So, you've discovered that your head gasket is leaking in your car. What to do now? The fact is getting your head gasket fixed by a mechanic is a very costly job. A leaking head gasket may not look like much, in fact a head gasket by itself is a fairly inexpensive piece of technology. You could buy a brand-new head gasket from a site like AutoZone for under $50. Sometimes you can get them for under $20. But having it installed in your car could cost upwards of $1,000 to as much as $2,000 depending on the make and model of your car. That makes something like a head gasket leak sealer a very attractive idea for fixing the problem at a far lower cost.
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Let's take a look at exactly what your head gasket does, what can make it start leaking, and whether or not a head gasket leak sealer is going to fix the problem for you so you can get your car back on the road without spending a ton of money.
What is a Head Gasket?
The head gasket in your car goes between your cylinder head and the cylinder block. As the name implies it's a simple gasket meant to seal your engine and prevent coolant or oil from leaking inside. It also helps control the pressure in your engine which is important for maintaining the precise combustion reaction that you need to get your car moving in the first place.
If you have a faulty head gasket then you can get coolant or oil leaking into the cylinders of your engine. That can lead to poor engine performance as well as your engine overheating since the coolant and the oil is not being sent to where it needs to go.
Back in the day a head gasket was probably made out of something like asbestos or graphite. These were good at handling heat, but they were not particularly durable otherwise. Modern head gaskets will be made of sheets of very thin steel and elastomer pressed together. They can be very durable, but they are still susceptible to failing especially if they're exposed to high heat situations or coolant that has had the pH thrown off because it's badly contaminated.
Over time heat and acid will wear down a head gasket and cause it to blow out on you. That's going to allow the gases to escape from your combustion chamber and contamination of coolant in oil.
When you do blow a head gasket, replacing it is not always the only option available to you. Head gasket sealers do exist which could potentially fix the problem for you and save you a lot of money in the long run if they apply to your particular situation. However, you can't use a head gasket sealer in every situation.
What is a Head Gasket Leak Sealer?
Head gasket leak sealers are products that you can pick up at automotive supply stores, even places like Amazon.com and Walmart, that offer you a much more affordable method of fixing a blown head gasket in a way that won't set you back thousands of dollars. You can typically buy a bottle of gasket sealer on a site like Amazon for probably around $40 to $100. Compared to a $2,000 repair bill from the mechanic you can see why this would be a better option.
They come in liquid form and you pour the product into your radiator to allow it to circulate through your coolant.
How Do You Use a Head Gasket Leak Sealer?
Whatever kind of head gasket leak sealer you buy you always have to follow the instructions on the label exactly. That's going to be your best bet for figuring out how this product is meant to be used. That said, in general they all follow the same basic method.
Once you buy your head gasket sealer you pour it into the radiator. You'll have to let your car run for anywhere from 15 minutes to 30 minutes with your heater and fan on full blast. The chemicals in the sealer will circulate through your coolant system. When they reach the head gasket in your engine, they're going to fill in the cracks that have developed which caused the leak in the first place. Because your car is operating at a high temperature the chemical process will bond to the gasket itself and fill the gaps that are present. After a certain amount of time, which should be detailed on the particular instructions for the product you bought, the chemicals will harden in place and the holes or cracks in your head gasket will be fixed.
Is a Head Gasket Leak Sealer a Permanent Solution?
This is a tougher question to answer than you might think. Technically speaking a head gasket sealer is not really a permanent solution. It's very likely that your head gasket is more prone to blowing out again after you've used a head gasket sealer because it's simply been weakened in some way and whatever happened to it the first time is entirely capable of happening again. That said, some solutions do market themselves as a permanent fix for a bad head gasket. That means that they can make it almost as good as new again. Keep in mind that doesn't mean it's going to be indestructible; it just means that it's able to hold up to a standard amount of wear and tear that your head gasket would normally be able to endure even if it hadn't been fixed.
If the underlying problem that caused your head gasket to blow it in the first place hasn't been addressed, then one that you fixed with a head gasket sealer is likely to fail on you again.
What Causes a Head Gasket to Blow?
There are a number of potential causes for a blown head gasket in your car. Let's take a look at the most common ones that could be the cause of your problems.
