• A silver-colored metal heater bypass blockoff with a manual valve wheel, against a white background with the 'Jaywire Solutions' logo at the bottom.
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Jay Wire Solutions

Heater Bypass Blockoff

Heater Bypass Blockoff

$30.00 USD
$30.00 USD
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LS Water Pump Heater Bypass Blockoff – Thermostat Replacement

The heater bypass blockoff is designed to replace the thermostat in an OE-style LS water pump, helping you optimize coolant flow in high-performance or custom cooling systems.

When paired with properly routed heater core lines, this blockoff prioritizes suction of cool water from the radiator and directs coolant flow back to the radiator—helping you maintain more stable and consistent engine temps, especially in racing or high-load conditions.

Note: Gasket not included, but available separately.
Learn more about how this system works: ➡️ Watch the video

Product Details

  • Application: Replaces thermostat in OE LS water pumps
  • Function: Prioritizes radiator-to-engine coolant flow
  • Cooling Benefit: Promotes stable temps by ensuring cooled water from radiator reaches engine
  • Use Case: Ideal for racing, custom cooling systems, or heater core line deletes
  • Gasket: Not included (optional add-on)
  • Installation: Simple drop-in replacement for thermostat
  • Educational Video: YouTube overview
View full details

Customer Reviews

Based on 4 reviews
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eric fasnacht
Heater Bypass Blockoff

I was having issues with water temps in the LS in my Drag and Drive car. I was talking to a buddy of mine and he reminded me of a discussion we had with some guys that we pitted next to during Sick Week 2024 in which they explained a fix they came up with for their LS Nova. I ordered a block off plate and my temps went from 195+ degrees to 160 degrees. Thanks for the help Jay.

User picture
J
Justin
Gave my cooling system much needed help

Put it in my LS swapped Fox that had issues staying cool. Gotta remember to block off the heater core and not loop it. More people should know about this.

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Dennis Begyn
Innovative Mind

This company has the visions to create the solutions that all off the performance industry needs.
Thank you JAY!

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Andrew B.
Best $30 Spent!

This little gadget should be on the list for every LS car that isn't running heat. Absolute game changer for cooling, especially in turbo street car applications that tend to have excess engine bay heat. Much better operating temps, less dependence on the fan, and makes bleeding air from the system INCREDIBLY easy