Intercooler Parts

What is the intercooler and where is it located? 

An intercooler is a part used in forced air induction (supercharged or turbocharged) engines to cool down the air from the supercharger or turbocharger before it goes to the intake manifold. 

To understand why an intercooler is useful for forced induction engines, it helps to know how superchargers and turbochargers (turbos for short) work.  Essentially they are fans that compress the air head to the intake manifold.  Superchargers are powered by a belt attached to the crankshaft; turbos are powered by a turbine in the exhaust manifold.  Compressing the air means more air and fuel can be packed into the cylinders for a better combustion and more power. 

When the air gets condensed, though, it gets warmer.  This problem is made worse in turbochargers by the proximity to the hot exhaust gasses.  That prevents it from becoming as dense as it could, and raises the temperature in the cylinders, which can lead to the fuel igniting too early, which causes engine knocking, heard as a metallic pinging sound.  An intercooler cools down the air to keep your supercharger or turbocharger from blowing a lot of hot air. 

There are two common designs for intercoolers: air-to-air intercoolers and air-to-water intercoolers.  An air-to-air intercooler is basically a radiator that the compressed air flows through.  The compressed air enters through a rubber hose, passes through the intercooler, which is usually placed near the engine coolant radiator, and dissipates heat off of the intercooler’s fins into the air before passing on to the intake manifold through another hose. 

An air-to-water intercooler is a bit more complicated.   Compressed air enters a box mounted on top of the engine.  Inside that box is the intercooler itself, a radiator that coolant flows through.  The coolant takes on heat from the air and flows to either the main engine radiator or a dedicated heat exchanger mounted near the radiator.  The heat exchanger, just like a radiator, dissipates heat into the air. 

How do I know if my intercooler needs to be replaced?            

Either type of intercooler can develop boost leaks.  If air is leaking from the intercooler or its hoses, it will be harder for the supercharger or turbocharger to compress the air.  You might notice that your vehicle isn’t as peppy as it used to be.  You might also hear the supercharger or turbocharger spinning faster than usual as it tries to compensate for the lost pressure.  If your vehicle has a boost gauge on the dash, it may show less boost being produced than normal. 

Air-to-water intercoolers can also develop coolant leaks.  This can make them less effective at cooling the compressed air, leading to decreased boost and horsepower, and possibly engine knocking.  Over time, engine knocking can damage the cylinders.  

Even if you are not experiencing knocking, replacing a leaking intercooler, or leaking intercooler hoses, can restore your engine’s pep. 

Can I replace the intercooler myself?  

Replacing the intercooler itself can be a tricky business.  You might want to leave intercooler replacement to a professional mechanic.  In the case of air-to-air intercoolers, you may have to remove the grille and the radiator, as well as various air intake parts to access it.  To replace an air-to-water intercooler, you will have to disconnect the air intake hoses and the coolant lines.  You may also need to reduce the grille and radiator to access the heat exchanger.  Replacing intercooler hoses should prove to be substantially easier and will be similar to replacing an air intake hose.