Heater Core Bypass Hose Thickened EPDM for Chevy LS1 LS2 LS3 LSX LQ4

Upgrade your LS engine’s cooling performance with a thickened EPDM heater core bypass hose engineered for direct OEM replacement and long-term thermal stability.

Main Description

This precision-molded coolant crossover loop connects directly to the water pump, routing fluid efficiently through the heater core supply and return channels. Factory rubber tubes frequently harden or swell under repeated heat cycles, restricting cabin warmth and trapping air pockets in the cooling circuit. This reinforced replacement restores consistent coolant circulation while maintaining precise engine operating temperatures. Constructed from heavy-duty EPDM rubber, it resists degradation from hot antifreeze, oil mist, and fuel vapors without losing elasticity. The tapered internal diameter bridges 5/8-inch and 3/4-inch ports, delivering a secure, leak-resistant seal across GM LS and LT platform builds.

Benefits & Tips

• Wipe mating water pump surfaces clean of old silicone or corrosion before installation to ensure the rubber grips evenly across the entire circumference.
• Apply a thin layer of high-temperature silicone grease to the hose barb areas during fitting to reduce friction and protect against future clamp galling.
• Bleed the air lock thoroughly after refilling with fresh glycol-based coolant to eliminate overheating spikes during initial drive cycles.

Product Specifications

• Material: Thickened EPDM Rubber
• Horse End IDs: Tapered 5/8-inch to 3/4-inch
• Design: U-shaped coolant crossover bypass
• Compatibility: GM Chevrolet & Pontiac LS/LT Series (Gen 3, 4, 5)
• Engine Models: LS1, LS2, LS3, LSX, LQ4, LT variants (1998 onward)
• Chemical Resistance: Coolant, oil, and fuel stable
• Origin: Mainland China

Package Includes

• 1 x U-shaped Heater Core Bypass Hose
• 2 x Stainless Steel Clamp Sets

Warnings & Reminders

Confirm your water pump features dual ports measuring exactly 5/8-inch and 3/4-inch before purchase. This component serves exclusively as a plumbing bridge and does not replace the factory bypass tube casting. Always pressurize and test the entire cooling loop after assembly to verify zero leakage prior to regular operation.

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