CHARGE AIR COOLERS

Charge Air Coolers For Peterbilt Trucks

The charge air cooler (CAC) — also called an intercooler — cools the compressed air coming out of the turbocharger before it enters the engine's intake manifold. Denser, cooler air means more oxygen per cylinder charge, which translates directly to better combustion efficiency, more power, and lower EGTs. A leaking or restricted CAC on a PACCAR MX or Cummins ISX will rob your Peterbilt of power and fuel economy and can cause turbo damage from heat soak. We stock replacement charge air coolers for common Peterbilt applications.

Frequently asked questions about charge air coolers

How do I test a charge air cooler for leaks?

The standard shop test is to remove the CAC, cap both inlet and outlet openings, pressurize the core to the manufacturer's specified test pressure (typically 30–45 PSI), and submerge it in water or apply soapy water to the fins and tanks. Bubbles indicate a leak. On-truck pressure testing with the CAC installed is also possible using a CAC pressure test kit and blocking off the intake and outlet boots.

What are the symptoms of a failing charge air cooler?

A leaking CAC typically causes reduced power, increased fuel consumption, black smoke under load, and sometimes a noticeable boost pressure loss on trucks with a boost gauge. Oil mist in the charge air plumbing — from the turbo's compressor side — can coat the internal fins of the CAC and restrict airflow over time, further reducing efficiency even without a structural leak.

Can I repair a charge air cooler, or does it need to be replaced?

Minor leaks in the aluminum tanks can sometimes be repaired by a radiator shop using TIG welding or epoxy repair depending on the location, but core damage and end tank cracks that are extensive typically make replacement more cost-effective. Given the labor involved in R&R and the price of replacement CACs relative to a failed repair, most fleets opt for outright replacement on high-mileage cores.

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