Buy Genuine Cummins 1 Cylinder Air Compressor EL850 - wisentpartscenter.com

Description

Genuine Cummins 3912500 EL850 Air Compressor is a single-cylinder, gear-driven compressor used to supply compressed air for the truck’s air-brake and pneumatic systems. This water-cooled EL850 design mounts directly to the engine and is driven mechanically, allowing it to build and maintain system air pressure whenever the engine is running.

Key Functions
- Supplies compressed air for the vehicle’s air-brake system and other pneumatic equipment.
- Uses a gear-driven design for continuous operation with the engine.
- Water cooling helps control compressor temperature during extended duty.
- Builds air pressure as system demand increases and works with the governor to control loading and unloading.

Fitment & Specifications
- Compressor Series: Haldex/Midland EL850
- Cylinder Configuration: Single cylinder
- Mounting: 2-hole flange
- Drive: Gear driven
- Shaft: Tapered
- Cooling: Water cooled
- Rated Displacement: 8.5 CFM @ 1,250 RPM
- Bore: 3.15 in
- Stroke: 1.50 in
- Maximum Turbo-Charge Pressure: 25 PSI
- Overall Height: 11.44 in
- Overall Width: 4.76 in
- Overall Length: 8.86 in
- External Shaft Length: 2.22 in
- Approximate Weight: 31 lb

Verify fitment with us before ordering to ensure the correct part for your application.

Purpose of the Part

The 3912500 keeps the truck’s air system supplied with compressed air while the engine is running. That air is stored in the vehicle’s reservoirs and used by the braking system and other pneumatic equipment, with the governor controlling when the compressor loads and unloads as system pressure changes.

Issue Symptoms / When to Replace

A worn compressor may take too long to build air pressure, struggle to recover pressure after repeated brake applications, pass excessive oil into the discharge line or air dryer, or develop abnormal mechanical noise. Coolant or oil leakage around the compressor can also indicate a problem. Before replacing it, the governor, air dryer, discharge line, intake supply, and system air leaks should be checked because they can create similar slow-build symptoms.

Brand Information

Cummins has produced diesel engines and engine-mounted components for more than a century. This compressor belongs to the EL850 family developed under the Midland/Haldex commercial-vehicle air-compressor line, and Haldex’s own catalog specifically documents the 2-hole, water-cooled EL850 configuration for Cummins B-engine applications.

Installation Notes

Disconnect the negative battery cable and drain coolant below the compressor level before removal. Make sure the oil supply and coolant passages are clean and unrestricted, then use the engine-specific Cummins procedure for drive installation and mounting torque.

How to Identify an OEM Part

Haldex manufactures this compressor for Cummins. Genuine/OE units can be identified by the Haldex/Cummins manufacturer markings and the casting numbers permanently cast into the compressor housing.

Why Buy 3912500 from Wisent Parts

  • ⏱️
    Fast shipping
    Orders before 12PM EST ship same business day.
  • 🛡️
    180-day warranty
    All parts covered from delivery date.
  • ↩️
    Easy returns
    30-day returns.
  • ✅
    Verify fitment
    Send VIN/ESN and we’ll confirm.

Shop with confidence

Warranty & Return Information
Warranty Information

Wisent Parts offers a 180-day warranty on all parts from the date of delivery. This warranty covers orders placed directly through our website. If a part fails during this period, we’re here to help - whether it’s a replacement, repair, or refund. For full details, refer to the Warranty page.

Return Information

Wisent Parts accepts returns within 30 days of delivery. All returns are subject to a restocking fee. To qualify, parts must be unused and in their original condition. For full return instructions and restocking fee details, please refer to the Returns page.