Oil In Intercooler: Causes & Fixes Explained

An oil intercooler is designed to cool the intake air before it enters the engine, reduce pressure loss and increase efficiency. With an oil intercooler, it is possible to use a turbo or supercharger for a boost. This can significantly increase the torque.

Oil intercoolers have been used in many applications, from large engines like locomotives to small racing engines, as well as in the cooling systems of cars, including air-cooled engines, which is not readily discerned.

What Does It Mean When You Have Oil In Your Intercooler?

You could have an internal engine failure when oil is in your intercooler. The current thermal performance of the engine will be reduced. There is a risk of fire if oil and gasoline mix. Oil in an intercooler reduces performance.

If oil gets into the passenger compartment of a vehicle, the visual effect is that of oil on the floor; in fact, it may be coolant. If engine performance is lost or the check engine light comes on, you may need engine diagnostic tests to determine the problem.

A car mechanic performing an engine check.

What Causes Oil To Spill Into The Ducts Of The Cooling System?

Below are some of the possible ways by which you might have oil in your intercooler.

1.     Poor quality/damaged intercooler

An intercooler is a high pressure, high temperature device that cools the air going into the engine, thus boosting its performance. The poor quality intercoolers are made with faulty material and can significantly cause the oil leak.

Problems also arise if there’s a leak or the fins (used in the intercooler) are clogged. This leads to the faulty working of the intercooler and may cause oil to pass into the ducts of the cooling system.

2.     Defective oil intercooler

Oil intercoolers are made with a single material that is mixed with oil. Unlike water-based intercoolers, oil intercoolers are susceptible to damage, leading to oil leakage. Oil intercooler damages mainly occur due to an accident resulting in overheating the intercooler.

However, it appears that these problems are pretty rare because they occur in high temperatures.

3.     Over-speeding

If the vehicle is over-speeded, it is possible to have oil in your intercooler as it has a cooling system to condense the hot air from the turbocharger. Overspeed also creates big pressure in the engine; it’s possible that the intercooler is not able to cope with this pressure. Over speed also loses the pressure, reducing the efficiency of the intercooler.

4.     Damaged oil seals

The seals are used to avoid leakage at the joints of the engine and the intercooler. They stop the oil from passing through the intercooler when the seals break, and oil leaks into the intercooler ducting.

Pouring engine oil.

5.     Improper cleaner used on the intercooler

Oil spills on the intercooler can be picked up using the proper type of cleaner, like kerosene or water-based cleaner. Using the proper type of cleaner, like kerosene, is recommended to keep the intercooler in shape.

The problem is that the type of cleaner used in the vehicle may not be either. Cleaners like kerosene stain the intercooler, thus making it visible and causing oil to come in contact with the intercooler ducts. Therefore, the product used is not proper.

6.     Leaking intercooler

This is an easy risk that you can pay attention to check the condition of the air duct of the intercooler. To check for oil in the intercooler, you have to know the color of the oil coming out of it. When the oil comes out of the intercooler, it appears cloudy with a tinge of blue.

It means the intercooler is not free from leaks; it is difficult to find leaks in the intercooler from its position as it has no duct, and not possible to check the actual condition of the intercooler directly, especially if the duct is damaged. The amount of oil is insignificant.

7.     Improperly maintained fuel system

If the fuel system is not properly maintained, it will become so rusty that it will change the color of the fuel. Oil might be present in the fuel system. The fuel system may also have leaks. An improperly maintained fuel system will lead to more oil in the intercooler.

8.     Leak in heater tubes

When there is a leak in the heater tubes, oil tends to enter the intercooler duct due to the action of the heater. This is especially a problem if you have to dive in cold water. There is a risk of the heater tubes leaking into the intercooler. This can cause damage to the engine.

9.     Use kerosene instead of antifreeze to cool the engine

This is an important cause of intercooler leakage and is still a major threat to road safety. When the intercooler is overheated and over-cooled, the sudden heat release may cause a loss of control of the vehicle.

A man having trouble with car engine overheating.

10.     Collision

Body damage can lead to oil leakage into the intercooler. Cars with a collision may also have oil leakage, not just from the intercooler. The intercooler might have rust that may lead to its leakage of oil.

11.     Leaking radiator

If you leak the engine block or the engine is overheated, water may leak into the radiator and then into the intercooler; if a radiator is damaged in an accident, the danger of oil reaching the engine increase.

12.     Oil Leak at Crankshaft

Oil leaks from the crankshaft usually flow from the bearings to lubricate the camshaft. The oil leak from the crankshaft may cause the engine to freeze. This normally involves a crankcase oil leak. The oil will also leak from piston tops and sideways.

How To Clean The Intercooler And Oil-Spilled Pipe

Below are ways of cleaning the intercooler.

1.     Remove the intercooler

When removing the intercooler, it is best to remove the entire pipe. This avoids any problem that may arise in the future. Wear gloves, long sleeves, and eye protection when removing the intercooler. Be specific and detailed when cleaning the intercooler. Ensure that you don’t produce any scratches on the intercooler and other parts to avoid leakages.

2.     Flush the intercooler duct

The duct for the intercooler can be flushed using the hose. This depends on your vehicle’s make and model, so refer to the manual. The process is relatively simple – hook up a water hose or garden hose to the filler cap and run water through the system while the engine runs.

In some cases, the water will come out clean. In others, there may be an orange in color, indicating a problem. If there is orange water in color, it may be due to the water heater system. If this happens, change the heating system. You will have to have the system flushed to eliminate the contaminants.

3.     Use degreasers and gasoline to remove oil

It is always best to use degreasers and gasoline to clean off the oil. This can greatly clean the oil, which will cause rust on the intercooler and engine. Other chemicals like kerosene and acetone can be used as well.

4.     Use a pressure washer to clean the intercooler

Using the pressure washer to clean the intercooler is a good idea. Make sure to follow the operating instructions on the pressure washer, and ensure that don’t hold the nozzle too close to the intercooler.

After removing the intercooler, use the pressure washer to clean the intercooler and the entire pipe. You will be able to clean the intercooler in a few minutes.

5.     Use a vacuum to pick up the debris

Sometimes removing the intercooler is not possible. You may have to just pick up the debris. For example, when removing the intercooler, wear gloves and eye protection. When vacuuming the intercooler, you may use a special attachment to pick up the oil in the intercooler.

If you remove the intercooler, make sure you remove the entire pipe, then vacuum the whole pipe; if this is not possible, use cleaning fluid to clean the intercooler.

6.     Remove and clean the oil drain access holes

There are multiple different reasons to remove the drain access hole. The drain holes will be there to remove the water or any dirt which is traveling inside the engine. You will find your intercooler clogged with oil and debris if there are no drainage holes.

You will also find debris once you open up the pipe as well. This is a good time to clean the intercooler. This is because there is more oil in the intercooler after the cleaning.

7.     Look for any issue with the pipe

You must check the pipe before you start removing the intercooler. There may be several problems with the pipe. There may be clogging, but you will find this easier when you start removing the intercooler.

There may be something else wrong with the pipe that you will need to determine. Once you have determined the problem with the pipe, then you can use the pipe.

8.     Replace the pipe

If the intercooler pipe is worn and old, you will have to replace your pipe. The problem with the old pipe is that it will be contaminated and have rust in it. You may need to replace the pipe if it was punctured or broken.


Depending on the severity of the damage, it may be time to replace the intercooler. If the intercooler is damaged, there is still a chance you can use the intercooler. You will have to replace it immediately if it is severely damaged.

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About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!

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