7 Symptoms of a Blown Head Gasket
Over time, aging engines become more susceptible to failures such as a blown head gasket, one of the most dreaded problems for car owners. Although not very common, a blown head gasket can lead to serious driving problems and costly repairs if not caught right away. Learning to recognize the symptoms of a blown head gasket can help you repair it right away and get your car back on the road sooner.
What is a cylinder head gasket? A cylinder head gasket is a special gasket that is placed between the inner engine block and the cylinder head. This seal prevents combustion gases from escaping the engine’s cylinders while simultaneously preventing coolant and oil from migrating into the engine’s combustion chambers.
Depending on the exact arrangement of the cylinders in a particular engine, every engine has one or two head gaskets. In-line engines have only one cylinder head, and therefore only one cylinder head gasket. In contrast, “V” configuration engines have two separate cylinder heads, and therefore a total of two cylinder head gaskets.
Today, most cylinder head gaskets are made from multi-layer steel (MLS). These seals consist of 2-5 layers of thin steel, usually covered with a rubber coating.
Engine cylinder head gaskets are tightened between the engine block and cylinder head using precisely tightened cylinder head screws. Often these bolts are torque-to-yield type, stretching as they are tightened to provide the best clamping seal possible. Engine cylinder head bolts are also tightened in a specific way, often starting from the center bolt and working outwards.
What does it mean when a cylinder head gasket “seizes”?
The term “blown head gasket” is used to describe a head gasket that is structurally damaged. This damaged area of ​​the head gasket prevents a proper seal between the block deck and the cylinder head of the engine. This causes leakage, which can manifest in a variety of ways.
Depending on the exact location of the defect in the cylinder head gasket, a variety of issues can result. Coolant or oil may flow into one or more cylinders of the engine or out. Additionally, oil and coolant may get into each other and the fluids may mix.
A leaking head gasket can also leak combustion gases into the engine’s cooling system or into the crankcase itself. The most serious problems associated with a blown head gasket include overheating and loss of compression.
Signs of a blown head gasket
A blown head gasket can exhibit a variety of symptoms that can help with diagnosis. Below are some of the most common symptoms of a failed head gasket.
1) White exhaust smoke
White exhaust smoke can occur when a blown head gasket causes coolant to leak into one or more cylinders of the engine. This is a by-product of coolant burning during combustion and flowing through the vehicle’s exhaust system.
2) Continuous loss of coolant
If your car seems to be constantly losing coolant despite the absence of any visible leaks, your engine’s head gasket is most likely the culprit. Due to the internal nature of head gasket leaks, coolant often burns without any visible leaks.
3) Formation of bubbles in the cooling system
A slow and steady buildup of coolant bubbles inside your vehicle’s radiator or expansion tank is often an indication that combustion gases are being directed in the wrong direction. Such a condition is relatively easy to check with the use of a dedicated combustion gas detector.
4) Milky Coolant
Cylinder head gasket leaks often show up due to an oil and coolant change, which often drastically changes the condition of the coolant. When this happens, the coolant will turn gray or brown and appear milky.
5) External Oil/Coolant Leak
In some cases, a blown head gasket can cause a visible coolant or oil leak. This leak occurs at the junction of the engine block and the cylinder head above it, but oil can reach the exhaust. Rarely, with this type of leaking fluid, small air bubbles may be observed as a small amount of compression also escapes.
6) Engine Overheating
A blown head gasket often leads to engine overheating. This can happen for a variety of reasons, but the most common cause is related to loss of coolant. Additionally, leakage of combustion gases into the engine’s cooling system can also cause overheating.
7) Poor Engine Performance
Loss of compression due to a damaged head gasket will almost certainly result in poor engine performance. This is especially true if a head gasket blows between two separate cylinders, as compression can escape through open valves in the adjacent combustion chamber.
