Symptoms of a bad head gasket
A faulty head gasket can cause engine issues and contamination of coolant and engine oil. The head gasket is a "wall" separating coolant from oil between the engine block and cylinder head. It basically seals the engine's combustion chamber, preventing these fluids from escaping or mixing together.
1. Overheating Engine
One of the most common signs of a failing head gasket is an overheating engine. The head gasket prevents coolant from escaping the vehicle by sealing the engine and cylinder head. But, if the head gasket fails, it'll stop sealing properly, allowing coolant leaks. This leads to low coolant, causing the temperature to rise.
2. White Smoke from the Exhaust (Coolant leak)
A faulty head gasket won't seal the engine's combustion chamber the way it should. Therefore, the coolant sees an opportunity to sneak inside the chamber, consequently burning and creating a white smoke. This smoke usually has a sweet smell due to the ethylene glycol in the coolant.
3. Milky or Frothy Oil
A failing head gasket won't separate coolant from engine oil properly, leading to contamination. The contaminated oil gets a milky, frothy, or chocolate milk-like appearance on the oil dipstick or under the oil cap. This contaminated oil loses its lubricating properties.
4. Loss of Coolant Without Visible Leaks
If the coolant level keeps dropping but you don’t see any leaks, the head gasket may be the culprit. A faulty head gasket leaks coolant internally in the cylinders or oil passages. This internal coolant loss is silent and requires a deeper-level inspection.
5. Rough Idle and Misfires
The loss of sealing by a faulty head gasket lowers compression in one or more cylinders, leading to rough idling, hesitation, or misfires. You may notice the engine shaking or running unevenly, especially when starting the vehicle. Misfires can also trigger the check engine light.
6. Bubbling in the Radiator or Coolant Reservoir
If a bad head gasket doesn't prevent combustion gases from sneaking inside the cooling system, you may see bubbles in the radiator or coolant reservoir when the engine is running. This happens because exhaust gases are jumping inside the cooling system, messing up with the coolant circulation.
7. Blue or White Smoke from the Exhaust (Oil leak)
In some cases, a bad head gasket can allow engine oil to leak into the combustion chamber, causing blue smoke to come from the exhaust. If both coolant and oil are leaking into the cylinders, you may see a mix of white and blue smoke coming from the tailpipe.
8. External Coolant or Oil Leaks
Sometimes, a failed head gasket causes visible leaks on the outside of the engine. If you see oil or coolant leaking down the side of the engine block, it could indicate a head gasket issue. However, external leaks are less common than internal leaks.
