Earl's Performance LS Steam Tube Kit

The Earl's Performance LS Steam Tube Kit is a purpose-engineered solution to one of the most critical and commonly overlooked challenges in GM LS engine cooling: trapped air and steam pockets. Because the LS thermostat is positioned in the water pump housing at a lower point than much of the engine's coolant passages, air that enters the system can become trapped — forming bubbles that disrupt coolant flow and create dangerous hot spots. Earl's steam tube kits provide a direct, professional-grade solution to properly vent steam from the cylinder heads and maintain optimal cooling system performance.

Key Features:

• Eliminates Trapped Air and Steam: Engineered specifically for GM LS engines to vent trapped air and steam from the cylinder heads, preventing hot spots and overheating that can lead to costly engine damage
• Multiple Configuration Options: Available in front-vent (two-port) and four-corner configurations to suit a variety of LS swap orientations and cooling system setups
• Choice of Hose and Tubing Styles: Kits are offered with braided stainless steel Speed-Flex hose, black push-on hose, or stainless steel hard-line tubing — each designed to match your build style and performance requirements
• Adjustable, Low-Profile Pivoting Adapters: Includes pivoting steam vent adapters that offer superior adjustability and clearance over factory units, accommodating aftermarket intakes, throttle bodies, and accessories that OEM hard lines cannot route around
• Premium AN-Style Fittings: Features high-quality hose ends and AN-style fittings for secure, leak-free connections and a clean, race-quality appearance in the engine bay
• Complete Kits: Each kit includes all necessary adapters, hose or tubing, and hose ends for a straightforward, professional installation
• Emissions Compliant: Legal for use on emissions-controlled vehicles, as these kits do not affect vehicle emissions systems

Installation Notes:

• Front-vent (two-port) kits connect to the front steam outlets on the cylinder heads only; two GM OEM steam tube block-off plugs (GM #12602540) are required for the rear cylinder head outlets and are sold separately
• Depending on the specific cooling system configuration, modifications to the radiator or water pump outlet hose attachment point may be required

Earl's Performance, a brand under the Holley Performance Products family, has been a trusted name in high-performance AN plumbing for decades. These LS Steam Tube Kits deliver the same precision engineering and durable materials that professional engine builders and racers depend on — making them an essential upgrade for any serious LS swap or performance build.