Product Description
The FLEECE FPE-34139 5/8 INCH BILLET ALUMINUM UNIVERSAL BLOCK OFF PLUG is a simple but critical upgrade for sealing off unused 5/8" ports in fuel, coolant, transmission, or A/C hard lines. Precision-machined from billet aluminum, this universal plug delivers a tight, leak-free seal that stands up to pressure, vibration, and harsh environments – exactly what you expect from Fleece Performance Engineering and CPP Diesel.
- Universal 5/8" billet aluminum block off plug for fuel, coolant, and A/C hard-line applications
- Machined from high-quality billet aluminum for strength and corrosion resistance
- Ideal for line deletions, test ports, and custom plumbing on diesel trucks and performance builds
- Compact profile for tight spaces and clean, professional-looking installs
- Backed by the proven quality of Fleece Performance Engineering and CPP Diesel
FEATURES & BENEFITS
- Billet 6061 aluminum construction for durability and long-term corrosion resistance.
- Universal 5/8" line compatibility makes it perfect for capping off unused hard lines on a wide range of diesel and gas applications.
- Clean, professional finish that looks at home in high-end engine bays and custom fabrication projects.
- Simple install – just slide into the 5/8" port and secure with the appropriate clamp or retention method.
- Ideal for deletes and diagnostics when you need to temporarily or permanently block a 5/8" port.
FITMENT DETAILS
The FLEECE FPE-34139 is a universal 5/8" billet aluminum block off plug designed to work in any application that uses a 5/8" hard line or hose port, including:
- Diesel truck fuel system return or supply lines (where 5/8" line is used)
- Automotive and light-truck A/C hard lines (rear A/C delete, line repair, or service work)
- Coolant bypass lines or heater circuits during custom plumbing work
- Transmission, power steering, or auxiliary fluid systems using 5/8" hard lines
- Universal race and fabrication projects requiring a 5/8" line block off solution
Because it is a universal plug, fitment is based on line size (5/8") rather than a specific year/make/model. Always measure the line OD before ordering to confirm compatibility.
CROSS REFERENCE & RECOMMENDED FLEECE COMPONENTS
Build a complete, leak-free plumbing solution by pairing this 5/8" block off plug with other Fleece fittings and block off plugs available at CPP Diesel:
- For smaller ports, see the FLEECE FPE-34070 3/8 INCH BILLET ALUMINUM UNIVERSAL BLOCK OFF PLUG .
- For mid-size ports, step up to the FLEECE FPE-34071 1/2 INCH BILLET ALUMINUM UNIVERSAL BLOCK OFF PLUG .
- For larger block off needs, use the FLEECE FPE-34113 7/8 INCH BILLET ALUMINUM UNIVERSAL BLOCK OFF PLUG .
- For turbo oil drain and hose connections that pair well with 5/8" style plumbing, check out the FLEECE FPE-34131 UNIVERSAL TURBO DRAIN NIPPLE WITH INTEGRATED O-RING SEAL 7/8 INCH HOSE .
- For high-quality AN-style fittings in the same system, consider:
SPECIFICATIONS FOR FLEECE FPE-34139
| Specification | Detail |
|---|---|
| Brand | Fleece Performance Engineering |
| Part Number | FPE-34139 |
| Product Type | Universal 5/8" line block off plug |
| Material | Billet 6061 aluminum |
| Line Size | 5/8" universal hard line / hose applications |
| Finish | Machined aluminum |
| UPC | 635909312130 |
| GTIN | 00635909312130 |
| Country of Origin | USA (as listed by multiple distributors) |
| Cross Reference | FPE-34070 (3/8" billet plug), FPE-34071 (1/2" billet plug), FPE-34113 (7/8" billet plug), FPE-34131 (turbo drain nipple), FPE-34873-A, FPE-34805-A, FPE-NPT-18-ORING |
| E-Codes / Emissions | Not emissions controlling; no specific E-code applicable (universal plumbing component) |
| Prop 65 Warning | WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov |
| Shipping Info | Ships from CPP Diesel via standard ground service; expedited options available at checkout. Small, lightweight item ships economically and can be combined with other Fleece fittings and hardware. |
FREQUENTLY ASKED QUESTIONS
What does the FLEECE FPE-34139 block off plug actually do?
This plug is designed to seal off any unused 5/8" line or port, such as fuel return lines, coolant bypass ports, or A/C hard lines. It prevents fluid or refrigerant leaks and keeps contaminants out of the system when a line has been deleted, relocated, or temporarily disconnected.
Is this block off plug vehicle-specific?
No – the FPE-34139 is a universal 5/8" plug. Fitment is determined by line size, not by year/make/model. As long as the port or line you are sealing is 5/8" and physically accepts the plug, it can be used on virtually any diesel or gas application.
Can I use this plug on fuel, coolant, or transmission lines?
Yes. The billet aluminum construction makes it suitable for fuel, coolant, and other compatible automotive fluids when used in a proper 5/8" line. Always verify the system pressure and make sure the plug is secured with the correct clamp or retention method for your application.
How does this plug compare to other Fleece block off plugs?
The FPE-34139 is the 5/8" size in Fleece’s billet block off plug family. If you need a smaller or larger diameter, consider:
- FPE-34070 for 3/8" lines
- FPE-34071 for 1/2" lines
- FPE-34113 for 7/8" lines
All of them share the same high-quality billet construction and are available from CPP Diesel.
Is any special maintenance required for this billet plug?
Maintenance is minimal. Periodically inspect the plug and surrounding line during routine service intervals to confirm there are no leaks or signs of abrasion. In harsh environments, a quick wipe-down can help preserve the clean billet finish, but no other special care is required.
