Sinister Diesel Anodized Gray Coolant Reservoir Cap 01-16 GM 6.6L Duramax FOX-985-24-103 Key your Duramax crank shaft

Key your Duramax crank shaft in your own driveway with your own tools

Stage 3 System upgrades to 2

Thermometric indicator LED provides operator feedback on motor temperature

Cognito Torsion Bar Keys levels the front with the rear of the truck

These straps offer a fantastic alternative and are made here in the USA

Sinister Diesel Anodized Gray Coolant Reservoir Cap 01-16 GM 6.6L Duramax FOX-985-24-103 Key your Duramax crank shaftDress up your engine in your 6. 6L Duramax with the Sinister Diesel Coolant Reservoir cap. Featuring an anodized gray finish and built from billet aluminum, you can count only great looks and a product that won't crack like the factory cap for years to come. This cap is is made from CNC machined, solid billet T6 6061 aluminum with an interior pressure relief system, so it will continue to function even in case of a gasket failure.