One Piece Thermostat Housing Kit For 2001-2005 LB7 / LLY Duramax

HSP One Piece Thermostat Housing Kit for 2001-2005 Chevrolet / GMC Duramax LB7 / LLY

The 040-HSP One Piece Thermostat Housing Kit is designed for 2001-2005 Chevrolet and GMC Duramax LB7 and LLY trucks. This forward-facing thermostat housing is a major upgrade for trucks running aftermarket turbos, dual CP3 systems, or custom engine bay layouts. It simplifies coolant routing, increases under-hood clearance, and dramatically improves serviceability and aesthetics.

Why Choose the HSP Thermostat Housing Kit?

Factory coolant routing on LB7 and LLY trucks is restrictive and often interferes with performance modifications. The OEM coolant hose runs across the driver-side valve cover, creating constant clearance issues especially with upgraded turbos or dual fuel setups. The HSP Thermostat Housing Kit removes these limitations by redesigning the coolant exit path for significantly improved workspace and routing flexibility.

What Makes It Different?

Unlike the stock unit, the HSP housing reroutes coolant away from the valve cover area, providing room for:

• Aftermarket and custom turbo systems
• Dual CP3 fuel pump kits
• SImplified maintenance access
• Cleaner, more organized engine bay layouts

Each unit is CNC-machined from aluminum and paired with a powder-coated hard tube for exceptional durability and visual appeal.

What's Included

• 1x Aluminum Thermostat Housing (HSP-IN-716-C)
• 1x Radiator Hose Tube w/ Logo (HSP-IN-229)
• 1x M8x1.25-25mm Socket Cap Bolt (RFB-909-RFAB)
• 3x M8x1.25-45mm Socket Cap Bolt (RFB-1032-RFAB)
• 18" of 3/8" Heater Hose (RFB-395-RFAB)
• 2x 1/2" Worm Gear Clamp (RFB-405-RFAB)
• 4x 1-3/4" T-Bolt Clamp (RFB-426-RFAB)
• 1x 1.75" 90° Rubber Boot (RFB-433-RFAB)
• 1x 1.75" x 3" Straight Rubber Boot (RFB-437-RFAB)
• 1x Metric Bonded Seal 14mm (RFB-455-RFAB)
• 1x M14x1.5 to 3/8" Hose Barb (RFB-692-RFAB)
• 1x M14x1.5 Port Plug (RFB-969-RFAB)
• 3x M6x1.0x35mm Flange Bolts (RFB-914-RFAB)
• 6x M6 Fender Washers (RFB-915-RFAB)
• 3x M6 Nylon Lock Nut (RFB-916-RFAB)

Vehicle Fitment

• LB7: 2001-2004 (VIN Code 1)
• LLY: 2004.5-2005 (VIN Code 2)

How to Identify VIN Code

The engine code is determined by the 8th character of the VIN number.
The model year is determined by the 10th character.

Overview

• CNC-machined aluminum thermostat upper housing
• Creates additional clearance for aftermarket turbochargers
• Improves access to driver-side fuel system components
• Includes powder-coated hard tube for a cleaner engine bay
• Compatible with dual CP3 pump kits
• Multiple powder coat and custom finish options
• Ideal for high-power or custom turbocharger configurations

Our Warranty

HSP NO BS LIMITED LIFETIME WARRANTY

At HSP, we believe in our products and stand behind every one that leaves our facility. For years, we've gone above and beyond for customers even without a formal policy. With the HSP No BS Limited Lifetime Warranty, that same commitment is now set in stone. We aim to provide clarity, dependability, and support throughout every step of ownership.

For more information about our Lifetime, No BS Warranty, click HERE.