Tech Tip: Blown Head Gasket Symptoms, Causes and Fixes

Early detection prevents costly and time-consuming repairs

Head gasket issues are BY FAR the #1 problem our support team talks to customers about every day.

Since the head gasket has the most critical sealing job in the engine — to seal and protect the cylinders from coolant or engine oil infiltration to ensure maximum compression —  a blown head gasket can be crippling. When a head gasket leak is detected early, it often can be repaired chemically before it grows into a $1,500 to $3,000 problem.

How to spot a blown head gasket

Here’s a short list of customer complaints that are symptoms or signs of a blown head gasket:

  • A strong, sweet smell of heated coolant.
  • Low coolant level in the coolant reservoir, without visible leaks.
  • Bubble formations in cooling system.
  • Reduced power or problems with idling and acceleration.
  • Engine overheating.
  • White exhaust smoke.
  • Engine misfiring.
  • Milky discoloration in oil (check the oil cap).

Options for fixing a blown head gasket

For many customers, especially those with older vehicles, the cost of a physical head gasket replacement or engine rebuild can be more than the car is worth. That’s why we created the chemical head gasket repair category of products (yes, we created the entire category, and other followed), and now offers three easy-to-use permanent head gasket repair solutions.

Here’s some guidance on which product to recommend.

1) Good.

Bar’s Leaks Head Gasket Repair (p/n #1100) has the lowest purchase price of the three options. It contains a blend of aramid and refractory fibers to provide the strength of a bulletproof vest and the heat resistance of fireproof clothing. As these particles penetrate a crack or the blown head gasket area, they lock together and bond, forming a hard, permanent ceramic-type seal. This product is applied in a multi-step process that includes draining the coolant system. It is not compatible with antifreeze, and must only be added to cooling system after all antifreeze has been removed. It can be used in vehicles that can idle for at least 20 minutes without overheating.

2) Better.

Bar’s Leaks Head Gasket Fix (p/n #1111) contains a combination of antifreeze-compatible sodium silicate sealing liquid and various gasket-sealing particles that penetrate gaps and cracks and harden to permanently stop leaks. The extreme heat inside the combustion chamber (5000°F) works as a catalyst to permanently harden the material to make it stronger than the original head gasket itself. Installation is as easy as pouring the product into the cooling system and following the idling instructions. No draining of the coolant system is required. This product is effective in vehicles that can idle for at least 20 minutes without overheating.

3) Best.

head gasket repair

Bar’s Leaks Professional Carbon Fiber Blown Head Gasket Repair (p/n #HG-1) is the strongest antifreeze-compatible solution on the market, period. It penetrates a leaking, damaged or blown head gasket, drying to form a seal that’s actually stronger than the original head gasket itself. It’s the best formula to also stop all other coolant leaks in plastic, cast iron, copper and aluminum radiators, heater cores, freeze plugs, gaskets, intake manifolds, cylinder heads and engine blocks. The special formulation also contains Xtreme Cool™, which stops overheating and reduces water temperature. No draining of the coolant system is required, and installation is easy – just pour into coolant system and follow idling instructions on the bottle. This product can be used if the vehicle can idle for 15 minutes without overheating.

But don’t just take our word for it: for an unbiased product review of Professional Carbon Fiber Blown Head Gasket Repair (HG-1), check out the customer video at Customers who purchase by September 30, 2018, can receive a $10 rebate. Visit the online Rewards Center at for details.

Causes of a blown head gasket

Customers will often ask what could have caused their head gasket to fail. Head gaskets are put under enormous stress during engine operation, and failure may be caused by any of the following factors:

  • Mechanical Forces. The nature of the detonations in an engine creates huge amounts of energy, or pressure, every time the cylinders fire. Over time, these forces stress head gaskets and can eventually lead to cracks and leaks.
  • Heat. An engine creates large amounts of heat under operation. A difference in thermal expansion rates between the engine block and head mean the head gasket in between is subjected to high thermal and mechanical stresses that slowly wear the gasket down.
  • Vibration. Natural vibrations from the engine and those created as the vehicle is driven down the road also fatigue the head gasket over time. Head bolts, which keep the head gasket sandwiched between the block and head, can start to weaken, break or stretch (and possibly warp) to allow increased friction and vibration wear. A poor design that lacks sufficient clamping force from the head bolts can also cause failure.
  • Overheating. Allowing the coolant level to run low can cause damage to a head gasket. When coolant isn’t available to pull engine heat from the block and heads, the extra heat can cause expansion on the head gasket, which often results in a blown head gasket.

Head gasket problems can sideline your car – and your wallet – if left untreated for too long. At the first signs of head gasket leaks or problems, assess your situation immediately. If you catch the leak early enough, before it becomes too severe, there’s no need for your life to get turned upside down by an expensive repair.

Have questions or need help? Give us a call at 800-345-6572, or contact us via the web and we’ll get back to you right away.

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