The Head Gasket is a critical component of a car. It lies between the engine block and cylinder head(s) of a car’s internal combustion engine. It is the most critical sealing application of an engine; which is why a ‘blown head gasket’ can be catastrophic news. Head gasket problems – like a head gasket leak, are just one of the signs of a cracked head gasket.
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What is a Blown Head Gasket?
“Blown head gasket” is a common phrase out of car culture, that has become part of our everyday terminology. Albeit, it’s an expensive fix, unless you know a thing or two about sealers, which we’ll come to in a bit. First, let’s take a look at how you can determine if the head gasket has indeed blown.
Why Do Head Gaskets Blow?
Once you’ve determined your car’s head gasket has blown, either you’ll have to spend money to have it fixed (or replaced), or you can do the repairs yourself. Either method will cost you money. However, a do-it-yourself approach will save you the cost of labor. Prior to heading on to repair it, it’s important to know the cause. There can be a number of possible causes for a blown head gasket. Let’s take a look at each in turn.
An overheated engine is the biggest cause of a blown head gasket. The engine’s parts are made of metal; overheating will cause the metal body of the engine to expand, resulting in a blown head gasket.
Due to the overheating, the head gasket armor around the cylinders becomes crushed. As a result, the seal is lost, the engine loses compression, coolant leaks, and eventually, the gasket erodes.
Installation errors can also cause head gasket failure. In particular, head bolts need to be tightened in the correct sequence and set to the proper torque. Also, the bolts should have clean threads that aren’t stretched or damaged. The engine block and cylinder head surfaces should also be clean, smooth, and flat.
Pre-ignition Problems of an Engine
Pre-ignition problems of an engine put extra strain on the valves and therefore the head gasket. With Pre-ignition or detonation, there is a hot spot in the chamber, causing the ignition of the fuel before the spark plug has a chance to fire. Abnormal combustion due to pre-ignition causes carbon deposits to build up; eroding and blowing the head gasket.
Poor Head Gasket Design & Material
A poorly designed head gasket can cause head gasket problems over time. It is recommended to replace such head gaskets with a proper one. In terms of material, an aluminum head gasket has a higher chance of blowing due to a high thermal expansion rate of aluminum. Iron, therefore, is a better choice, as it has a lower thermal expansion rate.
Knowing the symptoms of a blown head gasket is critical in preventing major car troubles. Let’s take a look at the signs to look out for.
How to tell if a head gasket is blown?
There are a handful of symptoms that can indicate a car has a blown head gasket. These symptoms fall between two categories; the obvious, and the relatively subtle.
What are the Blown Head Gasket Symptoms?
Most of a ‘Head Gasket’ can’t be visually diagnosed without disassembling the engine. Thus, a blown head gasket’s symptoms are difficult to see. However, there are several signs of a blown head gasket that you can search for.
1. External Oil or Coolant Leak
A head gasket will leak coolant if it’s damaged or faulty. As a result, the coolant level indicator will be at the low mark. Regularly checking the coolant level is crucial. Checking for pools of coolant beneath your parked car (below the exhaust manifold) would be another recommended step. A mere visual inspection can fail you in detecting a leak, so it’s important to also look for bubbles in your radiator.
External Oil Leaks are one of the more obvious signs of a blown head gasket. It happens when a head gasket is damaged or faulty and fails to serve its sole purpose.
Also, a head gasket will leak coolant if it’s damaged or faulty. As a result, the coolant level indicator will be at the low mark. To confirm this, it’s recommended you regularly check the coolant level. At this point, checking for pools of coolant beneath your parked car (below the exhaust manifold) would be another recommended step. Keep in mind, a mere visual inspection can fail you in detecting a leak, so it’s important to also look for bubbles in your radiator.
2. Misfire on startup & Light-colored smoke
When starting your car, if you experience a misfire and a puff of white exhaust smoke, it’s likely the head gasket has blown. The damaged head gasket has caused coolant to leak into the combustion chamber, resulting in white smoke coming out of the exhaust pipe.
3. Overheating (Abnormally high Engine Temperature)
Overheating is a less-obvious sign of a blown head gasket. In severe cases, a major leak would have caused bubbles in the overflow tank, tantamounting to overheating.
When the head gasket is blown, your car will usually overheat, especially after a long drive. This is a result of the diminishing coolant (used up by the engine), and the inability of your vehicle’s radiator to cool the contaminated coolant. An overheated engine is an invitation for problems like an expansion of metal components, causing cracks and; and seals and gaskets to get damaged and causing other leaks in your engine.
A Blown head gasket cannot be ruled out as the issue when the thermostat (on the dashboard) indicates an abnormally high engine temperature along with the warning sign being on.
4. Discolored (Contaminated) Fluids
Another more subtle symptom of a blown head gasket is – discolored fluids. Coolant can be contaminated with engine oil, and vice versa. Coolant-contaminated oil is frothy; it’s like a milk-chocolate-like color, much like a latte coffee, under your oil cap or in the valve covers. This happens when coolant seeps into the engine and mixes with the engine oil. Signs of this can also be observed from the engine oil dipstick, or if there’s white smoke coming out from your exhaust pipe.
On the other hand, an oil-contaminated coolant forms a mayonnaise-like film, observed on the radiator cap or in the overflow reservoir. Yet, another symptom of a blown head gasket.