Overheating: Arguably the main cause of blown head gaskets is an engine that runs too hot. Your engine has an optimal temperature range and the temperature certainly does get very high, so a head gasket is able to handle high heat. However, if you're noticing that the temperature gauge on your dashboard is routinely running into the red that's going to cause any number of problems for your vehicle including extreme wear on your head gasket. This problem snowballs because if you blow a head gasket it is going to cause your oil and coolant to leak and mix together, reducing the ability of both of them to do their job and effectively causing your engine to overheat even more. So once the problem happens it actually makes itself worse.
This is why it's important to make sure you're having routine maintenance done exactly when your owner's manual tells you that it needs to be done. Your engine is far less likely to overheat if you're sticking to a strict schedule of changing your oil when it needs to be done and doing the same to your coolant as well.
Your owner's manual will tell you for sure exactly how long your vehicle can go, but you can expect that your oil will probably need to be changed every 5000 miles to 7500 miles, although this can vary depending on the model you drive and how you drive it. Likewise, your coolant is going to need to be changed about every 30,000 miles or so.
Problems with Pre-Ignition: They call this detonation sometimes and it's what happens when there is an issue with how combustion takes place in your engine. If you have a lean fuel mixture, which is to say too much air and not enough fuel, or you're using some kind of low-octane fuel then the timing of your combustion reaction can be thrown off. This can alter the pressure that builds up in the cylinder by starting your second ignition in a way that makes it basically run into the first one. This ends up creating a sound you can hear, what we call engine knock, and sends a shock wave through your entire engine which can damage the gasket head.
When it's pre ignition the same sort of problem happens and creates kind of an engine ping because your ignition process started before the spark plug fired thanks to your timing being off.
Signs of a Blown Head Gasket
When your head gasket fails on you, you're going to experience a few common symptoms to alert you to the problem. Like we said, the chief problem you're going to experience with a bad head gasket is overheating but there are definitely some other problems you should be on the lookout for as well.
Contaminated Oil: If your head gasket isn't working properly then your oil and your coolant are going to end up mixing together. You'll be able to tell this has happened when you check your oil and see that it's taken on a milkshake like quality. It will be thick and white in colour as a result of cooling having contaminated it. Oil cannot do its job properly when it is in this condition so you're going to need to have your oil changed quickly.
Contaminated Coolant: Just as coolant will contaminate your oil the opposite will happen as well. When oil gets into your coolant you create the same mixture in your radiator. This will not be able to maintain the temperature of your engine properly so you're going to need to do a coolant flush as well to get this problem fixed.
While coolant contaminated oil is going to have a frothy, milkshake consistency it will be slightly different when the oil contaminates your coolant. This time it's going to make a coating over the top of the overflow reservoir and even on your radiator cap that might remind you of mayonnaise.
White Smoke: Because coolant is going to be leaking into the combustion chamber itself as your engine is operating at high temperatures the coolant will evaporate and will be released out of the back of your car in the form of white smoke. If you start burning oil, then you'll notice the smoke is going to take on a grey or blue colour.
Engine Misfires: If you're finding that your engine is misfiring, especially on startup, then this could be caused by a failed head gasket causing issues with your cylinder compression in the timing of your combustion reaction.
External Leaks: This is a less common symptom of a blown head gasket and can also be easily misdiagnosed as a blown head gasket when it might be something like the cover gasket or something else causing problems. Still, it's possible that if you're experiencing external fluid leaks such as oil or coolant running down the side of your engine block or the cylinder head it could be a problem with your head gasket having a crack in it.
The Bottom Line
A blown head gasket is one of the most frustrating repairs that you'll have to deal with in your engine. For such a small and inexpensive part on its own, the time, effort, and money associated with fixing it can spiral out of control very quickly. Fortunately, head gasket leak sealers really can save you a lot of aggravation by fixing the problem, even if it's only temporary.
The only thing you really need to remember is to check the directions closely to make sure you're buying the right product for your vehicle. Larger engines are going to need a larger quantity of sealant to be run through them so make sure you've bought enough if you happen to have a large V8 in your vehicle, for instance. Follow the directions closely to make sure the product is able to do its job as well as it can and hopefully within 30 minutes to an hour your car will be working the way it's supposed to again.
Given how expensive a blown head gasket repair can be, you've really got nothing to lose when it comes to at least trying out some head gasket leak sealer.