Blown Head Gasket Symptoms

Blown Head Gasket Symptoms – Fix These Before Your Engine Seizes

An engine is without a doubt the most complex and intricate part of any car. It’s a component with an array of tiny sub-components, all moving in unison and concert with one another inside the engine. In doing so, the countless minuscule sections and pieces that make up an engine also mean that there’s a lot to go wrong when it does. So, why is it so crucial to look out for blown head gasket symptoms?

Well, it’s simply down to the fact that the head gasket is among the most consequential parts of your engine. At first, it may seem quite simple… It’s just another gasket that seals the engine together, and prevents oil and coolant from mixing, as well as gases and pressure from escaping, right? Hmm, while that appears trivial, a blown head gasket is a serious matter. And one that could seize up your motor.

When the head gasket “blows”, oils and coolants mix. This deprives the engine of coolant, needed for cooling down the hot engine, as well as oil, required for lubrication. That alone guarantees quick destruction and irreparable internal damage to the engine, if not fixed promptly. Not to mention the exhaust leaks, affecting performance. Thus, the need to look out for blown head gasket symptoms.

What Is A Head Gasket?

Before we look closely at blown head gasket symptoms, it might help to learn more about what it does inside your engine. So, what is a head gasket, anyway? As its name suggests, the head gasket is just a gasket, defined as a sealant to close any gaps between two solid parts. In the case of the head gasket, it creates a seal between the cylinder head (which covers the combustion chamber) and the engine block.

Overall, it has several functions:

With these in mind, we could conclude that the head gasket is indeed a pretty important piece of your engine. If there is a loss or reduction of pressure in the combustion chamber, your air-and-fuel mixture might not ignite and combust thoroughly. Remember that compression is a key player in your engine’s combustion process, alongside the presence of fuel and air. Without it, performance will be affected.

Moreover, there’s the oil and coolant. Once again, they both play crucial roles inside the engine. Oil is absolutely necessary to lubricate the many moving parts of an engine. Thus, ensuring that they won’t grind each other. Whereas, coolant is used to help cool your toasty engine, where its insides could get as high as 6,000°F. With cross-contamination of oil and coolant, neither would perform as intended.

Blown Head Gasket

Another interesting point to note is the term “blown”. What does it mean by a ‘blown head gasket’. Is it defined as an actual explosion? No, rather, the use of the word “blow” is another way of saying that a leak in the head gasket is present. To put it another way, a “blown” head gasket is now structurally compromised. Or, that it can’t maintain a seal between the combustion chamber and engine block.

The actual damage and what effects it has on the engine will vary. In short, it’s dependent on where is the point of failure within the head gasket. Based on what part of the head gasket that’s blown, it may cause some of these problems:

  • Coolant and oil would start leaking into the cylinders, where combustion takes place. For starters, this will impact the combustion process, and adversely affect your car’s performance. Plus, it would mean that there’s less (or no) oil or coolant elsewhere to cool down and lubricate the engine.
  • Oil and coolant would enter each other’s passageways or channels, and start to mix. This is bad, as the contamination would essentially negate the functionality of both fluids. The coolant (now containing a bit of oil) isn’t as effective at cooling, which leads to your engine overheating. The oil (which now has a bit of coolant) isn’t as good at lubrication, leading to parts of your engine grinding each other down.
  • Combustion gases (i.e. fuel vapor, air, and exhaust fumes) would now escape out of the combustion chamber. It could leak out into the atmosphere, which would manifest as toxic fumes. Alternatively, it may leak out into the engine and crankcase, reducing compression and impacting performance. Or, it may leak from one cylinder into an adjacent cylinder, with similar consequences.

What Causes You To Notice Blown Head Gasket Symptoms?

In some cases, blown head gasket symptoms appear organically. They’re usually engineered and made to last a long time. The average lifespan of a head gasket (if well cared for) is around 200,000 miles. In the hands of most people, 200,000+ or so miles is the lifetime of an entire vehicle. Therefore, it’s not a particular component that’s regularly replaced or has to be worried about. So, how can it “blow”?

