TINWID1919 3" Fuel Cap for Volvo & Mack Trucks - Non-Locking Non-Vented, OEM Fit (Replaces 20770691/20770657)

TINWID1919's 3-inch non-locking fuel cap replaces 20770691/20770657 for select Volvo and Mack diesel tanks, providing a reliable, low-sulfur labeled closure designed to meet OEM fit and function.

This fuel cap is built for heavy-duty trucks that use low-sulfur diesel or PNG tanks from 2010 onward. It is a non-vented, across-threads 3-inch cap engineered to match the original equipment's dimensions and performance requirements so you get a secure seal without unnecessary modifications. The design focuses on compatibility, durability, and straightforward serviceability for fleet or owner-operator needs.

Will this cap fit my Volvo or Mack truck?

The TINWID1919 3” cap fits select Volvo and Mack diesel tanks labeled for low-sulfur diesel or PNG, typically 2010 models and later. Check your tank threading and label to confirm compatibility; the cap replaces part numbers 20770691 and 20770657.

• Fits across-threads 3-inch fuel tank openings
• Compatible with many 2010+ Volvo and Mack low-sulfur labeled tanks
• Direct replacement for part numbers 20770691 and 20770657
• Not vented — requires a vented tank system to relieve pressure

How does the non-locking, non-vented design affect operation?

Being non-locking, this cap allows quick access for routine fueling without keys or extra hardware. Its non-vented construction means the vehicle’s fuel system must include proper venting elsewhere; the cap itself provides a pressure-tight seal to prevent spills and contamination when the tank’s venting is handled by the vehicle.

• Fast removal and installation — no key required
• Tight, across-threads seal reduces leakage and debris entry
• Requires factory or aftermarket tank venting for safe operation
• Simple part swap for maintenance or replacement needs

What materials and standards does this cap meet?

Manufactured to match OEM specifications for fit, form, and function, the cap is produced with durable materials suitable for diesel environments. It’s intended to meet the tolerances and interface points used by Volvo and Mack, ensuring proper seating and longevity under normal commercial use.

• Constructed to OEM-equivalent specifications
• Resistant to diesel exposure and routine wear
• Engineered for repeatable fit on compatible tanks
• Sold as a direct replacement for listed part numbers

How do I confirm this is the right replacement part?

Verify the OEM part number on your current cap or vehicle parts list — 20770691 or 20770657 are the direct cross-references. Measure the fuel filler opening to confirm the 3-inch across-threads size and ensure your tank is labeled low-sulfur diesel or PNG for compatibility.

• Match stamped or printed part numbers 20770691 / 20770657
• Confirm 3" across-threads filler opening dimension
• Check tank label for low-sulfur diesel or PNG designation
• Contact a technician if you’re unsure about tank venting configuration

Who is this for? This TINWID1919 fuel cap is aimed at fleet managers, mechanics, and owner-operators running compatible Volvo and Mack heavy-duty trucks (2010 and later) who need an OEM-style, non-locking replacement. It suits vehicles that rely on the truck’s venting system and require a durable across-threads 3-inch cap that matches part numbers 20770691 and 20770657 for easy service and inventory matching.