pressure relief system, the cap functions like the factory part but resists failure-prone factory designs. Rated to 15 PSI and anodized in Sinister Gray, it includes the Sinister Diesel logo and installs as a direct replacement on compatible Duramax reservoirs.
Sinister Diesel 01-16 GM Duramax 6.6L Coolant Reservoir (Degas) Cap - Gray
