The part number 951 123 138 01 is a genuine Porsche component primarily used in certain air-cooled models. If you're searching for this number, you likely need a specific replacement or want to confirm its application. This guide explains what the part is, which Porsche models it fits, and how to source a reliable replacement.
What Is the 951 123 138 01 Porsche Part?
951 123 138 01 is an original equipment manufacturer (OEM) part number assigned by Porsche. It corresponds to a fuel hose or fuel line component used in the engine bay. More specifically, it is a fuel return line that connects the fuel pressure regulator to the fuel tank or another part of the fuel system. The part is made of reinforced rubber or synthetic material to withstand high pressure and resistance to fuel degradation.
Common Names for This Component
- Fuel return hose
- Pressure line (fuel system)
- Engine bay fuel hose
- 951.123.138.01 (Porsche format)
Which Porsche Models Use the 951 123 138 01 Part?
This part was used primarily in Porsche 944 models from the mid-1980s through early 1990s, specifically the 944 Turbo (often called 951 internally) and some naturally aspirated 944 variants. The "951" prefix indicates the 944 Turbo platform. It may also appear in certain Porsche 924 or 968 models, but the 944 Turbo is the most common application.
Fitment List
- Porsche 944 Turbo (1986–1991) – most common
- Porsche 944 S2 (1989–1991) – possible use
- Porsche 968 (1992–1995) – limited use, check part cross-reference
- Porsche 924 Turbo (early models) – verify with VIN
Always confirm fitment using your vehicle's VIN number or consult the parts catalog for your specific model year.
How to Identify the 951 123 138 01 Part
When inspecting the part, look for the following characteristics:
- Shape: A rubber hose with molded bends; typically about 10–12 inches long with a 90-degree or angled end.
- Diameter: Approximately 8 mm inner diameter (5/16 inch).
- Markings: The part number may be printed on the hose or on a small tag. However, original Porsche hoses often lack visible numbers after years of heat exposure.
- Location: In the engine bay, near the fuel rail or pressure regulator, connecting to a metal line going toward the firewall or fuel tank.
Symptoms of a Failing 951 123 138 01
- Visible cracks, swelling, or fuel odor
- Fuel leaks (especially after engine is warm)
- Engine running rich (unburned fuel smell)
- Check engine light related to fuel pressure (not common but possible)
If you notice any of these, replace the hose immediately to avoid fire risk or fuel system damage.
Replacement Options for 951 123 138 01
You have two main choices: OEM Porsche or aftermarket equivalent. Each has pros and cons.
OEM Porsche Fuel Hose
- Exact fit and materials as original
- Guaranteed to meet Porsche specifications
- Higher cost – typically $50–$90 depending on dealer or online retailer
- Available from Porsche dealerships or specialized Porsche parts suppliers
Aftermarket Replacement
- Lower cost – often $15–$30
- Must be rated for fuel injection use (high pressure, ethanol resistance)
- Requires careful measurement and cutting; may not have pre-formed bends
- Quality varies by brand; look for reputable manufacturers like Gates, Dayco, or continental
- Can be a DIY alternative if you have the right tools and know-how
Recommendation: For critical fuel system components, OEM is safer. The cost difference is small compared to potential engine damage or fire.
How to Replace the 951 123 138 01 Part
Replacing this fuel hose is a moderate DIY task. Basic mechanical skill and care are required. Always work in a well-ventilated area with the engine cold.
Tools and Materials Needed
- New 951 123 138 01 hose (or equivalent)
- Fuel line disconnect tool (for quick-connect fittings, if equipped)
- Flathead screwdriver (to loosen clamps)
- New hose clamps (preferably fuel-injection rated)
- Safety glasses and gloves
- Fire extinguisher nearby
Step-by-Step Replacement
- Relieve fuel system pressure: Disconnect the fuel pump relay or fuse, then crank the engine a few times to reduce pressure. Or loosen the fuel cap to vent tank pressure.
- Locate the hose: Find the 951 123 138 01 hose between the fuel pressure regulator and the metal return line. It is often near the intake manifold.
- Remove old hose: Use a screwdriver to loosen the clamps at both ends. Carefully pull the hose off. Some may be stuck; twist gently to break the seal.
- Install new hose: Slide the new hose onto the fittings, ensuring it goes past the barb or nipple. For pre-formed OEM hoses, line up the bends correctly.
- Secure with clamps: Tighten clamps securely, but don't overtighten – rubber can be damaged. Use recommended torque if available.
- Reconnect fuel pump relay: Reinstall the relay or fuse. Turn the ignition on (without starting) to pressurize the system and check for leaks. Use a flashlight to inspect all connections.
- Test drive: After confirming no leaks, start the engine and let it idle. Check again for leaks under moderate revs.
If you are not confident working with fuel systems, have a qualified mechanic perform the replacement.
Where to Buy the 951 123 138 01 Part
Avoid general marketplaces that may sell counterfeit or low-quality parts. Stick to reputable sources:
- Porsche dealerships: Safest option, but often highest price.
- Specialized Porsche parts retailers: Companies like Pelican Parts, FCP Euro, or ECS Tuning stock genuine and quality aftermarket parts.
- Online Porsche forums: Some members sell unused OEM parts; verify condition and authenticity.
- Local auto parts stores: May carry compatible hose but not the exact pre-formed piece – you may need to cut and route it yourself.
Check if the part is in stock: Due to its age, availability can vary. Some aftermarket alternatives are constantly produced, while OEM hoses may be on backorder. Plan ahead.
Final Recommendation
For the 951 123 138 01 Porsche part, the best choice for most owners is the genuine OEM fuel hose. It ensures perfect fit and proper material resistance. If you are on a tight budget or need a quick fix, a high-quality aftermarket hose rated for fuel injection is acceptable, but measure carefully and use fuel-rated clamps. Regardless of choice, inspect the hose annually for cracks or leaks. This small component is critical to your Porsche's reliability and safety.
If you're unsure about the exact part for your vehicle, use your VIN to double-check with a Porsche dealer or parts specialist. Replacing a failing fuel hose early can prevent a breakdown or a dangerous engine fire.