What are the Signs of Blown Head Gasket?

An engine is a major part of the vehicle. The proper operation of the engine is very important for the proper working of the vehicle. The head gasket ensures the proper operation of the engine. It prevents the coolant from leaking into the engine cylinder. If your engine head gasket is failed or damaged, it may cause engine failure. This article deeply explains the causes and symptoms of a blown or bad head gasket. 

What is a head gasket?

A head gasket is a part of an engine that separates the engine block and cylinder head. It acts as a seal between the block and cylinder head to stop the leakage of the coolant. It also helps to stop the oil from leaking into the cylinder and stops oil from mixing with the coolant. 

The main advantage of the head gasket is that if your vehicle cylinder head or engine block has any problem, the gasket allows the technician to separate and repair these two major parts of the engine individually.

What is the function of the Head Gasket?

A vehicle engine consists of two parts:

  1. Cylinder block: The cylinder block contains the coolant passages, cylinder sleeves, cylinder, and piston. It is known as the heart of the engine.
  2. Cylinder head: It contains a spark plug, camshafts, and valves.

The main function of the head gasket is to separate the cylinder head and cylinder block and ensure proper circulation of the coolant and oil. It stops the coolant leakage into the cylinder.

The head gasket has the ability to bear extreme pressure and temperature. It seals the internal pressure of the cylinder, coolant, and engine oil flowing through the casting port.  

Symptoms of a Blown Cylinder Head Gasket 

The head gasket is a major part of the engine. It prevents the engine from overheating issues. As your gasket blows, it starts showing different signs. As you identify the signs of a bad or blown head gasket, immediately replace or repair it.

Head gasket leak symptoms

Following are the major symptoms of a blown head gasket:

  1. Oil and Coolant Mixture
  2. White Smoke from the Exhaust Pipe
  3. Engine Overheating
  4. Loss of Power
  5. External Oil/Coolant Leaks
  6. Milky Coolant
  7. Low Coolant Level
  8. Bubbling In Cooling System
  9. Misfiring

1) Oil and Coolant Mixture

As we discussed earlier, the function of the gasket is to prevent the mixing of the oil and coolant. If your engine head gasket is severely blown or damaged, engine oil and coolant can mix together. This may generate many problems for your engine.

The car engine coolant and oil can mix due to various reasons, but they may also mix due to a bad head gasket. As you notice this symptom, immediately inspect your gasket and replace it if it is damaged or blown.

2) White Smoke from the Exhaust Pipe

A major symptom of a blown head gasket is that your vehicle starts emitting white smoke from the tailpipe.

As your gasket is blown, the coolant starts leaking into the engine cylinder, where it mixes with oil and starts burning. As your coolant burns, your engine produces visible white smoke that you can see from the tailpipe of your vehicle.  

3) Engine Overheating

The engine overheating may cause due to a bad head gasket.

The head gasket ensures the proper circulation of the coolant and engine oil throughout the system. As your gasket is damaged or blown, the coolant can’t circulate properly throughout the system. It may lead to an insufficient supply of the coolant due to that engine doesn’t cool properly. This issue leads to engine overheating.   

4) Loss of Power

The head gasket seals the internal pressure and temperature of the cylinder and prevents them from leaking. As the engine gasket damages or blows, the internal pressure of the cylinder may leak due to that engine will need to work harder to achieve the desired output. In this case, you can also observe a reduction in engine power.  

5) External Oil/Coolant Leaks

In some cases, you can observe a visible oil or coolant leak due to a blown head gasket. This leak occurs from the mating point between the cylinder head and engine block.

6) Milky Coolant

One of the major symptoms of a blown head gasket is the build-up of milky sludge on the internal side of the oil filler cap or on the dipstick, sometimes jokingly called a “milkshake .”This causes due to mixing of coolant with the oil. 

Although this milky sludge may also build-up due to some other reasons but most commonly, it causes due to a blown head gasket.

7) Low Coolant Level

If your car is consuming more coolant than usual, then you can see a quick reduction in your coolant level. This quick reduction in the coolant level is a sign of a damaged head gasket.  

As we know, the head gasket installs inside the engine. Therefore, in case of a head gasket leak, the coolant often burns without visibly draining.

8) Bubbling In Cooling System

The slow and steady blowing of coolant in a vehicle’s radiator or expansion tank is usually a sign of insufficient combustion gas. A specialized combustion gas detector may use to confirm this issue.

9) Misfiring

If your car engine is misfiring, it means that your car head gasket has been leaked. This misfiring occurs due to coolant burning in the combustion chamber.

What causes a head gasket to fail?

1) Engine Overheating

As your car engine overheats, it generates many problems. It may overheat due to different reasons. The engine overheating may cause a blown head gasket. If the engine temperature exceeds the bearable gasket limit, your head gasket will be blown. Overheating may also warp or crack the engine block or cylinder head and prevent the head gasket from sealing properly.

Solution: Most commonly, the engine overheats due to a bad cooling system and low coolant level. Properly inspect and maintain your vehicle’s cooling system and prevent your engine from overheating.

2) Pre-ignition and Knocking

The pre-ignition process takes place just before the spark plug fire, and knocking takes place after the spark plug fire.

Knocking and pre-ignition are one of the most common causes of a blown or leaking head gasket. These conditions lead to high pressures and temperatures inside the cylinder, which can put severe stress on the gaskets.

Solution: Properly Inspect your vehicle engine and prevent it from knocking and pre-ignition issues.

3) Unexpected temperature changes

The engine temperature plays a big role in the contraction and expansion of the gasket. If you start an engine cold and instantly put your foot down, this sudden temperature changes can cause head gasket failure.

Solution: Allow the car engine to reach up to a specific operating temperature before sudden acceleration can avoid head gasket failure.

4) High mileage

The high mileage of your vehicle can also lead to a blown head gasket. Your manufacturer manual suggests the replacement of the gasket as the car covers a specific mileage point.

Solution: Replace your head gasket after the manufacturer’s prescribed mileage point.

5) Head Gasket Age

The age of the gasket may also cause gasket failure. You must change the gasket according to the prescribed age on the manufacturer manual.

6) Incorrect installation

If you replace the gasket incorrectly, it cannot stay tight for an extended period. If you replace the head gasket and the problem occurs immediately after the repair, there may be a problem with the installation.

7) Low Coolant Level

The low coolant level leads to engine overheating issues. As the engine overheats, it causes gasket failure. In this way, the low coolant level leads to gasket failure.

Solution: Inspect the coolant level before driving the vehicle and fill it if it is lower than the required level.

How to Prevent Head Gasket Failure

One of the best methods to prevent head gasket failure is proper inspection and maintenance of the engine cooling system. The inspection and maintenance of the cooling system include:

  1. Sufficient coolant level
  2. Proper working of the water pump
  3. Proper working of the radiator
  4. Proper working of heater core hoses
  5. Inspection and replacement of the thermostat housing seals.

As you observe a problem in any unit of your cooling system, immediately contact a technician and ask to fix the problem.

FAQ Section

Can I drive with a blown head gasket?

You shouldn’t drive your vehicle in case of a bad or failed head gasket. In this case, your vehicle may lose control, and it may cause a severe accident.  

What are the signs of a blown head gasket or cracked head

Following are the signs of a blown head gasket:

  1. Misfiring
  2. Oil and Coolant Mixture
  3. Bubbling In Cooling System
  4. Low Coolant Level
  5. White Smoke from the Exhaust Pipe
  6. Engine Overheating
  7. Milky Coolant
  8. Loss of Power
  9. External Oil/Coolant Leaks

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