HomeAFTERMARKET NEWS5 Most Common Symptoms Of A Failing Head Gasket

5 Most Common Symptoms Of A Failing Head Gasket

Head gaskets are located between the cylinder head and the engine block which work to ensure a perfect seal between the engine block and the cylinder head. Head gaskets help to keep the combustion processes inside the engine thus preventing gases and fluids from coming out of the engine. The gasket helps to keep a steady compression which is key for the engine to run properly and also prevents coolant and oil from mixing between the engine block and the cylinder head.

Below you will find a comprehensive list of the five most common symptoms of a failing head gasket.

  • Contaminated Engine Oil or Coolant: One of the most common symptoms of a failing head gaskets is finding oil inside the cooling system or vice versa. A broken head gasket may allow engine coolant to flow into the oil system, oil can also enter the cooling system. When either or both happen, you will see a foamy and clear sludge stuck to the bottom of the oil filler cap, and you will find the same substance on the oil dipstick when you are checking the oil level. When oil contaminates the cooling system you may find oil deposits at the bottom of the coolant reservoir. You may also find that your coolant has turned into a foamy brownish solution.
  • Pressure Build-up in the Cooling System: If your coolant hoses are swollen when the car is cooling that means that the circuit is building up pressure even when the engine is cold. You may also see bubbles inside your coolant reservoir. Sometimes when head gaskets break, they allow exhaust gases into the coolant system. You can do two easy tests to confirm whether your head gasket is blown. The first and easiest test (not as accurate as the second) is to drive your vehicle for a long period of time allowing the cooling system to reach its operating temperature. You then need to park your car on a levelled surface and leave it overnight letting the coolant cool down. The next day, open your coolant reservoir before starting the engine and listen carefully. If you hear a gassy sound or a short fuzzy sound (like when you open a soda can or a soda bottle) your vehicle’s head gasket is probably starting to fail.
  • The second test is more accurate; you can buy a chemical tester and check for exhaust gases inside your coolant system. These testers are cheap and you only have to remove some coolant from your vehicle. If the liquid inside the tester changes its colour from blue to yellow, then it is confirmed that exhaust gases are present in your cooling system and thus you have a failed head gasket.
  • Coolant Consumption / White Smoke coming out from the Tailpipe or Overheating: The engine’s cooling system is sealed. Unless there is a leak somewhere, the coolant level should not be dropping. If you notice that your coolant level is frequently low and you keep topping it just to find it low once again in one or two days, it is highly probable that the coolant is entering into your engine’s combustion chambers. This is fairly bad for your engine and can cause several problems: overheating, spark plug damage (they get wet), loss of power etc… A severely damaged head gasket may also cause white smoke to come out from your tailpipe as the coolant is burnt inside the combustion chamber and expelled through the tailpipe. Sometimes the engine can’t burn all the coolant that is entering the cylinders, and you may see unburnt coolant coming out from your tailpipe.
  • Engine Knock and Rough Idle: A heavily damaged head gasket can cause a noticeable engine compression loss making the engine stall or run rough. This is more noticeable when the engine is idling.
  • Power Loss: A noticeable compression loss will cause engines to lose power. Heavily damaged head gaskets allow combustion gases to escape the combustion chamber thus reducing the engine’s volumetric efficiency. Pistons will receive less pressure from the air-fuel ignition reducing the engine output. As gases escape from the combustion chamber through the damaged head gasket they will emit -exhaust- hissing sounds.

When should the Head Gasket be Changed?

The head gasket seals the two main parts of your engine (top and bottom) to ensure that the engine is sealed and to keep the coolant separate from the oil. Head gaskets are not an expensive component, but the cost is often associated with the amount of qualified labour it takes to change it on an engine by a mechanic. A failing head gasket can severely damage your engine which will require costly repairs. As soon as you suspect you have a failing head gasket you should be visiting a trustworthy mechanic to perform a health check on your engine.
A vast number of drivers with minor head gasket problems will keep driving their cars until the failure gets bigger to postpone the expense of doing the job. As a mildly damaged head gasket may lead to catastrophic engine failure it is always recommended to replace your head gasket as soon as you can.
As the timing belt/chain must be removed to replace a head gasket – it is often recommended that those are inspected/replaced whilst doing the job in order to save on labour costs.

Mechanic inspecting the engine bay of a vehicle

About BGA (BG Automotive):

BGA is an Automotive Aftermarket parts supplier, celebrating over 90 years of OE manufacturing heritage as the aftermarket division of the largest privately owned OE supplier, 4BG Group, established in 1929.

BGA focuses on providing one of the largest ranges of high quality, competitively priced parts in the aftermarket containing Auxiliary Drive, Camtrain, Cooling, Gaskets, Lubrication, Power Steering, Steering & Suspension, Timing Belt Kits, Timing Chain Kits and Transmission.


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