AN -4 LS Steam Port Adapter For Cylinder Head, Black

• T6-6061 CNC-machined aluminum construction
• Black anodized for great appearance and corrosion protection
• Includes high-temperature compatible O-ring seal and zinc plated Allen bolt
• Sold individually (two or four required depending upon application)

Convert Your LS Steam Ports to AN -4 Fittings For Easy Custom Steam Line Creation

We all know that GM’s LS engine is a fantastic way to make easy horsepower in just about any vehicle. Thanks to the ubiquitous LS swap and the huge aftermarket support that it has, you can drop an LS into just about anything in a weekend. However, the LS V8 is still a mass produced engine that has its share of manufacturing complexities, one of which is potential air entrapment within the cooling system. GM placed the thermostat housing in the water pump and lower than the coolant passages in the cylinder heads. This makes getting all the air out of the cooling system difficult. Trapped air can cause steam pockets, overheating, detonation, and tuning issues at a minimum. Total and catastrophic engine failure if you’re not paying attention.

GM engineers added LS steam vents to the cylinder heads (either two at the front or four, one in each corner, depending on model year/application) that were tied together via tubes/hard line and routed to the radiator to assist in purging the air from the cooling system. It works well, but the factory hard lines can rust out, crack, or interfere with aftermarket components like intake manifolds, engine valley plates, and more. Converting the LS steam ports to use flexible coolant lines is a terrific way to ensure your LS stays cool and all your aftermarket bits used in your LS swap play well together. This is why we’ve tooled up these beautiful billet aluminum CNC-machined LS steam port adapters with AN -4 male fittings to use any AN -4 hose and routing of your choice. Each one includes a high-temp sealing O-ring and zinc plated retaining bolt.

Direct Fit LS Steam Port Adapters Provide A Flexible Cooling Solution

Depending on the driveline angle of your LS swap, you may only need two of our AN -4 LS steam port fittings at the front of your engine and then plug the rear steam ports (if equipped) with a pair of steam port block offs. If your LS swap driveline is leveled out, you may need to run additional AN -4 LS steam port fittings at the rear and then connect all four LS steam vent fittings through your choice of AN -4 hose and AN -4 fittings. Push lock or traditional AN hose with black, stainless, and other color fitting options will compliment any LS engine. Connect the front and/or rear LS steam port lines via AN tee fittings or to a manifold of your choice and then feed the coolant lines from your LS steam vent to water pump or to your radiator (radiator is the preferred choice in most cases).

Chevrolet

• LM7, L59 – Avalanche 1500 (2002–2006)
• LMG, LY5, LC9 – Avalanche (2007–2013)
• LS1 – Corvette (1997–2004), Camaro (1998–2002)
• LS6 – Corvette Z06 (2001–2004)
• LS2 – Corvette (2005–2007)
• LS3 – Corvette (2008–2013), Camaro SS (manual, 2010–2015)
• LS7 – Corvette Z06 (2006–2013)
• L99 – Camaro SS (auto, 2010–2015)
• L77 – Caprice (2011–2013)

GMC

• LM7, L33 – Sierra 1500, 1500 Classic (1999–2007)
• L59 – Flex-fuel variant used in 1500 Classic
• LY5, LC9 – Sierra 1500 (2007–2013)
• L83 – Sierra 1500 (2014–2016, Gen V)
• LQ4, LQ9 – Sierra 1500 HD, 2500, 2500 HD, 3500 (2001–2006)
• LY6 – Sierra HD/Classic (2007–2010)
• L96 – Sierra HD (2011–2016)

Cadillac

• LQ9 – Escalade, Escalade EXT, Escalade ESV (2002–2006)
• L92, L94 – Escalade, EXT, ESV (2007–2016)