For the most part, blown head gasket symptoms appear due to regular wear and tear. Your engine is a component that sees countless explosions, ignition, and detonation within the combustion chamber. Being sealed by the head gasket does mean that the latter will absorb quite a lot of that energy. All of the heat, pressure, vibration, shock and mechanical stresses put a lot of pressure on the head gasket.

Blown Head Gasket Symptoms

If not from the engine itself, your car moving along is enough to wear out the head gasket, in time. As you drive, vibrations and impact reverberate across your vehicle and can end up concentrating on the head gasket. This is especially true for the head bolts that keep the head gaskets in place. Over time, it can weaken, break, stretch, and maybe even warp. Combined with friction, it’ll cause a blown gasket.

Otherwise, blown head gasket symptoms appear due to one factor – human error. If you, as the owner of your car, fail to maintain and service it regularly, it heightens the chance for the head gasket to fail, or “blow”. With sufficient coolant flushes, oil changes, or just a check-up every once in a while is more than enough to prevent this. Here are some of the most usual causes of why a head gasket blows:

1. Overheating

Or, continuously running your engine at high temperatures. When your engine overheats, this leads to the metal in and around the head gasket expanding. Once it cools down, it retracts. Repeat this cycle long enough, and it’ll put an enormous amount of strain onto the head gasket. It does so by creating a separation between the cylinder heads and engine block, compromising the head gasket.

2. Pre-Ignition

It’s defined as the sudden ignition of fuel and air within the combustion chamber, outside of the flame front (which is ignited by the spark plugs). This improper combustion will put a significant strain on the head gasket, by damaging the head gasket’s firing rings. Eventually, causing the engine’s compression to drop. If it’s not fixed right away, this then leads to combustion gases and fumes leaking out.

3. Detonation

This is an instance inside the cylinders (or, the combustion chamber) where the ignition is taking place at a slower pace than usual. When it happens, this forces pressure to build up. Consequently, when a second ignition is about to occur, it collides against this pressure. Detonation inside the engine would release a lot of sound and vibration. The latter of which will reverberate and wear out the gasket.

4. Poor Installation

Head gaskets have incredibly tight tolerances inside your engine. As such, it needs to be installed and fitted precisely. In particular, there are those head bolts that mount the head gasket onto the cylinder heads. Failure to torque the head bolts to their exact settings will create looseness. Or, perhaps re-using worn-out head bolts, or maybe not tightening them in the right sequence. This leaves room for leaks.

5. Hot Spots

Some engines are susceptible to creating hot spots between the cylinder heads and the cylinders. This is similar to overheating, in a sense. But instead of the entire engine heating up to an uncomfortable level, hot spots only impacts certain sections of the engine. Nevertheless, hot spots will cause metals in and around those affected areas to expand and contract rapidly. Thus, wearing out the gasket.

What Are The Symptoms Of A Blown Head Gasket?

Now, we can move on to blown head gasket symptoms, and how to spot them. As we mentioned earlier already, a head gasket blowing isn’t a scenario to be taken lightly. If not fixed or replaced quickly, that could cause substantially more costly and complicated issues down the line. Primarily, with the engine seizing up or failing entirely. Therefore, it’s best to be on the lookout for these tell-tale signs:

1. White/Blue Exhaust Smoke (Coolant/Oil Burning Up Inside The Engine)

In colder weather, it’s normal to see white smoke or fog emitting from the tailpipes. Leftover water or condensation will gradually burn away, and you can go on your merry way. However, if all those white plumes of smoke persist after several minutes, and continue to thicken, you have a problem.

Among other potential woes with your engine, thick white exhaust smoke is indicative of a blown head gasket. This points to the fact that coolant (or antifreeze) has entered the cylinders (or the combustion chamber). In so doing, the coolant is being burnt up and ignited during the combustion process.

