Baldwin B421 Engine Oil Filter

Baldwin B421 Engine Oil Filter for Isuzu

The Baldwin B421 is an engine oil filter built for select Isuzu Automotive applications. It uses an anti-drainback valve and a 14 PSID by-pass valve to support oil flow control during start-up and under restricted-flow conditions. This Baldwin B421 oil filter is a direct replacement for OE part number 8-94430-411-1.

Key Features

• Engine oil filter for select Isuzu Automotive vehicles
• Contains an anti-drainback valve
• 14 PSID by-pass valve
• Thread size: M20 x 1.5
• Height: 2 27/32 in. (72.2 mm)
• Outside diameter: 3 in. (76.2 mm)
• Integral gasket included
• Replaces Isuzu 8-94430-411-1

Detailed Description

The Baldwin B421 is an OE-style engine oil filter for Isuzu Amigo, Pickup, Rodeo, Trooper, and Impulse applications. Its anti-drainback valve helps retain oil in the filter after shutdown, while the 14 PSID by-pass valve provides a controlled path for oil flow when the filter media reaches a restriction threshold. With an M20 x 1.5 thread, 2 27/32-inch height, and 3-inch outside diameter, the B421 is sized for the listed Isuzu fitments and matches the OE reference 8-94430-411-1. This Baldwin B421 filter is a practical choice for routine oil service on Isuzu engines that use this specification.

Vehicle Fitment

• Fits 1989-1993 Isuzu Amigo, N/A
• Fits 1988-1993 Isuzu Pickup, N/A
• Fits 1991-1993 Isuzu Rodeo, N/A
• Fits 1989-1993 Isuzu Trooper, N/A
• Fits 1992 Isuzu Impulse, N/A (OE Number: 8944304111)
• Fits 1990 Isuzu Impulse, N/A

Common Service Issues Addressed

• Oil filter replacement during scheduled maintenance
• Restoring proper oil filtration after extended service intervals
• Replacing a filter with a worn or damaged gasket
• Addressing oil drain-back concerns after engine shutdown
• Replacing the OE filter referenced as Isuzu 8-94430-411-1

Installation Notes and Tips

Verify the thread size, gasket diameter, and overall filter dimensions before installation. Pre-lubricate the gasket with clean engine oil, tighten the filter to the vehicle manufacturer’s specification, and check for leaks after the first engine start. Confirm the application against the vehicle’s engine code when servicing Isuzu Amigo, Pickup, Rodeo, Trooper, or Impulse models.

Quality Assurance

Baldwin manufactures filtration products for automotive service applications, and the B421 is built to the listed dimensional and valve specifications for the confirmed Isuzu fitments.