The internal combustion engine consists of several fluids and components which together make your car run smoothly and take you from place A to place B.
The head gasket is a seal between the engine block and cylinder heads. It prevents different fluids mixing which is critical for the engine to work properly.
When there is a leak in the head gasket, most people and mechanics refer to it as a “blown head gasket”. In short, three types of fluids are prevented to mix by the head gasket.
The fluids in question are oil, coolant, and the air/fuel mixture in the combustion chamber. If any of these fluids mix, they will cause problems in both the systems the fluids are affiliated with.
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Symptoms Of A Blown Head Gasket
Many symptoms may occur when there is a leak in the head gasket. Symptoms that may show include:
- White smoke from the exhaust
- Engine overheating
- Milky-colored oil
- Engine knock
All these symptoms occur due to the mixing of the fluids. If the head gasket is blown it does not necessarily mean that all the fluids will mix.
Likewise, it does not mean that all these symptoms will occur. If you do notice these symptoms, you should turn off your engine as soon as possible and make sure a mechanic takes a look at it.
White Smoke From The Exhaust
White smoke from the exhaust in most cases means that there is something in the combustion chamber or the exhaust that should not be there.
When it comes to a blown head gasket, the reason for white smoke appearing from the exhaust is due to oil or coolant entering the combustion chamber.
There are several reasons why white smoke may appear. It is not always disastrous, but you should be cautious if it happens.
Engine overheating is the most common symptom of a blown head gasket.
As the coolant leaks into the combustion chamber where it gets evaporated and expelled through the exhaust, the amount of coolant will deplete fast.
As there is no coolant, it will result in an overheated engine. Not only is the coolant the culprit, but a blown head gasket will also result in ineffective power generation, producing more heat.
The engine oil plays an important role in the lubrication of many crucial parts in the engine compartment. Oil and water are far from best friends, if they do mix, it will result in a milky-colored frothy liquid.
The resulting liquid is from the mixing of oil and coolant and will make the lubrication properties of the engine oil almost non-existent.
If you do suspect a blown head gasket, you may check the oil filler cap to see if you can spot any milky-colored and frothy liquid. If it is present, a blown head gasket might be the culprit.
It is important to note that oil and coolant also may mix if there is another problem elsewhere, meaning that this symptom is not exclusive to a blown head gasket.
Oil that has leaked into the coolant system will produce a mayonnaise-like film which may be seen in radiator caps. Bubbles may also be seen in the overflow tank.
Another complication of coolant leaking into the combustion chamber is hydrolocking the engine.
In more serious cases the engine will lose a substantial amount of compression which will produce engine knocking.
You will then notice a rough idle when standing still, and in some cases, the engine might even stall. This is due to non-lubricated moving parts hitting each other, causing permanent damage.
Just like the other symptoms described, a rough idle and engine knock is not exclusive to a blown head gasket, but it might be a good clue for what is happening.
Repair Cost Of A Blown Head Gasket
Unfortunately, a head gasket repair is one of the most expensive car repairs. The reason is not due to the head gasket, but its central role in the engine compartment.
Because of the location, the engine has to be disassembled which may take many hours, which in turn means that the repair is extremely labor-intensive.
The job is also not for a newbie DIY-er, nor an average one. It is therefore recommended to take your car to a professional if the car has a blown head gasket.
Buying a new head gasket will cost you on average $100 to $200 depending on the car model. The biggest cost, as previously noted is the labor cost.
In this case, the labor cost varies dramatically depending on the car model and other factors. Nevertheless, expect to pay between $900 to $1500 in labor costs.
Some people swear by using head gasket sealer while others strongly advise against the use of them. The truth is somewhere in between, in some cases, it might work but 9 times out of 10, a full repair must be done.
The role of the head gasket is to prevent fluids from mixing between the engine block and cylinder heads. The fluids in question 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 greatest cause for a blown head gasket is engine overheating.
It is important to make sure the coolant level is always on an acceptable level.
The mixture can go 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 while other symptoms such as white smoke from the exhaust, milky-colored frothy oil, and engine knocking are not unusual.
A head gasket sealer is a cheaper “alternative” to fix a blown head gasket, however, this is never a permanent solution, and in most cases, it will not work at all.
Replacing a head gasket is one of the most expensive repairs due to the high labor costs as the head gasket is located between the engine block and the cylinder heads.
In terms of buying a head gasket, it will cost you on average $100 to $200 but the labor cost might be ten times the cost, or even more.
To give an approximation, you can count on paying $900 to $1500 in labor costs alone.
It should also be noted that a blown head gasket may result in further damage to other components, which means that the repair bill may be much higher.