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Engine Bay Upgrade That Actually Holds Up to Boost
Stop staring at a cracked, faded factory thermostat housing every time you pop the hood. The WCF100188 from Wehrli Custom Fabrication swaps in a CNC machined billet aluminum housing finished in durable WCFab Red powder coat, built specifically for the 2017-2025 6.6L L5P Duramax. It is a direct bolt-in replacement that cleans up the engine bay while giving you a stronger, more reliable coolant connection point than the OEM plastic unit.
Key Features
- Direct replacement for the factory L5P thermostat housing
- CNC machined from billet aluminum for long-term durability
- Custom WCFab Red powder coat finish resists fading and chipping
- Completes the look when paired with a WCFab Upper Coolant Pipe or Intake Kit
- Bolts on with no cutting or permanent modification required
- Part number WCF100188 engineered and manufactured in the USA
Vehicle Fitment
| Year Range | Make | Model |
|---|---|---|
| 2017-2025 | Chevrolet | Silverado 2500HD |
| 2017-2025 | Chevrolet | Silverado 3500HD |
| 2017-2025 | GMC | Sierra 2500HD |
| 2017-2025 | GMC | Sierra 3500HD |
Fits any 2017-2025 truck equipped with the 6.6L L5P Duramax diesel engine. Always confirm your engine code before ordering the WCF100188.
Specifications
| Detail | Value |
|---|---|
| Manufacturer Part Number | WCF100188 |
| Brand | Wehrli Custom Fabrication |
| Material | Billet Aluminum |
| Finish | WCFab Red Powder Coat |
| Weight | 3.0 lbs |
| Dimensions | 8 in x 8 in x 8 in |
| Engine Application | 6.6L L5P Duramax |
| Condition | New |
What's Included
- 1x Wehrli WCF100188 Billet Thermostat Housing in WCFab Red
- Mounting hardware
- Required gaskets and seals for installation
About Wehrli Custom Fabrication
Wehrli Custom Fabrication, known as WCFab, has spent years building precision diesel performance parts for Duramax, Power Stroke, and Cummins platforms. Every WCFab housing is CNC machined in house and powder coated to a standard that holds up to years of engine bay heat cycling, making it a favorite among diesel truck owners who want factory-fit parts with a serious upgrade in both looks and durability.
Frequently Asked Questions
What is the WCF100188?The WCF100188 is a billet aluminum thermostat housing from Wehrli Custom Fabrication built as a direct replacement for the factory thermostat housing on the 2017-2025 6.6L L5P Duramax. It comes finished in WCFab Red powder coat.
Will this fit my truck if I already installed an aftermarket intake or coolant pipe?Yes, this housing is designed to pair with other WCFab cooling and intake components, so it will not conflict with an existing WCFab Upper Coolant Pipe or Intake Kit.
Do I need to replace the thermostat itself when installing this housing?You can reuse your existing thermostat as long as it is in good working condition, though many customers choose to install a fresh thermostat at the same time since the housing is already off the engine.
Does installing this require special tools?No special tools are needed. Basic hand tools and a standard socket set are sufficient for a home garage install.
Will I need to drain my coolant to install this?Yes, you will need to drain the coolant system before removing the factory housing, then refill and bleed the system after installation.
Is this housing compatible with other powder coat colors if I already have red accents?WCFab offers this housing in multiple finish options including WCFab Grey, Candy Teal, Gloss White, and Gloss Black, so you can match your existing engine bay theme.
Does this come with a warranty?Wehrli Custom Fabrication backs this housing against manufacturing defects. Contact us with your order details if you run into any fitment or quality issues.
Can I return this if it does not fit my truck?Yes, unused parts in original condition can be returned within our standard return window. Reach out to our support team to start the process.
Do I need an alignment or tuning update after installing this housing?No, this is a cooling system component only and does not affect alignment or require a tune change.
Install Instructions
- Allow the engine to fully cool before starting any coolant system work
- Drain the coolant system into an approved container
- Remove the factory upper coolant pipe or hose connections from the OEM thermostat housing
- Unbolt and remove the OEM thermostat housing
- Transfer the thermostat to the new WCF100188 housing or install a new thermostat
- Install new gaskets and bolt the WCF100188 housing into place
- Reconnect coolant lines and hoses
- Refill the coolant system and bleed air from the lines
- Start the engine and check for leaks before closing the hood
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