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Our Engine Blew Its Head Gasket: Here’s Why and How We Fixed It

Our Engine Blew Its Head Gasket: Here’s Why and How We Fixed It

If you work with engines long enough, you are eventually going to encounter a head gasket problem. Over the years, we have had 3 engines with head gasket problems. A 2.5 Subaru boxer, a 4.0-liter backhoe, and our 6.7 Cummins.

If your engine blows its head gasket, it can be a frustrating and expensive problem to fix. A blown head gasket can cause various issues, and we experienced almost all of them. Whether you’re a mechanic or a car owner, understanding how to fix this problem can help you save time and money in the long run.

Today, we’re sharing our story to help you know what to do if you experience the same issue. We are also going to take a look at what fixes are available, including the pour-in liquid fixes. Let’s get started!

Fixing a Blown Head Gasket ~ The Right Way

What Is a Head Gasket?

To understand what a head gasket failure can cause, you need to understand what a head gasket is and does. It sits between the two main parts of the engine, the engine block and cylinder head to create a tight seal. Its primary job is to prevent oil, coolant, and other engine fluids from mixing. This keeps the combustion process entirely within the engine’s cylinders.

The head gasket has thin layers of metal and composite materials designed to withstand high temperatures and pressure. It must withstand the intense heat the engine’s combustion process generates. In addition, the cylinder head has engine coolant and oil passages that flow between the head and the block. So the head gasket is responsible for containing combustion, coolant, and oil passages.

location and what a head gasket is diagram of cutaway of an engine
In this engine cutaway, you can see the two main parts of the engine the block and head. Between them sits the head gasket

If the head gasket fails, it can cause a host of problems depending on where it failed. The problem could be with combustion, oil, coolant or a combination.

How Do You Know If You Have a Blown Head Gasket?

Like many automobile problems, there are often several signs that you’ve blown a head gasket. However, not all head gasket failures are the same because of the reasons mentioned above. You may have one or more of the most common symptoms. The primary symptoms are coolant, oil or combustion related. If you experience these standard issues, have a mechanic you trust to look at your vehicle.

Coolant Symptoms

One of the most familiar signs of a blown head gasket is the vehicle overheating. A loss of coolant often causes this. A blown gasket sometimes allows coolant to escape the system and usually enters the cylinder and burns up. You’ll likely notice the engine’s temperature climbs, especially if driving at high speeds or for extended periods. Sometimes you can even notice it in the exhaust.

Burning coolant sometimes causes white smoke to come from your exhaust that has a sugary smell to it too. This indicates that the coolant is leaking into the cylinder and mixing with the fueling as it burns.

When our Subaru gasket went it was overheating and blowing exhaust gasses into the coolant.

Cumbustion Symptoms

Another sign is a lack of power, especially when going uphill or accelerating. A blown gasket can allow compression pressures to leak out of the engine. This can drastically reduce the vehicle’s ability to generate the power necessary to deliver the performance you expect.

Many times a head gasket will also allow exhaust to leak into the coolant and might bubble inside the coolant tank. A simple test for this is to start the engine when cold with the radiator cap open. Look inside for any bubbling that smells like exhaust. Sometimes you cannot see it, and a simple tester kit can indicate if it’s leaking exhaust.

UView 560000 Combustion Leak Tester
  • Fast, Economical and Accurate method to test for combustion gas...
  • 16 ounce test fluid good for 16 applications
  • Works on gasoline and diesel engines
Using a Block Tester to Find a Headgasket Leak

Oil Symptoms

Since most head gaskets also have oil channels, low oil pressure oil leaks or burning oil can be head gasket related. If the leak is internal it sometimes can be hard to diagnose.

Some symptoms will require more knowledge and expertise to recognize. A professional mechanic can do a pressure test to ensure that the cylinders get the proper pressure. If the pressure is too low, it could indicate that your vehicle has a blown head gasket. 

Pro Tip: Something not smelling right with your car? If your car smells like rotten eggs, Here’s What’s Wrong.

Why Do Head Gaskets Blow?

There are many reasons that head gaskets blow. An overheating engine is one of the most common reasons for head gaskets blowing. When this occurs, the temperatures inside the engine can get incredibly hot, which can cause the head gaskets to warp or crack. This can develop leaks in the system and cause substantial damage.

Additionally, a head gasket could blow due to an improper installation or factory defect. There are some cases where it could leave the factory with damage. Unfortunately, you may only uncover the issue once you purchase the vehicle and put it to the test. Hopefully, if this is the case, you’ll catch it before your warranty expires.

factory defect in head gasket
Here is an example of a damaged new head gasket. This was getting installed on our truck when our mechanic noticed a small pinch. While a minor defect, it could cause catastrophic problems because the gasket is so critical.

Some engine designs are more susceptible to blown head gaskets than others. Engines with horizontal designs allow the gasoline to sit on the gasket for an extended period. Over time, the gas can cause damage to the gasket. This isn’t an uncommon issue for many Subaru engines that are horizontally opposed and we have replaced a few Subaru gaskets. However, all types of engines can have a head gasket blow due to normal wear and tear.

Can You Drive Your Vehicle With a Blown Head Gasket?

While it is possible to drive a vehicle with a blown head gasket for short distances, experts generally do not recommend it. Driving with a blown head gasket can cause further damage to the engine and may result in total engine failure, which can be expensive to repair or replace.

If you suspect your vehicle has a blown head gasket, it’s crucial to address the issue as soon as possible. Continuing to drive with a blown head gasket can cause the engine to overheat and lead to further damage down the road. Bring your vehicle to a qualified mechanic as soon as possible to avoid worsening the situation.