Contaminated fluids (discolored fluids) are another symptom of a blown head gasket. An oil-contaminated coolant forms a mayonnaise-like film, observed on the radiator cap or in the overflow reservoir. Yet, another symptom of a blown head gasket. On the other hand, coolant can be contaminated with engine oil. Coolant-contaminated oil is frothy; it’s like a milk-chocolate-like color, much like a latte coffee, under your oil cap or in the valve covers.
This happens when coolant seeps into the engine and mixes with the engine oil. Signs of this can also be observed from the engine oil dipstick, or if there’s white smoke coming out from your exhaust pipe.
5. Poor Engine Performance
Do you feel your engine performance has been deteriorating? If yes, this might be another symptom of a blown head gasket. Signs of poorly performing engines include: being slow, being unresponsive, having loss of compression, and overheating.
6. Excessive Pressure
Does your radiator cap blow off due to excessive pressure? This could be because of a blasted head gasket. Such excessive pressure can end up cracking your radiator tank or blow a radiator hose.
The above are some of the main symptoms of a blown-out head gasket you should watch out for.
7. White smoke from the Exhaust Manifold
When starting your car, if you experience a misfire and a puff of white exhaust smoke, it’s likely the head gasket has blown. The damaged head gasket has caused coolant to leak into the combustion chamber, resulting in white smoke coming out of the exhaust pipe. This is an outcome of the coolant burning and evaporating with the combustion process and emitting out white smoke from the tailpipe.
What Causes a Blown Head Gasket?
Knowing from the above symptoms, we can conclude what causes the head gasket to blow. The extreme engine temperature is the primary cause. All the mentioned symptoms are somewhat interlinked – the engine heats up when there is a coolant leak or deficient coolant in the radiator.
Interestingly, not all head gaskets will fail at the same rate. The material composition and manufacturing process of the respective car makers plays another key role. You can’t compare a luxury car with a basic one, can you? similarly, you can’t compare one head gasket with another. Thus, different head gaskets will fail at different stages and temperatures.
We can cite aluminum (a material used for some head gaskets) as an example. Aluminum has a relatively high thermal expansion rate. The material weakens and disintegrates relatively faster when the heat is applied. Thus, an aluminum head gasket makes for a sub-optimal choice.
How to Fix a Blown Head Gasket Without Replacing it?
Replacing a head gasket is a long and perplexing task. So much so that you could end up doing more damage than good. Imagine having to separate the cylinder head from the cylinders to get to the gasket. A task requiring onwards of 6-10 hours. Further complicating matters, the airbox, alternator, and compressor would also have to be uninstalled. Unprofessionally handling any of these parts can have catastrophic results.
That’s why the best strategy is to repair the head gasket by using a head gasket leak sealer. The best sealer products are just a click away and can be ordered online. Your worry of disassembling and reassembling complicated car parts ends here.
Read More:- Best Head Gasket Sealers Of 2023
Blown Head Gasket Repair Cost
Replacing a head gasket can be very expensive. To avoid high repair costs, one must correctly identify blown head gasket symptoms. A head gasket replacement can cost anywhere between $1500 to $2000+, depending on the following factors specific to your car’s engine:
- Number of cylinder banks
- Overhead cam VS pushrod engines
- Head or block damage
- Other components replaced
It’s a highly labor-intensive process, whereby the average mechanic charges anywhere from $30 to $65+ per hour. In fact, most of the blown head gasket cost of replacement (70%) can be attributed to labor alone; it takes 10+ hours to do the job.
The good news is, a blown head gasket can be repaired with a sealer. More often than not, it’s worth it to apply a good head gasket sealer to prolong the life and performance of your car. The top sealers available in the marketplace, when applied properly, will seek out and fill the head gasket cracks effectively. This quick-fix comes at an affordable cost and an easy do-it-yourself process.
Is it Possible to Drive with a Blown Head Gasket?
If you’ve got a blown head gasket with multiple symptoms to show just that, it becomes critical that, you drive your vehicle as little as necessary. Hot gases and cold coolant moving through the cracks of the gasket erode or warp the metal head or engine block.
How to Avoid a Head Gasket Failure?
Here are some of the ways in which you can keep head gasket failure at bay:
1. Keep combustion chamber pressures at a minimum (if turbocharged then set back to factory setting).
2. Make sure your engine doesn’t have any pre-ignition or knocking from advanced timing or carbon build-up.
3. Maintain low engine RPMs to reduce stress and heat on your head gasket.
4. In case it’s a manual transmission car, reduce pressure on your head gasket by avoiding downshifting to slow the car.
Can I use a Head Gasket Sealer to fix the Blown Head Gasket?
A head gasket sealer (gasket sealer) is the do-it-yourself method to effectively fix the blown head gasket. Products available in the market come in the form of a paste, glue, or spray. The best head gasket sealers can cost you as low as $15.
The best sealers available in the market effectively combat fluid leakages, plug cracks, and prevent car parts from rubbing against each other. The sealer starts to do its job once you pour it into the radiator and then run your engine for about 35 minutes. The sealer is highly recommended; if your car is old. You wouldn’t want to spend a fortune on replacing a part when an economical quick fix is available as a viable option.
A careful diagnosis to confirm a head gasket is blown can be made by being vigilant with the outlined symptoms. Otherwise, dismantling the engine would not only be a costly affair but removing so many delicate parts can prove to be catastrophic; especially, if the head gasket is not at fault. The more the symptoms, the less advisable it is to drive your car, especially for long drives.
Fixing the problem is recommended before things get worse. Replacement should be the last resort option since it’s quite costly and labor-intensive. Thorough research of the best head gasket sealers can do the trick much to your satisfaction.