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Cummins  |  SKU: 4309439

4309439 | Genuine Cummins® Air Compressor Head Repair Kit

$84500
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Description:
An air compressor head repair kit 4309439 is a set of replacement parts used to fix the top (head) section of an air compressor when it starts losing performance.

Part Number: 4309439, 4309439RX 
Condition: New
Manufacture/Brand: Cummins

Fits 4309439 For NT855, B3.3, B6.7 CM2350 B121B, B6.7 CM2350 B136C, B6.7 CM2350 B157C, B6.7 CM2450 B155B, B6.7N CM2380 B150B, ISB, ISB CM2150, ISB6.7 CM2250, ISB6.7 CM2350 B101, ISBE CM2150, ISBE4 CM850, ISC CM850, ISD6.7 CM2150 SN, ISL CM2150, ISL CM850, ISL G CM2180, ISL9 CM2150 SN, ISL9 CM2350 L101, ISM CM876, ISM11 CM876 SN, K19, K38, L9 CM2350 L116B, L9 CM2350 L119B, L9 CM2350 L120C, L9 CM2350 L129C, L9 CM2350 L133C, L9 CM2450 L126B, L9N CM2380 L124B, L9N CM2380 L142B, QSB3.3 CM2150, QSB6.7 CM2350 B105, QSB6.7 CM850(CM2850), QSC8.3 CM850(CM2850), QSK19 CM500, QSL9 CM2250, QSL9 CM2350 L102, QSL9 CM850(CM2850), QSM11 CM570, QSM11 CM876 M101

Purpose of using 4309439:

  • To restore air pressure
    Replaces worn gaskets and valves so the compressor can build and hold correct pressure.

  • To stop air leaks
    Seals leaks in the compressor head that cause pressure loss and poor performance.

  • To repair damaged intake and exhaust valves
    Fixes broken or weak reed valves that prevent proper airflow.

  • To improve compressor efficiency
    Helps the compressor fill the tank faster and run cooler.

  • To extend the life of the compressor
    Prevents further internal damage by restoring correct operation.

  • To avoid full compressor replacement
    Much cheaper and faster than buying a new compressor.


Signs of a Bad Air Compressor Head Repair Kit 4309439:

  • Compressor still won’t build pressure
    Even after installing the kit, the compressor struggles or fails to reach normal pressure.

  • Air leaking from the head area
    Hissing sounds around the head indicate poor gasket sealing or misaligned parts.

  • Pressure drops quickly after shutdown
    Faulty or incorrectly seated valves allow air to escape back through the head.

  • Long run times or nonstop running
    The compressor keeps running because it can’t maintain pressure.

  • Overheating of the compressor head
    Poor sealing or valve failure causes excess heat buildup.

  • Unusual noises (ticking, popping, fluttering)
    Reed valves may be bent, broken, or installed incorrectly.

  • Oil or moisture leaking from the head
    Gaskets or seals may be damaged or mismatched.

  • Uneven or damaged gaskets found on inspection
    Indicates incorrect torque, poor alignment, or low-quality kit parts.

 

About the Manufacturer – Cummins:

Cummins is a leading American manufacturer of diesel and natural gas engines, as well as power generation systems and emissions solutions. Founded in 1919 and headquartered in Columbus, Indiana, Cummins is known globally for its durable, high-performance engines used in trucks, buses, construction equipment, agriculture, and power systems.

The brand is widely respected for its innovation in clean diesel technology, including aftertreatment systems, turbochargers, and advanced electronics that help reduce emissions while maximizing engine efficiency and reliability.

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