Best 3/4 90 Degree Heater Hose Options for LS Swap and Universal Fit

Choosing the right 3/4″ 90-degree heater hose matters for routing, temperature tolerance, and leak-free connections. The picks below include molded LS swap hoses, silicone elbows, and a universal OEM-style heater hose to cover common swap and replacement needs.

Product	Type	Key Feature
BLACKHORSE-RACING LS Swap Heater Hose Set	Molded 90° Heater Hose Set	LS-specific clearance routing
zslssports Swap Heater Hose 90° Bend	Molded 90° Hose + Clamps	LS engine compatibility (LS1/LSX/LQ4/LQ9)
AC PERFORMANCE 3/4″ 90° Elbow Coupler	Pure Silicone 90° Elbow	High-temp silicone, reinforced
Gates 28480 HVAC Heater Hose – 90°	OEM-style Heater Hose	Resists ECD and water permeation
X AUTOHAUX 19mm 90° Silicone Elbow	Silicone Elbow With Clamps	Universal, high temperature range

LS Swap Heater Hose Set 90 Degree Molded Heater Hose

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Brand: BLACKHORSE-RACING

Features: Size: 5/8″ ID & 3/4″ ID, 4″ x 24″ length segments. Type: 90 Degree molded hose. The design is targeted at LS engines with limited passenger-side clearance.

This molded set is engineered to address interference issues from factory heater outlets on LS water pumps. The molded 90° bend reduces the need for extra fittings and long runs when routing near control arms or inner fenders. Because the product includes specific ID sizes, it can be matched to factory heater ports or aftermarket adapters.

Swap Heater Hose 90 Degree Bend + 2 Clamps 3/4″ ID

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Brand: zslssports

Features: Molded 90° hose with included clamps. Designed for LS series engines including LS1, LSX, LS2, LS3, LQ4, and LQ9. Stated suitability for passenger-side tight clearance areas.

This hose set is similar to other LS-specific molded hoses and emphasizes fitment across multiple LS variants. The included clamps make installation straightforward for retrofit or replacement. Because it’s molded for tight spaces, it reduces the likelihood of kinks or hard bends that could restrict coolant flow.

AC PERFORMANCE ID 3/4″ 90 Degree Elbow Coupler Silicone

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Brand: AC PERFORMANCE

Features: 90 Degree elbow coupler, ID 3/4″ (19mm), leg length 3.5″ (90mm). Constructed of high-temp reinforced pure silicone. Temperature resistance from -76°F to 482°F (-40°C to 250°C). Rated to 80 PSI maximum.

As a reinforced silicone elbow, this component is useful where higher temperature tolerance and flexibility are desired. The pure silicone construction provides improved resistance to heat and aging vs some rubber hoses, and the stated pressure rating supports typical coolant system pressures. This part functions as a slip-on elbow that pairs with hose clamps or barb fittings.

Gates 28480 HVAC Heater Hose – 90-Degree Angle

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Brand: Gates

Features: 90-degree angle heater hose, 52″ centerline length, .75″/19mm I.D. Engineered to resist electrochemical degradation and water permeation. Can be used with heater hose connectors and bulk hose to create custom assemblies. Suitable for coolant, air, and water applications.

This OEM-style Gates hose is built for durability and compatibility with factory-style heater connectors. Its resistance to electrochemical degradation helps when different metals exist in the cooling system, and low water permeation reduces coolant loss over time. It’s suitable for custom assemblies when paired with appropriate fittings.

X AUTOHAUX 19mm 0.75″ ID 90 Degree Elbow Silicone Hose

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Brand: X AUTOHAUX

Features: 19mm (0.75″) ID 90° elbow, length 90mm (3.54″). Working temperature range -60°C to 300°C. Supplied with 2 clamps. Marketed as a universal engine silicone elbow suitable for intercooler or intake piping applications.

This universal silicone elbow offers a wide temperature operating window and includes clamps for installation. Although marketed for intake and intercooler piping, the silicone construction and ID make it compatible with heater circuit applications where silicone elbows are acceptable. Check clamp type and mating surface before installing in a coolant circuit.

Buying Guide: How To Choose A 3/4″ 90° Heater Hose

Selecting the correct heater hose requires balancing fitment, materials, temperature resistance, and system compatibility. The points below cover the most important factors for swaps, replacements, and custom routing.

1. Fitment And Inner Diameter

Match the ID: A 3/4″ (19mm) ID is common for many heater outlets and fittings. Confirm engine port size and barb/fitting diameter before purchasing.

Length and Leg Dimensions: For molded elbows, leg lengths determine whether the hose will reach both connection points without extra joins. Check centerline or leg-length specs.

2. Bend Type: Molded vs. Silicone Elbow vs. Bulk Hose

• Molded 90° Hoses: Designed specific to an engine family (e.g., LS swaps) to clear obstructions and reduce fittings. Good where space is tight.
• Silicone Elbows: Offer high-temp tolerance and flexibility. Often universal; useful when vibration, heat, or longevity are concerns.
• Bulk Heater Hose + Fittings: Flexible routing using standard hose with 90° fittings provides versatility for custom setups.

3. Material And Temperature Resistance

Rubber/EPDM: Common in OEM heater hoses, acceptable for standard coolant temps, often resistant to water permeation when high-quality.

Silicone: Wider temperature range and better aging resistance. Consider for high-heat engines or where longevity is a priority.

4. Pressure Rating And Durability

Confirm the hose or elbow’s max pressure rating if operating under elevated system pressures. Reinforced silicone elbows often list PSI ratings suitable for standard cooling systems.

5. Compatibility With Coolant And System Metals

Electrochemical Degradation (ECD): Select hoses engineered to resist ECD when dissimilar metals are present. OEM-style hoses such as Gates list ECD resistance as a feature.

Chemicals and Additives: Ensure material compatibility with your coolant formulation and any corrosion inhibitors used.

6. Clamps, Connections, And Installation

Secure clamping is vital. Some listings include clamps; others do not. Use proper worm-drive or crimp clamps sized for 3/4″ hoses. For molded parts, verify whether additional sealants or O-rings are required with the mating fittings.

7. Application-Specific Considerations

• LS Swaps: Molded LS-specific hoses can simplify routing and reduce interference around water pump outlets and control arms.
• Performance/High-Temp Engines: Prefer reinforced silicone elbows for elevated heat or when turbo/intercooler proximity increases temperature exposure.
• Custom Builds: Use bulk hose plus quality 90° fittings or a combination of silicone elbows and adapters to tailor lengths and angles.

8. Comparison Perspectives

Maintenance Perspective: Silicone elbows generally outlast rubber in age-related cracking tests, but rubber hoses may be easier to splice and more cost-effective for routine replacements.

Space And Fitment Perspective: Molded LS hoses excel where factory ports and tight clearances create interference risks. Universal elbows require checking clearance for leg lengths.

Performance Perspective: Reinforced silicone offers better thermal stability for aggressive cooling systems, whereas OEM-style hoses are engineered for long-term coolant containment and ECD resistance.

9. Final Fit Checklist Before Buying

1. Measure the port inner diameter and length to the mating connection.
2. Verify leg length or centerline length against available clearance and routing path.
3. Confirm material compatibility with intended coolant and operating temperatures.
4. Ensure required clamps or fittings are included or plan to source appropriate clamps.
5. Check whether the part is marketed for specific engine families (e.g., LS) if doing a swap.