Holding head gasket to replace in engine
Repair your head gasket as soon as possible to ensure no further damage is caused to your vehicle.

How Do You Fix a Head Gasket?

There is really only one true fix to a leaking head gasket, which is to replace it. Replacing a blown head gasket is typically not a DIY job. It will require disassembling the engine or removing it from some vehicles. An alternative temporary fix many try is a liquid head gasket fix. Because the head gasket is so much work to replace there are chemicals you pour into your cooling system that can plug up a leak.

Do Liquid Head Gasket Sealers Work?

Liquid head gasket sealers are designed to be poured into your vehicles cooling system. They will only work if the leak is between the head gasket and coolant. Exhaust or air leaks and oil leaks cannot be fixed this way. They work by flowing into the leak and then hardening from heat or exhaust gas to create a seal. They are typically made of a combination of chemicals, including sodium silicate, which reacts with the metal in the engine to form a ceramic-like seal. The sealant also contains small particles of metal or ceramic that can help to fill any gaps or holes in the gasket or other engine components.

While liquid head gasket sealers can be effective in temporarily sealing leaks, they are not a permanent solution, and they should not be relied upon as a long-term fix. In some cases, they may even cause further damage to the engine if used improperly. Therefore, it is always best to consult a qualified mechanic to diagnose and repair any engine problems rather than relying on a temporary fix.

We tried this repair on the engine for our tractor, and it has been working well for about 100 hours. However, we would not attempt this on a vehicle that needs to be dependable.

Do Head Gasket Sealers Actually Work (FULL 2yr TEST with Engine Teardown)

How Do You Rplace A Head Gasket?

Head gasket replacement is a complicated procedure that involves significant engine disassembly. To do this job, you must remove the head from the engine. This is a labor-intensive task, so work through the list of symptoms to ensure it’s the head gasket. The procedure to remove the engine head will differ significantly per engine. However here are some of the general steps most engines require.

Start by draining the cooling system of all fluids. Disconnect the battery to prevent potential shocks or sparks. Remove the air intake and intake manifold. Note where all the wires and hoses connect so you can reinstall them correctly afterward. This is also the time to disconnect the fuel system and exhaust manifold.

Depending on your engine, you may need to remove engine-driven accessories and the timing cover. Remove anything bolted to the cylinder head.

Remove the cylinder head from the engine. Vehicles with the camshaft inside the engine block can remove the cylinder head bolts and the cylinder head from the engine. However, if your car has camshafts inside the cylinder heads, remove the timing belt or chain before removing the cylinder head. If you are using an overhead cam engine be sure to understand how timing works before removing the head.

Check the cylinder head for warping or damage. Determine whether the cylinder head needs rebuilding, replacing, or reusing. If replacing, compare the new gasket to the old one to ensure everything is the same before you start reassembly.

The reassembly process means repeating everything you’ve taken apart in reverse. Connect every wire and hose. It’s never a good sign if you have extra bolts, clamps, and other leftover parts.

cummins engine and head
This is our engine removed with the head separated and about to be reinstalled.

How Much Does It Cost to Have a Head Gasket Fixed By a Professional?

The cost of fixing a blown head gasket can vary widely depending on the vehicle’s make and model, the damages, and the mechanic’s location and experience. However, as a general guideline, the cost of repairing a blown head gasket by a professional can range from $1,000 to $5,000 or more.

The head gasket cost is relatively low, usually ranging from $50 to $200. However, the labor fees for replacing the gasket can be costly. The engine may require complete disassembly, and you may need to replace or repair other parts. This is also the time to replace any parts nearing the end of their expected life. 

It’s crucial to obtain a detailed estimate from a qualified mechanic before proceeding with repairs. Costs can vary widely depending on the issues with the engine and the shop doing the work. In some cases, it may be more cost-effective to replace the engine rather than repair the blown head gasket.

Pro Tip: Need something fixed on your RV? Keep an eye out for these 5 Red Flags to Watch for With an RV Repair Shop.

Fixing a Blown Head Gasket ~ The Right Way

Is It Worth Fixing a Head Gasket?

Whether it’s worth fixing a blown head gasket depends on several factors. It would be best if you considered the age and condition of the vehicle, the cost of repairs, and the vehicle’s overall value when making your decision. 

Fixing a blown head gasket can be a complex and expensive process. If the vehicle is newer, in good condition, and has significant value, it may be worth fixing a blown head gasket to keep it running. However, if the vehicle is older or in poor condition, it may be more cost-effective to replace the car instead.

Have you experienced any symptoms of a blown head gasket in your vehicle? 

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About Mortons on the Move

Tom & Caitlin Morton of Mortons on the Move gave up the stationary life for one where they are constantly on the move. They are full-time travelers, television hosts, and digital media producers.
They left their jobs, sold their house and possessions, and hit the road in September 2015 in their full-time “home on wheels”. Since then they have traveled the US, Canada, and even internationally by RV.
Now, they are Discovery Channel & PBS TV Co-stars of “Go North” on Amazon Prime Video, co-founders and instructors of RV Masterclass, and contributing authors for and an Arizona travel guide.

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Tuesday 21st of March 2023

My car - a 2007 Chevy Equinox with 72,000 miles- was diagnosed with a blown Head Gasket My mechanic used the 'liquid fix' - said it would be OK for a while and not to stress the engine by taking long trips and watch for overheating and any loss of coolant. Can't afford a new car - the 'fix' would be more than I can afford. Any suggestions????

Mortons on the Move

Wednesday 22nd of March 2023

Ugh its never fun, I have had those liquid fixes last a few years without problems. Try not to put your foot to the floor, and it might last longer than you expect. With that low of miles its probably worth fixing the gasket at some point if possible.