This guide explains how head gaskets fail, what it costs to repair or replace them in Australia and when it might be smarter to sell your car instead of fixing it.
All prices are current as of September 2025 and are based on reputable Australian and international sources.
What Does a Head Gasket Do?
A head gasket is a flat composite or metal gasket that seals the interface between the engine block and the cylinder head.
It contains shaped holes that allow coolant and oil to pass between the block and head while maintaining a gas‑tight seal around each cylinder.
This seal is absolutely critical, when it breaks down, coolant can seep into the cylinders and oil can leak into cooling passages, starving the engine of lubrication and causing steam to jet out of the exhaust.
Signs Your Head Gasket May Be Failing
Because the gasket is hidden deep inside the engine, you often can’t see the leak itself.
However, there are several symptoms to watch out for that hint you might be heading for a head gasket repair or replacement:
- Overheating or temperature spikes – When coolant leaks into the combustion chamber, the engine runs hotter and can overheat quickly.
- White or sweet‑smelling exhaust smoke – Burning coolant produces thick white smoke from the tailpipe. You may also notice a sweet smell.
- Milky or frothy engine oil – Oil contaminated with coolant takes on a creamy, chocolate‑milk appearance.
- Bubbles in the radiator or overflow tank – Combustion gases leaking into the cooling system create continuous bubbles, even when the engine is cool.
- Poor running or misfires – A leaking gasket can allow compression to escape, leading to misfiring and rough running.
If you’ve noticed any of these signs, then take your car to the garage immediately.
Continuing to drive with a potentially damaged head gasket can warp the cylinder head or damage bearings and pistons, all leading to a dramatically increased repair bill.
How Much Does It Cost to Repair or Replace a Head Gasket?
Australian Costs
Repair costs vary widely depending on the vehicle’s make and model, engine configuration, labour rates and how much collateral damage is discovered. In Australia:
- Average replacement cost: The average cost to repair a head gasket is around $1200AUD but this can increase to upwards of $3000AUD according to Australian repair networks like AutoGuru.
- Typical range: We looked at Alpha Cash and the Yellow Pages and found that the average cost to replace a blown head gasket in Australia is between $1,000-$3,200AUD.
- Upper end: If additional parts are needed to replace or even the cylinder head requires machining, costs climb. A ConsumerAffairs’ survey of mechanics found that including parts and labour, individual quotes ranged from US$2,886.50 to US$6,047 ($4,400–$9,200AUD at 2025 exchange rates) for some vehicles!
Head Gasket Repair vs. Replacement
Chemical sealers (temporary fix)
Some companies sell head‑gasket sealers designed to stop small leaks. According to warranty provider Noble Quote, these sealers may provide temporary relief, particularly when the leak is minor and the engine isn’t overheating.
They work by circulating through the cooling system and hardening when they reach the gasket breach. However, sealers rarely offer a permanent solution; they are best used as a last‑ditch option to delay repairs.
Mechanical repair (replacement)
Properly fixing a blown gasket requires removing the cylinder head, machining its sealing surfaces and installing a new gasket.
This is labour‑intensive: mechanics must disassemble the top of the engine, clean mating surfaces, inspect the block, and often replace timing belts, water pumps and thermostats at the same time. Noble Quote notes that professional head‑gasket replacement typically takes 8–20 hours. Because the gasket itself costs only a few hundred dollars, most of your bill is labour.e
Is It Worth Repairing a Blown Head Gasket?
Whether you should repair depends on the value of your car, its overall condition and your budget.
Here at Metro Car Removal, we think repairing is sensible when the vehicle is in good shape and less than 10 years old, however, if the repair cost approaches or exceeds the vehicle’s value, it may be smarter to replace the engine or just scrap your car for cash.
Keep in mind that professional replacement is labour intensive and typically takes 8–20 hours.
If your car has high kilometres, rust or other major faults, spending thousands on a head gasket might not make financial sense.
In those cases, Metro Car Removal or a cash for cars service can take the hassle out of the situation by buying your unwanted car for cash. You’ll avoid repair bills and free up space for a more reliable vehicle.
Why Scrapping with Metro Car Removal Could Be Your Best Bet
At Metro Car Removal, we specialise in helping owners turn their unwanted vehicles into quick cash, often offering a much better deal than sinking money into an expensive catalytic converter replacement.
Benefits at a Glance:
Eco-friendly disposal – we ensure your vehicle is recycled responsibly, components are repurposed properly, and harmful materials are safely managed.
No upfront repair costs – you skip the AU$1,000+ bill entirely.
Immediate value – scrap value can provide fast cash, often more than the net worth of the car post-repair.
Hassle-free service – we arrange pickup, paperwork, and payment on the spot.
Tips to Prevent Head Gasket Failure
Prevention is cheaper than repair. To reduce the risk of gasket failure:
- Maintain the cooling system – Flush and replace coolant every 2–3 years, fix leaks promptly and never run with low coolant.
- Watch the temperature gauge – Pull over if the engine starts to overheat and investigate the cause.
- Replace thermostats and radiator caps when needed – Faulty thermostats can cause overheating.
- Use quality parts – Cheap aftermarket gaskets and bolts may not seal as well or hold up to heat and pressure.
- Service regularly – Routine servicing can spot cooling system issues before they lead to gasket failure.
Metro Car Removal
If you’re needing a new catalytic converter and your car isn’t worth a new one then consider selling your car for cash!
- Free Towing
No need for registration, roadworthy certificates, or running condition, we tow for free from anywhere in Sydney. - Instant Cash Offer
We evaluate your vehicle’s make, model, and condition and present a top‑dollar quote on the spot. - Hassle‑Free Paperwork
We handle ownership transfer and paperwork, so you don’t have to.