What does an intercooler do?

Everything you need to know about intercoolers

Intercoolers, found in turbo or supercharged engines, provide much-needed cooling that improves the performance and efficiency of the engine. Before describing how they work, we’ll first why you might need one.

For the sake of simplicity, we’ll stick to engines that use turbochargers with internal combustion engines for this explanation. A turbocharger engine produces a lot of heat while compressing ambient air, which allows it to squeeze more air into the engine.

More air means you can burn more fuel and get more power (increasing fuel efficiency and reducing waste). That may sound simple enough, but compressed air gets very hot, which makes it lose density and therefore carry less oxygen.

Oxygen is vital for combustion of the fuel and air mixture. The compressed air needs to be cooled to increase density and oxygen — this is where the intercooler comes in.

Natrad has a large range of intercoolers for performance vehicles or engines that need a little extra ‘oomph’. Get in touch with us for expert advice and fantastic service.


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From hot to cold

A forced induction engine is not uncommon in high-performance, modern passenger and commercial vehicle applications. It has many benefits such as being more fuel-efficient and relatively lightweight.

However, all that compressed air can reach over 205° C in extreme conditions. As we mentioned before, hot compressed air isn’t great for combustion. That’s where an intercooler comes in to cool the air temperature.

The intercooler achieves this by cooling the air down before it enters the engine and combustion chamber (this cooling process may differ depending on what kind of intercooler is used).

Types of intercoolers

An intercooler is a heat exchanger, and — much like a radiator — it uses tubes and fins to get rid of unwanted heat. There are two main types of intercoolers:

  1. Air to air intercooler

Air-to-air intercoolers are the most common application for everyday vehicles due to their simplicity. To describe this system:

  • Ambient temperature air enters the turbocharger intake.
  • This air is converted into hot compressed air.
  • Hot compressed air is transferred to the intercooler, where it is cooled before being sent to the engine.
  • Outside air, passing over the exterior of the intercooler, carries away excess heat.

This system usually relies on ambient airflow and additional air ducts from the front of the car to flow through the intercooler and cool the compressed air down, much like a radiator.

Main benefits:

  • No liquid leaks
  • Light-weight
  • Simple system
  • Cost-effective
  • Unlikely to experience heat soak if there is good airflow
  1. Air to liquid intercooler

An air-to-water intercooler is far more complex, but they are becoming increasingly popular in cars due to higher efficiency. The process works like this:

  • Ambient temperature air enters the turbocharger intake.
  • The turbocharger compresses and heats this air.
  • Heated air is sent to the intercooler, which cools the air down before it is sent to the engine
  • At the same time, coolant is also circulating through the intercooler.
  • Liquid coolant is used to carry excess heat away from the intercooler to an external radiator, which sends “new” cold coolant back to the intercooler to aid in further cooling.

Given there are two circuits carrying air or coolant, this usually requires more components and fittings, such as hoses. Therefore, air-to-water intercoolers can be a little expensive but are still highly effective, particularly in applications where vehicle speed may be slower.

One potential problem includes the risk of heat soak, where there is a build-up of residual heat near the engine and not enough cooling ability to reduce the temperature.

This can generally be solved by increasing the flow of coolant so that it can dissipate heat faster.

Main benefits:

  • Highly efficient
  • Efficiency can be exaggerated by using ice or other chemicals for short amounts of time
  • Cooling can be adjusted – does not depend on vehicle speed
  • Can be placed anywhere in the engine bay
  • Shorter routing

Common intercooler faults

As discussed above, there are a few things to watch out for with intercoolers. Luckily, most of these are easy fixes, but it’s not hard to fit a replacement should you need it. Common intercooler faults include (but are not limited to):

  • Leaking hoses (air leaks are less serious than coolant leaks)
  • Failure due to impact damage
  • Installation issues leading to malfunction
  • Overheating or heat soak (due to bad intercooler placement and overreliance on ambient airflow)
  • Coolant contamination from leaks into the system
  • Clogging

Signs and symptoms

  • Noticeable drop in engine power
  • Increased fuel consumption
  • Unnatural smoke from the exhaust system
  • Noticeable coolant leakage (which could indicate other problems, such as radiator failure)

If you’re looking to repair your intercooler, Natrad workshops across Australia can help. If repairing is not a sustainable option, Natrad also has a range of intercooler parts or custom-made alternatives.


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