Coolant Bypass Kits for LS Swaps & Engine Builds

Coolant Bypass Kits for LS Swaps & Engine Builds

Coolant bypass kits are commonly used in LS engine swaps and engine compartment rerouting projects to eliminate factory heater core connections, simplify coolant routing, or cap off coolant ports no longer needed after a swap into a non-GM chassis. These kits prevent air pockets and coolant leaks that would otherwise occur when heater core lines are left open or improperly capped.

Popular Upgrades

LS engine coolant bypass kits that cap the heater core fittings on the driver-side intake manifold are the most frequently purchased option for LS swaps in vehicles without a compatible heater core connection. Full coolant reroute kits for the LS1 through LS6 engines simplify the intake manifold coolant circuit by eliminating the throttle body coolant crossover, which reduces coolant routing complexity in a swap. Billet aluminum bypass fitting kits provide a finished, corrosion-free solution compared to rubber-capped fittings.

Why do LS swaps need a coolant bypass kit?

LS engines have multiple coolant ports on the intake manifold that were connected to heater cores, throttle body warmers, and other factory coolant circuits in the original GM application. When the engine is swapped into a different chassis, these ports are often unnecessary and must be properly bypassed or capped to maintain system pressure and prevent air locks in the cooling circuit. A dedicated bypass kit provides the correct fittings, hoses, and hardware to do this cleanly.

Can I use a coolant bypass kit on any LS generation?

LS bypass kits are generation and intake manifold specific. The LS1, LS2, and LS6 use similar intake manifold coolant port configurations, while the LS3 and LS7 use different port layouts. Always confirm the specific engine generation and intake manifold variant when selecting a bypass kit to ensure the fittings match the manifold port threads and hose routing matches your engine bay layout.

Find LS swap components at Black Ops Auto Works. Browse our exhaust systems, air intake systems, and suspension upgrades for your build.