Mind you, coolant doesn’t ignite. Rather, the burnt remains and by-products of coolant in the cylinders will leave the exhaust. Sometimes, the white exhaust smoke might have a blueish tint, or it might look akin to steam. The latter is probably due to coolant burning away, creating steam in the exhaust.

If you see a purely blueish smoke, that’s also one of the blown head gasket symptoms. In this case, the blue color is due to oil being burnt inside the cylinders, not the coolant. You can try to give the exhaust a nose check. If it’s coolant, then the abovementioned white smoke should have a sweet scent.

2. Engine Overheating (Losing Coolant, Impacting The Engine’s Cooling)

As we’ve learned thus far, constant overheating will result in wearing out and compromising the head gasket. Reciprocating that instance, a blown head gasket will also cause overheating problems. It’s a side effect of coolant (or antifreeze) leaking out from the cooling system, and into the engine.

The loss of coolant from the cooling system will perpetually reduce its ability to cool down the engine. Over time, this will get worse as more and more coolant leaks away. This is made worse by oil leaking into the coolant, and contaminating it. Either way, your car’s cooling system can’t perform as well.

3. Milky Residue In The Oil (Contamination With Coolant/Antifreeze)

Speaking off, it could be that coolant is leaking into the oiling system. Thus, contaminating the engine oil. You could notice this by checking the oil reservoir in the engine bay. Pay close attention to the oil’s color and consistency. Does it look more like a milkshake rather than a greasy oily substance?

Furthermore, does that greyish and brownish “milk” also appear sludgy and viscous? You might spot it being stuck onto the oil filler cap, as well as the dipstick, and within the reservoir. This is what happens when the coolant gets mixed in with the oil. You might see this “milk” in the coolant reservoir, as well.

4. Bubbling Coolant (Combustion Gases Leaking Into The Coolant)

Since we talked about the dreaded “milk” earlier, remember to check the coolant reservoir after going through the oil reservoir. If the oil’s leaked into the coolant and cooling system, you might still see milk in the reservoir. Additionally, the milky texture would be seen inside the radiator, and elsewhere.

But what if, upon looking into the coolant reservoir (make sure the engine has been cooled down!), a bubbling effect is seen? If you see the coolant bubbling away, it’s a sign that combustion gases leaked past a blown head gasket, and into the cooling system. What you’re seeing there are air bubbles.

5. Poor Performance (Combustion Gases Leaking Out Of The Engine)

Driving around, you might notice a few of these blown head gasket symptoms. Are you noticing how a vague hissing sound is emanating from the engine bay? If so, that’s an exhaust leak you’re hearing, as a result of a blown head gasket. And are you experiencing poor performance from the engine?

It might be felt as a loss or reduction in power, sluggish acceleration, and a rough running engine. Just like that hissing sound, poor performance is attributed to a blown head gasket. This is due to fuel and air, alongside exhaust gases, leaking out of the combustion chamber, through the leaky head gasket.

This lowers the compression inside the engine, which ultimately compromises the performance that it normally produces. If the head gasket is blown wide open, you might find coolant and oil seeping into the combustion chamber, and burning with the fuel and air. Once again, you’ll spot a drop in power.

These blown head gasket symptoms can appear early on. If the situation worsens further, you might then notice misfires, or the engine stalling while idling or in the middle of driving. Moreover, you may experience rough idling from the engine. All in all, pretty bad, and should be looked into ASAP.

6. Fluid Leaks (External Oil And Coolant Leaks, From The Gasket)

A blown head gasket can cause fluids like coolant and oil to leak into the engine. On the flip side, head gaskets blowing could alternatively cause them to leak outside of it, as well. Coolant might leak out of the passageways around the head gasket, and slowly trickle down onto the ground below your car.

Similarly, motor oil will escape their respective oil galleries, and leak down, too. This can lead to some of the issues mentioned earlier, like overheating. Worse, having your head gasket leaking oil can turn into a fire hazard. That oil might land on hot components on the engine, burning them up.

