Cummins 3929108 — Genuine Intake Air Heater Grid for 5.9L 12-Valve

MPN: 3929108  |  Also Known As: grid heater, intake air heater, heater element

Genuine Cummins intake air heater grid that preheats incoming air to improve cold starts, reduce white smoke, and stabilize idle on mechanical 5.9L applications. Direct-fit for 1989–1998 5.9L 12-valve (see compatibility notes for 24-valve & common-rail differences). Sold individually (1 per engine).

Features & Benefits

• OE heating performance for reliable cold-weather starting.
• Direct-fit replacement for 5.9L 12V intake horn/plenum interface.
• Heavy-duty element for fast warm-up and durability.
• Reduces white smoke and misfire on cold starts.
• Built to Cummins standards for fit, function, and longevity.

Verified Fitment (Automotive)

Industrial/Off-Highway: Used on various B-Series platforms including 4B3.9 / B5.9 / ISB/QSB variants—verify by ESN prior to ordering.

Specifications

• Type: Intake air heater grid (electric heating element)
• OE Part Number: 3929108
• Quantity Required: 1 per engine (sold individually)

Often Paired With

• Intake heater grid gasket: 3969988 (quantity varies by application; typically one for 12V)
• Spacer / additional gasket options (by setup): 3913352, 4429352, Mopar 5010480AA/AB, 5086721AA/AB

What’s In The Box

• (1) Genuine Cummins Intake Air Heater Grid (3929108)
• Gaskets/hardware sold separately (see “Often Paired With”).

Installation Tips

• Disconnect batteries before service; verify relay operation and wiring integrity.
• Clean mating surfaces; use new gasket(s) and torque to spec.
• Verify grid activation and voltage drop after install; inspect for air leaks.

FAQ

WILL THIS FIT MY 1989–1998 5.9L 12-VALVE?

Yes—3929108 is the OE grid heater for most 1989–1998 5.9L 12-valve applications. Check your intake/plenum style to confirm (integrated vs. separate).

WILL THIS FIT 24-VALVE (1998.5–2002) OR COMMON-RAIL (2003–2007)?

No—those engines typically use a different grid heater assembly (e.g., 3969987 on many 24-valve trucks) and different gasket counts.

HOW MANY GASKETS DO I NEED?

12-valve setups usually use one 3969988 gasket at the grid. Some later configurations (24V/CR) use two gaskets—confirm your setup.

WHAT ARE THE SIGNS OF A FAILED GRID HEATER?

Hard cold starts, white smoke on start-up, or diagnostic checks showing no grid activation/current draw.

IS THIS A GENUINE CUMMINS PART?

Yes—OE Cummins part 3929108 for proper fit and durability.