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Keep Vintage WRX Cooling Systems Running Strong
Early Subaru WRX and STI models have plenty of miles on their factory coolant hoses by now, and rubber that has seen years of heat cycles is prone to soft spots, expansion, and sudden failure. The GRMGRM405329 GrimmSpeed Radiator Hose Kit is built to replace those tired factory hoses with a 5 ply reinforced silicone design that resists heat and pressure far better than stock rubber. The GRMGRM405329 kit is 3D scanned for a precise factory style fit, so installation is Make this 1000x1000 on a white background without any trimming or kinking. For owners running more boost than stock, the GRMGRM405329 gives extra peace of mind under the hood.
Key Features
- 5 ply silicone construction with fiber reinforcement between every layer
- 3D scanned for a precise factory style fit on GRMGRM405329 applications
- Includes upper hose, lower hose, and four stainless steel BREEZE high torque clamps
- Embedded GrimmSpeed logo on each hose
- Available in a vibrant red finish for engine bay styling
Fitment Table
| Year Range | Make | Model | Trim |
|---|---|---|---|
| 2002-2007 | Subaru | WRX | |
| 2004-2007 | Subaru | WRX STI |
Specifications
| Detail | Value |
|---|---|
| Part Number | GRMGRM405329 |
| UPC | Not published by manufacturer |
| Color | Red |
| Material | Reinforced Silicone |
| Number of Hoses | 2 (upper and lower) |
| Clamps Included | Yes, 4 stainless steel BREEZE clamps |
| Brand | GrimmSpeed |
What's Included
- 1 upper silicone radiator hose
- 1 lower silicone radiator hose
- 4 stainless steel high torque BREEZE hose clamps
About GrimmSpeed
GrimmSpeed started as a small garage operation in Minneapolis, Minnesota in 2006 and has grown into one of the most trusted names in Subaru performance. What began with a focus on WRX and STI parts has expanded to Mitsubishi, Ford, MazdaSpeed, and Hyundai platforms, but the engineering philosophy has stayed the same: build parts that are tougher, smarter, and better finished than anything else on the market.
FAQ
What is the GRMGRM405329?
The GRMGRM405329 is a GrimmSpeed silicone radiator hose kit built for the 2002-2007 Subaru WRX and 2004-2007 Subaru WRX STI. It replaces the factory upper and lower coolant hoses with a 5 ply reinforced silicone design and includes new stainless clamps.
Does the GRMGRM405329 require any cutting or trimming during install?
No. The GRMGRM405329 hoses are 3D scanned from factory hoses, so they match the stock routing and length without any modification.
What color options are available for the GRMGRM405329?
The GRMGRM405329 is offered in a red silicone finish with an embedded GrimmSpeed logo.
Are hose clamps included with the GRMGRM405329?
Yes. Every GRMGRM405329 kit ships with four stainless steel high torque clamps from BREEZE.
Why upgrade to the GRMGRM405329 over stock hoses?
Factory rubber hoses on early WRX and STI models are now well over a decade old in many cases. The GRMGRM405329 uses a 5 ply silicone build that resists the heat and pressure that cause factory rubber to expand and fail.
Is the GRMGRM405329 a direct fit replacement?
Yes. The GRMGRM405329 is designed as a direct bolt in replacement for the factory upper and lower radiator hoses on supported models.
How many hoses come in the GRMGRM405329 kit?
The GRMGRM405329 kit includes two hoses, one upper and one lower, along with the mounting clamps.
Can the GRMGRM405329 handle track use?
Yes. The reinforced silicone construction of the GRMGRM405329 is built to withstand the higher temperatures and pressures seen in spirited driving and track sessions.
Install Instructions
- Allow the engine to cool completely and relieve pressure from the cooling system before starting.
- Drain the coolant into an approved container.
- Loosen and remove the factory clamps and hoses from the radiator and engine connections.
- Install the new GRMGRM405329 upper and lower hoses in the same routing as the factory hoses.
- Secure each connection with the included BREEZE stainless clamps.
- Refill the cooling system with the manufacturer specified coolant.
- Start the engine and check for leaks, then top off coolant as needed once the system has cycled.
Prop 65 Warning
Operating, servicing, and maintaining a passenger vehicle or off road vehicle can expose you to chemicals including engine exhaust, carbon monoxide, phthalates, and lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. To minimize exposure, avoid breathing exhaust, do not idle the engine except as necessary, service the vehicle in a well ventilated area, and wear gloves or wash hands frequently when servicing the vehicle. For more information visit www.P65Warnings.ca.gov/passenger-vehicle
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