An internal combustion engine contains several fluids and components which work together to make your car run smoothly and get you from point A to point B.
The head gasket is a seal between the engine block and cylinder heads. It prevents different fluids from mixing, which is critical for the engine to work as intended.
When there is a leak in the head gasket, many people, including mechanics, usually refer to it as a “blown head gasket”. There are three types of fluids that are prevented from mixing by the head gasket.
Those fluids are oil, coolant, and the air/fuel mixture in the combustion chamber. If any of these fluids mix with one another, they will cause problems in their associated systems.
Let’s take a look at the symptoms first!
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Symptoms Of A Blown Head Gasket
There are several telltale signs that could appear when there is a leak in the head gasket.
These symptoms include:
- White smoke from the exhaust
- Engine overheating
- Milky-colored oil
- Engine knock
These symptoms all occur due to the mixing of the different fluids. However, even if the head gasket is blown, it does not necessarily mean that all the fluids will mix.
Nor does it mean that all these symptoms will necessarily occur in the event of a blown head gasket. If you notice these symptoms, you should turn off your engine as soon as possible and hire a mechanic to take a look at your car.
White Smoke From The Exhaust
In most cases, white smoke from the exhaust means there is something in the combustion chamber or the exhaust that should not be there.
If the white smoke is being caused by a blown head gasket, this is because of oil or coolant entering the combustion chamber.
There are several reasons why white smoke may appear. It doesn’t always indicate a serious issue, but you should pay attention to it and try to discover the cause.
Engine overheating is the most common symptom of a blown head gasket.
As the coolant leaks into the combustion chamber, it evaporates and is expelled from the exhaust. As a result, the coolant is quickly depleted.
As there is no coolant available, this causes the engine to overheat. Lack of coolant isn’t the only reason this might occur; a blown head gasket will also result in less efficient power generation, producing more heat.
The engine oil plays an important role by lubricating many crucial parts in the engine compartment. Oil and water are not designed to go together; if they do mix, it will result in a milky-colored frothy liquid.
This unwanted cocktail of oil and coolant will mean the lubrication properties of the engine oil become almost non-existent.
If you suspect a blown head gasket, you can check the oil filler cap to see if there is any milky-colored and frothy liquid. If it is present, a blown head gasket is a likely culprit.
It is important to mention that oil and coolant can also mix if there is a problem elsewhere, so this issue is not exclusively caused by a blown head gasket.
The oil that leaks into the coolant system will produce a mayonnaise-like film which might be seen in radiator caps. Bubbles may also be visible in the overflow tank.
Another complication caused by coolant leaking into the combustion chamber is hydrolocking the engine.
In more serious cases, the engine will lose a substantial amount of compression which causes engine knocking.
You will also notice a rough idle when standing still. In some cases, the engine might even stall. This is due to friction between non-lubricated moving parts, which can cause permanent damage.
As with the other symptoms described, a rough idle and engine knock are not exclusive to a blown head gasket, but they are often signs of one.
Repair Cost Of A Blown Head Gasket
Unfortunately, a head gasket repair is one of the most expensive car repairs. This isn’t because of the head gasket itself, but its position in the engine compartment.
Because of its central location, the engine has to be disassembled. This can take many hours, which in turn means that the repair is very labor-intensive.
The job is not one for an inexperienced mechanic, nor an average one. Because of this, we recommend taking your car to a professional if you suspect it has a blown head gasket.
On average, a new head gasket will cost you $100 to $200, depending on the car model. The most significant expense, as mentioned previously, is the labor cost.
This labor cost will vary dramatically depending on the car model and other factors. As a general guide, you should expect to pay between $900 to $1500 in labor costs.
Some people swear by using head gasket sealers while others strongly advise against them. In truth, there is no universal answer. In rare cases, it might work, but a full repair will usually need to be done.
The role of the head gasket is to prevent fluids from mixing between the engine block and cylinder heads. These fluids are usually oil, coolant, and air/fuel mixture from the combustion chamber.
A leak in the head gasket is the same as a “blown head gasket”. The most common cause of a blown head gasket is engine overheating.
This means it is important to always ensure that the coolant is at an acceptable level.
The mixture can be problematic in both ways. For example, oil can leak into the coolant system, and coolant can leak into the lubrication system. In many cases, the oil and coolant leak into the combustion chamber.
The most common symptom is engine overheating. However, other symptoms such as white smoke from the exhaust, milky-colored frothy oil, and engine knocking are not uncommon.
A head gasket sealer is a cheaper alternative to repairing a blown head gasket. However, this is never a permanent solution and, in the majority of cases, it won’t work at all.
Replacing a head gasket is one of the most expensive car repairs due to the high labor costs involved. This is because the head gasket is located between the engine block and the cylinder heads.
If you need to replace a head gasket, it will cost you on average $100 to $200. However, the labor cost might be ten times that, if not more.
As a general rule, you can expect to pay $900 to $1500 in labor costs alone.
You should also keep in mind that a blown head gasket could result in damage to other components. This means the repair bill might end up much higher.