7. Dirty Spark Plugs (Oil And Coolant Burning Up Inside The Engine)

In this situation, the spark plugs might dirty up in one of two ways. Are you seeing small, white marks and deposits on the spark plugs? These are left behind by coolant burning up inside the cylinders, as it leaks past a blown head gasket. You may see these deposits around the spark plug electrodes.

If not, are you perhaps seeing black burn marks and fouling on the spark plugs? Or, perhaps that oily sludgy residue that’s consistent with motor oil? Easy enough to explain, as these fouled marks are left behind by engine oil burning up inside the cylinders. A blown head gasket might be why.

Can You Drive With A Blown Head Gasket?

Ah, but what if you noticed these blown head gasket symptoms, but aren’t in the right time and space to be fixing them? Could you safely keep on driving, even with a blown head gasket? At the end of the day, driving with a blown head gasket is a bad idea. Even smaller issues, such as fluid leaks, sluggish performance, or overheating, will eventually snowball into something larger, and more catastrophic.

Worse comes to worst, a blown head gasket could be bad enough that it causes irreparable damage inside your engine. Hence, forcing you to spend thousands on rebuilding the engine. Rebuilds involve taking the engine apart, and stripping them down. Then, reconditioning or replacing individual parts that may have been damaged. Alternatively, you’d be forced to replace the engine completely.

Blown Head Gasket Symptoms

The latter is a realistic scenario if you’ve ignored fixing your blown head gaskets for too long, and have allowed it to cause too much internal damage. Another possible side effect of driving with blown head gaskets is damaging the catalytic converter. This will happen if you allow burnt oil and coolant to flow continually into the catalytic converter. Which, it was never designed to work with, and will wear out.

However, it’s not as though you’re explicitly banned from driving with a blown head gasket. Based on how bad the symptoms may appear, you might have a bit of time to drive down to a nearby mechanic. There, you can fix or replace the head gasket. Just make sure you don’t drive it for long or too hard. Or else, it’s recommended that you simply call a tow truck, and have it towed down to the workshop.

How Can You Fix These Blown Head Gasket Symptoms?

There are two options for resolving blown head gasket symptoms. If you managed to catch it early on, there’s still a chance for you to repair the blown head gasket. This is a cheaper route and doesn’t ask for too much of your wallet or patience. If the head gasket’s condition is too bad though, there might not be any other choice other than a replacement. While costlier, it’s still cheaper than a new engine.

Here’s some more context as to the two options – repair, or replace:

Head Gasket Repair Cost

This is only applicable if the blown head gasket symptoms are minor. And, you’ve uncovered that the leakage or seepage is only very small. Again, if you’ve managed to pick up on those blow head gasket symptoms pretty early on, you might still have a chance to repair it while the leak itself is tiny.

If that’s the case, you could easily repair it with a pack of sealants. These products fill up gaps or cracks in your head gasket, sealing them in. Most of the time, these sealants are good enough to be classified as a permanent repair, not merely a temporary one. Here are some of the best head gasket sealers.

Product (+ Amazon Links) Price (As Of March 2022)
Steel Seal Blown Head Gasket Fix Repair Sealer $139.95 (For The V8 Sealer)
K&W Permanent Head Gasket And Block Repair With Nanotechnology $24.99 (For 32 Ounces)
Bar’s Leaks Block Seal Head Gasket Fix $23.71 (For 1 Pack)
Bar’s Leaks HEAD SEAL Blown Head Gasket Repair $36.54 (For 1 Pack)
K-Seal Multi-Purpose One Step Permanent Coolant Leak Repair $12.08 (For 8 Ounces)
BlueDevil Pour-N-Go Head Gasket Sealer $29.92 (For 1 Pack)
Gasgacinch Gasket Sealer And Belt Dressing $14.22 (For 8 Ounces)
Permatex High Tack Gasket Sealant $9.08 (For 1 Pack)

Head Gasket Replacement

Otherwise, if the head gasket is blown right through, you have no other choice but to replace it. The bad news with a complete replacement is that it’s never cheap. This is down to two factors. Firstly, it involves a lot of labor hours, owing to the need to disassemble the upper parts of the engine to even get to the head gasket. This will take longer depending on what vehicle (make and model) you have.

