Blown Head Gasket – 7 Main Symptoms!

Blown Head Gasket – 7 Main Symptoms!

February 8, 2024 0 By CarGuy

Are you having a problem with a blown head gasket and you are looking to find out more on how you can tackle this problem? If that’s correct, you are in the right place because, in this article, there will be a lot to cover on the topic.

Doing good and thorough research is always a good idea, you just don’t want to rely on mechanics. Good research will give you a very strong input on the problem and the methods of how this problem can be tackled.

This is why we are doing a full guide on how you can repair a blown head gasket. First, we will cover the basics and then we will discuss the blown head gasket symptoms. After that, we will cover the blown head gasket repair cost. So, without further ado, let’s dive into the article!

What Is A Head Gasket?

Before we delve into more complex topics when it comes to a blown head gasket, let’s first learn more about the basics and see what this component is and why it is so important.

Every engine has at least one deck. An engine deck is the top portion of the block. The part of the block that is perfectly machined and where you can see the individual cylinders.

Directly on top of the deck of the block, the cylinder head is mounted. The cylinder head is the piece that holds the valves, camshafts, as well as injectors, and spark plugs.

So, the deck of the block and the cylinder head are mated together and are held by the head bolts.

Here is where the head gasket comes into play. This gasket material is placed between the deck of the block and the cylinder head and helps keep a good seal.

This is really important because if there is no gasket material to keep a good seal, the engine will consume coolant, and there will be oil leaks and low compression. This is why the head gasket plays such a vital role in the engine.

These symptoms can also appear when the gasket is blown and you have a blown head gasket situation. But more on the symptoms we will elaborate later.

The important thing about head gaskets is that they are not your typical paper gaskets. But these gaskets are made from steel. Usually a few sheets of very thin steel or copper in some cases.

Overall, these are the most important things to know when it comes to head gaskets and their function.

Blown Head Gasket Symptoms

Now let’s discuss the blown head gasket symptoms, or the signs of a blown head gasket since they are all pretty much the same.

What is interesting about this gasket is that the gasket can fail in different ways and cause different symptoms. So, let’s cover all of these symptoms in detail and learn more about them.

1. Milky Engine Oil

One of the most common symptoms associated with a blown head gasket is a milky residue on the oil cap and in the engine oil. This problem happens when the gasket fails and the oil and coolant come into contact. And the coolant enters the oil compartment.

What many people don’t take into consideration is that sometimes the milky residue on the oil cap can often be because of condensation. So, this is not a real clue that the gasket has failed.

The most probable symptom is the case when you have a milky oil. Usually, when this problem happens, the oil will be thicker and light brown in color. Something like a milkshake substance.

In this situation, you really have a blown head gasket and this problem has to be addressed as soon as possible.

2. White Smoke From Exhaust

The second symptom of a blown head gasket is white smoke from the exhaust. This symptom occurs when the gasket fails around the combustion chamber.

When this happens, the coolant will fall into the combustion chamber and will burn. When coolant burns or evaporates, it leaves white smoke.

Cars that burn serious amounts of coolant, will leave a cloud of white smoke from the tailpipe.

Whenever you have white smoke, you should address this problem as soon as possible because in 99% of the cases means that you have a blown head gasket.

3. Overheating Problems

The next symptom is fairly common when you have a blown head gasket. We are talking here about overheating.

Usually, in 99% of the cases, the head gasket fails precisely because of an overheating issue. There can be many reasons for overheating.

For example, if the engine was overloaded, if there was a low coolant level, bad water pump, and bad thermostat.

All of these issues can lead to engine overheating and whenever the engine overheats, the head gasket will fail since it is the weakest point.

The car will continue to overheat if the gasket fails because you need to fix the culprit for the problem as well.

So, it is a smart thing to monitor the temperatures and make sure that the car is running normally. Since if you don’t the car will overheat too seriously and the damage will not be fixable.

4. Low Coolant Level

Another very common symptom associated with a blown head gasket is the low coolant level. This is a common thing because the coolant will simply disappear.

In many cases, you will not be able to track where the coolant goes because this coolant will end up in the oil compartment, leak from the sides of the engine, or burn in the combustion engine.

This is why if you have coolant loss with no visible leaks anywhere around the engine, the engine is highly likely to burn the coolant.

5. Bubbling In The Expansion Tank

Bubbling is also a common thing on cars that have a blown head gasket. This bubbling appears in modern cars in the expansion tank and in older cars in the radiator.

So, what are these bubbles, and what is creating them? Well, this is simply air that is running through the system and ends up in the coolant expansion tank. The air is created because of the blown head gasket.

The expansion tank has a valve to release the pressure. But sometimes the pressure can become so much that it can simply cause the expansion tank to explode.

An important thing to note is to never touch the expansion tank while the car is hot. The coolant is basically boiling inside and can burn your skin if you by accident open up the cap.

6. External Leaks

External leaks are also common and can cause unexplainable loss of coolant. This often occurs when the gasket fails on the sides of the block.

These failures are somewhat less common thing compared to the other failures of the gasket. But they can occur sometimes.

Usually, when the gasket fails on the side, there will be white stains on the engine block. These stains are left once the coolant evaporates. Which is pretty immediate since the engine block is very hot.

7. Poor Engine Performance

The last symptom of a blown head gasket is poor engine performance. This is a very common thing on engines that have a failed head gasket.

Mainly the problem is because there is a loss of compression and overheating. The engine simply doesn’t enjoy this situation and will run pretty poorly. It can stall or be seriously down on power.

Blown Head Gasket Repair Cost

The repair cost for a blown head gasket is not cheap, it usually costs between $1,000 and $2,000. The part itself is really cheap but replacing it is rather expensive.

This is because of the labor. Usually whenever an engine has a blown head gasket, the cylinder head will get warped.

In this situation, the cylinder head has to be machined in order to make it even, so the gasket can be applied.

This is a process that takes a very long time to do. You need to have the right equipment and skill set to complete this job. All this increases the blown head gasket cost to fix.


Overall, a blown head gasket is something that you don’t really want to happen but it can happen quite unpredictably.

The important thing is that you make sure that you monitor the temperatures if you want to avoid this problem from occurring.

And even if it occurs, make sure that you fix the problem immediately because the more you run the engine, the worse it will overheat and it will be more expensive to fix.

If you want to read more, you an check our article on the head gasket symptoms.


What causes a blown head gasket?

A head gasket can fail from engine overloading or overheating. Usually, when the engine is pushed too hard, the gasket is one of the weakest points that often fails first.

How to tell if head gasket is blown?

A blown head gasket can trigger various symptoms. These include coolant loss, bubbles in the expansion tank, milky engine oil, engine overheating, white smoke from the exhaust, and poor engine work.

What are the first signs of a blown head gasket?

This depends on how the gasket has failed. But overall, the engine will run poorly because there will be not enough compression in one of the cylinders. It can overheat and produce white smoke from the exhaust.

How much to fix a blown head gasket?

Fixing a head gasket is rather expensive. This job can cost between $1,00 to $2,000 on average depending on the hours of labor involved in it.