Blown Head Gasket: Signs, Symptoms & Causes

Your vehicle is complicated, intricate machinery that works on very precisely curated and fixed parts and systems. The entire working of a vehicle, though divided into several parts, works in harmony, right from the first twist in the ignition to the rolling of the engine and wheels. The invention keeps us in awe, but with machinery and technology, there is always the scope of something running adrift. In this particular article, we address the issue of the head gasket and how their malfunction can lead to the complete failure of the engine.

A blown head gasket is never good news for the owner. You suddenly see spiralling dollar bills and worry about the magnanimous cost of the repair that will accompany this malfunction. Though it is rare, we do see multiple instances of a blown head gasket, often attributed to poor manufacturing or irregular maintenance. If you’re looking for some more information on the blown head gasket, how to prevent it, and it’s signs and symptoms, the article is addressed to you.

Keep reading on to find more information on head gaskets!

What is a Head Gasket?

The head gasket has a very pressurizing job as it is placed between two very crucial parts of the engine. Every car engine is divided into two parts; the cylinder head and the cylinder block. The Cylinder Head is where all the valves, camshaft(s), and spark plugs are placed whereas the cylinder block is home to pistons and cylinders. The Head Gasket is placed between the head and block, managing the fluids and compression.

The job of the head gasket is to seal the combustion chamber that aids in the build-up of compression, and to keep the coolant and oil away from the combustion chamber. It keeps the oil between the cylinder head and block, allowing it to circulate freely around the engine. Simultaneously, it also does the same with the waterways, such that the coolant can travel wherever needed.

Every modern engine is fitted with a gasket, however, its thickness, construction, and durability are dependent on the skills of the manufacturer. However, unlike the other car component, the head gasket will fail due to wear out when used over its life or due to misuse/neglect.

Now that you know the critical placement and working of the head gasket, you would be better able to understand why every car owner fears a blown head gasket.

Let’s understand better what leads to a blown gasket.

Why do the Head Gasket Blow- The Causes?

We have already seen how a head gasket stands between the two most crucial parts of the engine, regulating them and preventing the liquids from mixing. Such crucial placement entails pressure, which arises from the fact that it has to withstand hot, high-pressure combustion gasses, as well as the cold ambient temperatures of the engine coolant. This can cause a leak in the gasket, leading to the failure of the component. The gasket can also fail when the engine overheats, causing an increase in thermal pressure and an additional strain on the gasket.

When the head gasket fails to perform its tasks, it results in coolant leaks, oil leaks, or gases escaping from the combustion chamber. Moreover, a gasket that is not installed properly or a low-quality one could also lead to malfunctioning of the component.

We know that the gasket is placed between the Cylinder head and block, making it shielded from the general eye view. You would have to disassemble the engine to diagnose the issues with the gasket, which is not always feasible. This makes it very difficult to identify a blown head gasket, which makes it very crucial to know how to identify the signs and symptoms.

Read More: Car Servicing 101: Top Benefits of Regular Car Servicing

Signs and Symptoms of a Blown Head Gasket

1. Leak

One of the biggest signs of anything wrong with the vehicle is when you spot a leak; it is never good news. In the case of a blown head gasket, the coolant leak is spotted below the intake or exhaust manifold. This is only possible when the engine is warmed up.

In case there are no other cooling passages or hose placed near the gasket, you can easily conclude that the leak is due to a blown head gasket. In other instances, you might need to add a UV due to top the coolant and then spot the leak in the head gasket with the help of a UV light.

Any leak coming from anywhere in the car is a telltale sign of something going wrong with the car, and it is always a good idea to have professional hands check them.

2. White Smoke

When the leak is external, you can spot it with the method explained above. However, with the head gasket, most of the leaks are internal when the coolant is allowed to flow into the combustion chamber. When the gasket fails its job to keep the fluids separate, the coolant burns/evaporates with the combustion process resulting in a cloud of white smoke from the tailpipe.

It is most easily recognizable and carries a sweet smell that makes it even more apparent. The magnitude of the leak decides the volume of white cloud that you would witness from the tailpipe. 

3. Blue Fumes

White Smoke indicates a burning coolant, but that’s not the only smoke that identifies a leak. Blue Smoke may also indicate a head gasket failure and burning engine oil. The leak happens when the engine oil escapes from the lubricating pistons and enters the combustion chamber. If you see blue smoke coming from your car, it might be time for a quick inspection.

Since oil doesn’t burn as cleanly as fuel, the smoke is very noticeable. Make sure you don’t continue driving and have the gasket checked urgently.

Read More: Motor Oils: How to Pick the Best Engine Oil for Your Car?

4. Bubbles in Radiator

If the coolant can enter the combustion chamber, an internal head gasket leak may allow exhaust gases into the coolant. This leads to bubbles in the radiator or coolant reservoir, which gives it a look of boiling even when the liquid is cold.

The bubbles are indicative of exhaust gases that are in the cooling system during the combustion process. You can bring your car to the nearest service centre if you spot any bubbles in the radiator. 

5. White/Milky Oil

Another sign of a blown head gasket is spotting the White/milky Oil.

As the coolant leaks into the combustion chamber, it can travel through the piston rings into the oil. As the oil and water mix together, they form a milky white consistency which can be easily spotted with the help of the dipstick around the engine oil cap.

Apart from infiltrating the oil, the mixture of water+oil will lead to inefficient lubrication of the motor, which results in wear on the cylinder walls and the crank and camshaft bearings. It is a good idea to get your vehicle checked when you spot a Milky or White Oil. 

6. Overheating

An overheating engine is one of the most common symptoms of a blown head gasket. A blown head gasket will not be able to prevent the oil from entering the coolant system, which eventually leads to a slowdown in the engine cool off. Furthermore, the inefficient combustion process, the heat from the exhaust, and the issue of dirty coolant in the radiator; all lead to further overheating of the engine.

An overheating engine can cause many issues including expansion of metals, seal damage, leakage, etc. It is important to address the issue and ensure that you never take an overheated engine for granted.

Read More: How to Troubleshoot an Overheating Car?

Now that you understand the working of a Head Gasket and the Symptoms of its malfunctionings, let’s take a look at some Frequently Asked Questions.

FAQs – Frequently Asked Questions

How much does a Head Gasket Repair cost?

There is no one correct answer to this question. The repair cost varies from vehicle to vehicle and is dependent on factors like the Number of cylinder banks, head/block damage, Overhead cam VS pushrod engines, and other replacing components.

Can I drive with a Blown Head Gasket?

It is not recommended to drive with a blown head gasket, especially if you can see some prominent signs and symptoms explained above. If you continue driving with a Blown Head Gasket, the movement of gases and coolant can erode the metal head or engine block, leading to a considerably huge bill.

How Long Do Head Gaskets Last?

Head Gaskets are known to last for 200,000 miles, which is pretty much the lifetime of most cars. Regular maintenance and proper caretaking should never lead to a blown head gasket.

Can You Repair a Head Gasket Yourself?

A DIY procedure is only possible when the issue is very minimal; for instance a small leak. This can be repaired with the help of a sealant. However, when it comes to major issues, it is advisable to drive down to a car repair garage instead of attempting to repair the head gasket yourself.

This brings us to the end of our article on the Blown head gasket and its signs. Hope this was helpful and informative enough to identify any symptoms. For more such articles, keep watching this space.