A truck intercooler is essentially a compact heat exchanger designed to remove heat from compressed intake air before it enters the engine.

After the turbocharger compresses intake air its pressure increases and temperature rises significantly. This hot air flows into the intercooler inlet.

Inside the intercooler core, the air is routed through a network of cooling tubes/ channels. These tubes have a large internal surface area that maximises heat transfer. Flow is designed to be turbulent as it travels through the internal fins of the tubes, which improves heat exchange by constantly mixing hotter and cooler air layers.

At the same time ambient air, from vehicle motion and/ or a cooling fan, flows across the outside of the intercooler.

Heat transfer occurs via:

• Conduction: Heat moves from hot charge air to the tube walls.
• Convection (internal): From air to tube surface.
• Convection (external): From tube surface to passing ambient air.

A failing or leaking intercooler (or its piping and hoses) results in increased fuel consumption, reduced performance, and visible leaks.

Symptoms of a Bad Intercooler:

• Poor fuel economy: Engine compensates for lost air by injecting more fuel.
• Loss of power: Slower acceleration, especially when boosting. Feels like the turbo isn’t working properly.
• Reduced boost pressure: Lower than normal boost readings (if you have a gauge). Turbo may spool but not deliver expected pressure.
• Hissing/ whooshing noise: Air escaping under boost. Often louder during acceleration.
• Black smoke (diesel engines): Too much fuel, not enough air. Unburnt fuel exits as black exhaust smoke.
• Oil around intercooler or pipes: Wet, oily patches at joints, hoses, or the intercooler core. Oil mist in the intake system escapes through the leak.
• Check engine light, fault codes related to:
  • Low boost pressure.
  • Airflow imbalance.
• Limp mode (in some vehicles): ECU limits power to protect the engine when boost is too low.
• Rough or inconsistent performance under load: Hesitation or uneven acceleration when the turbo kicks in.

Should any of the above symptoms be present on your vehicle then it is recommended that an Intercooler/ Charge Air Cooler test be performed without delay.

Charge Air Cooler Test

A charge air cooler (CAC) test is a pressure test of the turbo intake system used to check for air leaks, cracks, or weak components between the turbocharger and the engine. It’s one of the most important diagnostic tests on turbocharged diesel engines, especially on semi-trucks.

A Charge Air Cooler Test verifies that the entire boost system can hold pressure. If the system can’t hold pressure, you’re losing boost, losing power, and using more fuel.

Charge Air Cooler Tester

The Dura-Lite™ Charge Air Cooler Tester-Kit™ is a professional pressure-testing tool designed to check for boost leaks in the charge air system (intercooler and piping) on turbo diesel engines.

A Dura-Lite Tester-Kit includes everything needed to test most truck CAC systems:

• Multiple rubber test plugs (various sizes).
• Plug stems, tightening handles, and washers.
• Safety clamp assemblies.
• Pressure gauge assembly.
• Lubricant bottle (for maintenance).
• Instructions.

Buy a Dura-Lite Intercooler Tester-Kit Online Now

How To Test A Charge Air Cooler

Here’s a helpful video that demonstrates how to use the Dura-Lite Charge Air Cooler Tester Kit step-by-step. It walks through:

• Installing rubber plugs on the inlet/ outlet ports.
• Securing safety clamps and attaching the pressure gauge.
• Pressurising and then observing if the pressure holds.
• Checking the pressure drop to identify leaks.

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