Oil is necessary to maintain the smooth functioning of internal combustion engines. Meanwhile, coolant regulates the engine temperature. Oil is directly added to the engine to lubricate different components and reduce friction, whereas coolant is added to the coolant reservoir and helps maintain optimum temperature.
Due to varied functions, both fluids have different channels to travel around the engine. That said, when the coolant and oil mix, it can cause significant damage to the engine.
Let’s understand the common reasons behind the mixing of coolant and oil in cars and the symptoms in case it happens.
Why Engine Oil Mix with Coolant
Engine cooling systems are used in internal combustion (IC) engine cars to cool down excessive heat generated during combustion. Engine coolers use fluid, which can be either coolant or water, to maintain the optimum temperature of the engine. Regardless of the fluid you are using, its mixture with oil indicates malfunctioning auto parts.
Let’s take a closer look at the auto parts whose malfunction leads to coolant and oil mix in cars.
Faulty Head Gasket
The head gasket is one of the most essential parts of the internal combustion engine. It is used to seal the combustion chamber to prevent pressure leakage. Moreover, it ensures that oil is not leaking from the chamber and mixing with coolant. That said, even the slightest crack in the gasket leads towards oil and coolant mixing in cars.
The only solution to this problem is to replace the blown head gasket. For immediate remedy, you can use the head gasket sealer available in the market. Drain the oil pan and coolant reservoir using a sealer. Then, mix the sealer with the new coolant and add it to the reservoir. Remember that it is just a temporary solution and its effectiveness is not guaranteed.
Leaking Oil Cooler
The oil cooler is a part of the engine cooling system and is located in the front of the car under the main radiator. Its purpose is to reduce the temperature of hot oil coming directly from the engine. The oil passes through the coil and the coolant is present in the cavity around the coil sealed by the cooler. Therefore, any leakage or crack in the coil of the cooler leads to oil and coolant mixing.
You can fix this issue by replacing the oil cooler at home. Drain the coolant completely from the oil cooler and dry it for a few minutes. Now, unscrew the faulty cooler and replace it with a new one.
Cracked Cylinder Head
The cylinder head is a part of the combustion chamber that is responsible for controlling airflow and fuel deployment. It has the greatest number of moving parts than any other engine component. Therefore, it requires oil to reduce friction. Cylinder heads are durable but excessive heat and friction can result in cracked cylinder heads leaking oil into the coolant.
Modern cars are equipped with an aluminium cylinder head that is irreparable and the only solution is to replace it with a new one.
Damaged Engine Block
The engine block is the main structure of a combustion engine that contains cylinders and other components. Any damage to the engine block can cause severe oil leakage and mix with coolant. A damaged engine block is not a frequent problem and will occur rarely.
However, If you face this issue, the only solution is to replace the engine block which can cost you a fortune.
Therefore, it is suggested to purchase another car rather than spend on the repair of an old one. You can browse through these used cars for sale in the UAE and find a second-hand car as per your budget.
Seeping Transmission Cooler
Transmission coolers are used in vehicles offered with an automatic transmission system. Their role is to reduce the temperature of hot hydraulic fluid coming from the transmission system. A leaking or damaged transmission cooler leads to a coolant and oil mix that causes irreparable damage to the transmission system.
How to Know If Coolant Is Mixing with Oil
Mentioned below are the symptoms of coolant and oil mix in cars.
Overheating
A mixture of oil and coolant disrupts the chemical composition of both fluids- reducing their effectiveness. That said, a lack of lubrication will increase friction and result in an overheated engine.
Exhaust Smoke
A cracked cylinder head or gasket can be identified by the excessive amount of white smoke coming out from the exhaust. Generally, the smoke has a sweet smell that will also be present inside the car cabin.
Dipstick
When oil mixes with coolant it forms a milky liquid that can be seen on the dipstick. For more information, read our blog on how to read a dipstick.
Reduced Coolant Level
When coolant is leaking or mixed with oil the coolant level in the reservoir will drop rapidly. Monitor the coolant level in the reservoir on a weekly basis and consult a mechanic in case of any abnormal drop.
FAQs
How to know if coolant is mixing with the oil?
Multiple symptoms indicate coolant mixing with the oil. Common ones are a drop in coolant level, a milky mixture on the dipstick, excessive smoke from exhaust and a sweet smell in the car cabin.
Why do oil and coolant mix in the engine?
Coolant and oil mix can occur due to malfunctioning auto parts. It is mainly because of a damaged head gasket, cylinder head and leaking oil cooler.
What happens when coolant is mixed with oil?
The mixture of coolant and oil reduces the efficiency of both fluids. This results in more friction and heat causing severe overheating and wear and tear to the engine.
These were all the symptoms and causes of coolant and oil mix in cars. Oil and coolant mixture indicates major malfunctioning in vehicles and the majority of the auto parts involved are irreparable. Therefore, the recommended solution is to purchase another car, rather than spend a fortune on the repair of the old one.
If you are considering buying a used car, here is the list of everything you should check before buying a used car in the UAE.
However, if you are planning to purchase a new one, read our blog on things to know when buying a new car in the UAE.
Stay tuned to UAE’s leading auto blog for more information on the consequences of water coolant mixing with oil.
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