When it comes to your automobile, a blown head gasket is just about the most expensive diagnosis there is, short of what happens if you continue to drive with your head gasket blown. The result of that could be catastrophic engine failure and a trip to the junk yard for a new engine — or to a car dealership for a new vehicle.
What is particularly distressing about how expensive a head gasket is to replace and the absolute necessity that it be done, is how simple and inexpensive the part actually is. Head gaskets are merely thin slices of metal, perhaps a composite, with a variety of holes in them. They don’t move, produce a spark, transfer a fluid, create electricity or really do anything. They’re just there.
What Is a Head Gasket?
The head gasket in a car is just a metal divider, a fraction of an inch thick, that stands between the moving parts of the engine that require oil lubrication and relatively cool conditions, and the combustion chamber of the engine that requires fuel, air and fire to create an explosion. Oil in the combustion chamber fouls up the works and prevents it from functioning efficiently. Heat from the combustion chamber can burn up the moving parts. Coolant leaking into the motor oil reduces lubrication and gums up the mechanical elements that make the wheels turn. And much, much more.
In other words, that simple head gasket stands between a smooth-running engine and disaster. When a head gasket leak develops, oil can seep into the coolant and vice versa. The heat and pressure of the combustion chamber can cause warping in the cylinders. Oil can drip through the gasket into the combustion chamber and prevent combustion or cause the engine to misfire. Oil in the coolant can reduce its cooling capacity and damage a host of parts like the catalytic converter.
If the mechanic diagnoses a blown head gasket, it needs to be fixed immediately. Failing to do so will lead to total engine failure, and soon.
What Is the Cost to Replace a Blown Head Gasket?
You can drive with a blown head gasket until the engine is destroyed. An engine overhaul is a major undertaking and costs $3,000 to $5,000, mostly in the many hours of labor required. Rebuilding a truck engine can cost much more than that.
By that measure, replacing the fifty-dollar head gasket is cheap – an average of $1,500 to $2,000. But when it’s coming out of your wallet, it feels like a fortune.
Why does a blown head gasket replacement cost thousands of dollars when the part itself is under a hundred bucks? Because there is so much labor involved. The head gasket sits between the engine block and the cylinder head, all the way in the back. Almost everything under the hood must be taken apart, moved or removed to access the head gasket.
That is no simple matter. The battery must be disconnected, and the oil and coolant drained. Wires and hoses that are repositioned or removed must be labeled so they can be reattached. Many components such as the valve cover, cylinder head, and intake and exhaust manifolds require their fasteners be removed in a certain sequence to avoid warping or cracking.
After the head gasket is replaced, the timing belt or chain must be reset to its proper alignment and everything else must be returned to its previous position. If all that sounds daunting, it is just a preview of the complexity of the work. Head gasket replacement is a job that can easily take 10-20 hours.
As long as you are paying a mechanic to take everything apart, it makes sense to have them do an inspection of all the parts. If anything is close to needing replacement, this is the time to do it. That will save you money in the long run, but it can push the head gasket bill higher.
How Do You Know Your Head Gasket is Blown?
Many of the symptoms of a blown head gasket are signs of other problems as well. Conversely, many seemingly simple issues are the first signs of a blown head gasket. It is important to pay special attention to these signals because early diagnosis might be able to save you thousands of dollars.
1. The radiator constantly requires additional fluid. This is a common issue that normally does not indicate anything as disastrous as a damaged head gasket. It could be a small leak in a cooling system hose or in the radiator itself. If you find yourself topping off the radiator repeatedly, get it checked for leaks. It’s likely one will be identified and the problem solved. If no leak is identified, a mechanic should search for other symptoms of a blown head gasket.
2. The temperature gauge shows the car running hotter than usual. Again, this may or may not be related to a head gasket leak. Certain normal conditions can heat up the engine. Towing a heavy load, running the air conditioning full-blast, and stop-and-go driving on a blazing hot day can all drive up the temperature. So can loss of coolant, which can happen for a variety of reasons. A mechanic can search for more likely causes before concluding it is a blown head gasket.
3. Bubbles are forming in the radiator and coolant reservoir. This might be nothing. It might be a blown head gasket. Bubbles can form when air gets into the cooling system. This can result from a poorly fitting radiator cap or even from nothing at all. If it persists even after fixing the cap, it is time to suspect trouble.
4. Thick white smoke is coming out of the exhaust pipe. It is important to distinguish white smoke from steam. Condensation can occur when a vehicle is started after standing still on a cold day. In that case, a thin stream of clear or white smoke can emanate from the tailpipe. It is not a problem and should disappear after a minute or so.
Thick white smoke, especially if it is emitted in bursts, is a sign that coolant is leaking into the engine’s combustion chamber. This is never a good thing and should be investigated. Even if it is not a blown head gasket, a crack in the cylinder head or engine block is also big trouble.
5. The dashboard temperature gauge has pinned. Stop the car! Make sure there is coolant in the radiator. If not, address the coolant problem and buy time to determine if there is an underlying issue.
6. The oil is discolored. If coolant crosses the head gasket and leaks into the engine oil, it can give the oil a frothy look, like someone has just whipped up some warm milk. Milk is good for you, but frothy engine oil is not.
7. The engine misfires when starting up. Again, this could have a host of causes, most of them not quite as potentially catastrophic as a blown head gasket. When combined with white exhaust, that is a tell-tale sign that coolant is leaking into the combustion chamber. Get that checked immediately.
If Repairing the Head Gasket Isn’t an Option
If the head gasket is indeed blown or damaged and doing a hard part repair isn’t an option, using a head gasket sealant is a good solution. BlueDevil Pour N Go Head Gasket Sealer is poured into the radiator and circulated through the engine to find and seal leaks in metals and composites. It then bonds to a variety of surfaces for a permanent seal.
While nothing is better than the original parts or replacement parts made specifically for a vehicle, sealant is a great backup plan that can provide a permanent solution while averting large car repair bills.