Certain vehicles make it harder to access the head gasket. Meanwhile, luxury or performance vehicles might require specific types of head gaskets to meet their standards. Once again, it’s compounding an already high labor charge for the replacement. All this work required is why your blown head gasket is as expensive as it is. The actual head gasket itself (just the parts) isn’t at all pricey in comparison.

Blown Head Gasket Symptoms

Note, these expenses below only cover the replacement of the head gasket alone. It doesn’t include any of the other auxiliary repairs needed. For example, if the coolant and oil have mixed, you’ll have to completely flush and replace both fluids. Combined with other repairs here and there, it will add to the final replacement cost, depending on what needs doing:

Item Cost
Head Gasket (A Complete Kit) $250 To $300
Labour Hours (Assumed 6 To 12+ Hours Of Work, In Total) $1,000 To $2,000
Total Head Gasket Replacement Cost $1,250 To $2,300

Final Thoughts On Blown Head Gasket Symptoms

That then rounds up our look at blown head gasket symptoms, and what you need to look for before irreversible damage is done to your engine. In short, blown head gaskets are right up there as one of the worst problems you could experience as a car owner. While the component itself appears rather simple in its functionality, the side effects of it leaking (or blowing) are highly consequential.

If you don’t patch up that seal in time, it could introduce a myriad of issues within your engine. It goes from overheating to poor performance, with fluid leaks and other serious problems brewing within. It can’t be ignored for too long, or else you’ll have to scrap the entire engine. Head gasket replacements are expensive, too. But if you catch these symptoms in time, a bottle of cheap sealant is all you need.

Frequently Asked Questions On Blown Head Gasket Symptoms

Here are some of the most popular FAQs on blown head gasket symptoms:

Dirt Bike Blown Head Gasket Symptoms

With such hard-driving and often on very rough terrain, it’s fairly easy to wear out the head gaskets on a dirt bike. The symptoms here are similar to that of a car, as we’ve detailed so far. Therefore, you will experience overheating issues, as well as low compression and a loss of power. Aside from that, blown head gaskets on dirt bikes will introduce coolant leaks, especially around the overflow tube.

BMW Blown Head Gasket Symptoms

BMWs, while generally decently reliable, are well known to have suffered from head gasket issues in a few models. The 3-series is one range of its cars that has persistently been plagued with blown gaskets for a little while now. Commonly, this will manifest as overheating if not fixed quickly. Otherwise, you may notice other symptoms, such as coolant and oil mixing, milky residue, and white exhaust smoke.

5.7 Hemi Blown Head Gasket Symptoms

The Dodge RAM is one of the most popular pickups in the States and is famed for its mighty 5.7 Hemi engine. However, this particular powerplant is known for its head gasket issues. Should it fail, similar blown head gasket symptoms will appear. Primarily, in the form of rough idling and a loss of power. You’ll then spot the milky oil and coolant mixture, besides leaking coolant, and the white smoke.

Duramax Blown Head Gasket Symptoms

Just like the 5.7 Hemi, the Duramax series of engines are among the most popular for trucks and other heavy-duty vehicles. Similarly, it can materialize head gasket problems as they age. Familiar signs of blown gaskets would be losing coolant, without there being any noticeable leaks. In addition, there are overheating problems, so you’ll have to keep a close eye out on the temperature gauge.

Symptoms Of Blown Head Gasket On Kohler Engine

Yes, it’s not just two- and four-wheeled vehicles that can blow their head gaskets. Even lawnmowers aren’t safe, either. At least, those lawnmowers that have gas-powered engines, like those made by Kohler. If their head gaskets were to blow, the symptoms would be quite familiar. Besides the oil leaks and smoking exhaust, you’ll also notice the low pressure, which might cause the mower to stall.

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