Can you still drive a car with a bad head gasket?

Short answer: in most cases, you should not drive a car with a bad head gasket. If you suspect a failure, arrange a tow to a qualified mechanic to avoid risking major engine damage.

A head gasket seals the relationship between the engine block and cylinder head, keeping coolant, oil, and combustion pressures in their designated paths. When it fails, coolant can contaminate oil, oil can contaminate the cooling system, and combustion pressures can escape, often leading to overheating. This article outlines why driving with a suspected head gasket issue is dangerous, common warning signs, and the safest steps to take.

Immediate risks of driving with a failing head gasket

These are the most common consequences you could face if you continue to drive while the gasket is failing. They can escalate quickly and lead to expensive repairs.

• Engine overheating due to coolant loss or improper cooling flow


• Coolant leaks or steam from under the hood indicating loss of cooling pressure


• Oil contamination—milky or frothy oil that spoils lubrication


• Loss of compression, misfires, rough running, and reduced power


• Warping of the cylinder head or damage to the engine block from sustained heat


• Hydro-lock risk if coolant enters a combustion chamber


• Catastrophic engine failure that can render the vehicle inoperable

Over the long term, continuing to drive with these conditions often worsens damage and raises repair costs dramatically. The safest course is to stop driving and seek professional diagnosis and repair.

Common warning signs you may have a head gasket problem

Not every symptom alone proves a gasket failure, but multiple concurrent signs strongly suggest an issue and warrant a professional check.

• Persistent or rapidly rising engine temperature and frequent overheating


• Unexplained coolant loss with no visible external leaks


• Oil that appears milky or emulsified, indicating coolant contamination


• White exhaust smoke or a sweet coolant-like odor from the exhaust


• Loss of power, rough idle, or misfires without an obvious cause


• Bubbles in the radiator or coolant reservoir when the system is under pressure


• Coolant or oil around the head gasket area on inspection

If you notice several of these symptoms together, do not delay diagnosis. A mechanic can perform tests to confirm gasket integrity and rule out other issues.

What to do if you suspect a head gasket problem

Taking prompt, cautious steps can minimize damage and help ensure you get a proper repair assessment.

• Safely pull over and stop the vehicle to prevent further overheating or damage


• Do not drive the car to a shop; arrange towing or roadside assistance


• If safe, check under the hood for obvious coolant leaks and monitor the temperature gauge


• Avoid removing the radiator cap when the engine is hot to prevent scalding or system damage


• Have the car inspected by a qualified mechanic who can perform compression/leak-down tests and a chemical block test


• Discuss repair options and costs, which may include replacing the head gasket and potentially resurfacing the head or replacing related components

In most cases, towing the vehicle to a shop is the prudent choice. Driving can quickly turn a gasket issue into a far more expensive engine repair.

Is a brief, careful drive ever acceptable?

In rare emergencies, some drivers consider moving a car a short distance to a nearby shop. This is not advised and should only be considered if there is no safer alternative, and only after evaluating the risk of severe damage. If attempted, keep speeds extremely low, monitor temperature closely, and seek professional service as soon as possible.

Even with caution, the safest course remains to avoid driving and arrange professional towing to a repair facility.

Summary

A bad head gasket is a serious engine issue that can lead to overheating, oil contamination, loss of power, and permanent damage. The responsible choice is to stop driving, avoid attempting to reach a shop yourself, and arrange a tow for a proper diagnosis and repair. Early attention can prevent costly repairs and extend the life of the engine.

What happens if a head gasket goes while driving?

Driving with a blown head gasket can lead to severe engine damage, including overheating, loss of power, and internal component failure. It can also cause the engine block or cylinder head to warp or crack, leading to costly repairs or the need for an engine replacement. It is strongly recommended to stop driving the vehicle immediately if you suspect a blown head gasket to prevent further damage.
 
You can watch this video to learn what happens to your car when you drive with a blown head gasket: 1mMercie J Auto Care, llcYouTube · Jun 7, 2021
What happens when you drive with a blown head gasket

• Engine overheating: A blown head gasket can allow hot combustion gases to leak into the cooling system, causing the engine to overheat rapidly. 
• Loss of power and poor performance: The engine will lose compression, leading to a noticeable drop in power and reduced fuel efficiency. 
• Contamination of fluids: The gasket is supposed to keep oil and coolant separate. When it fails, oil can mix with coolant, creating a milky substance, and coolant can leak into the oil or combustion chambers. 
• Internal damage:
  • Erosion: Combustion pressure leaking into the radiator can create acid that degrades cooling system components like the water pump and radiator. 
  • Component damage: Coolant entering the cylinders can cause broken or warped pistons and valves. 
  • Catalytic converter damage: Coolant passing through the exhaust system can damage the catalytic converter. 
• Increased risk of severe failure: Continuing to drive can cause more extensive damage to the cylinder head and engine block, making the damage irreversible and requiring more expensive repairs or a complete engine replacement. 

What to do if you suspect a blown head gasket

1. Pull over and stop driving immediately: Do not continue to drive the vehicle to prevent further damage. 
2. Allow the engine to cool down: This is especially important if the engine has been overheating. 
3. Check the coolant and oil: Look for signs of mixing, such as a milky residue on the oil cap or milky coolant in the reservoir. 
4. Schedule a diagnostic: Have the vehicle towed to a mechanic for a professional diagnosis and repair as soon as possible. 

Is it worth fixing a car with a blown head gasket?

Whether a blown head gasket is worth fixing depends on the car's value and the extent of the damage. It's likely worth repairing if the vehicle is in good overall condition and the repair cost is significantly less than the car's market value. However, it may not be worth the cost if the repair will exceed the car's value or if the engine has sustained severe damage, potentially making a new-to-you car a better investment. 
This video demonstrates how to diagnose a blown head gasket and its potential consequences: 54sDonutYouTube · Sep 30, 2020
When to fix a blown head gasket

• Your car is in good condition and valuable: If the vehicle has low mileage, is reliable, and you plan to keep it for a long time, the cost of a head gasket replacement can be justified. 
• The repair cost is significantly less than the car's value: A common rule of thumb is that the repair cost should be less than half the vehicle's worth. 
• The damage is limited: The head gasket failure hasn't caused other major engine issues like a warped or cracked block. 

When it may not be worth fixing

• The repair cost is close to or exceeds the car's value: If the repair is expensive and the vehicle is older or has high mileage, you might be better off selling the car for parts or buying a different one. 
• There is severe engine damage: A blown head gasket can sometimes lead to more serious problems like a damaged engine block or head, which can make the repair too expensive and not worth the cost. 
• The vehicle has other major issues: If the car has multiple significant problems, a head gasket repair may not be a wise investment. 

Other options to consider

• DIY sealers: For less valuable vehicles, a DIY head gasket sealer can be a temporary or potentially permanent low-cost solution to buy some time or prevent further damage, but a proper repair may still be needed later. 
• Replacing the engine: In some cases, it may be more cost-effective to replace the entire engine rather than just the head gasket, especially if the head itself is damaged. 

You can watch this video to learn about a temporary fix for a blown head gasket: 58sChrisFixYouTube · Oct 18, 2021

What are the first signs of a blown head gasket?

The first signs of a blown head gasket include engine overheating, white smoke from the exhaust, and milky-colored oil. Other initial indicators are unexplained coolant loss, bubbles in the radiator or coolant reservoir, and rough engine performance. 
Engine and exhaust symptoms

• Engine overheating: The engine may run hotter than normal, with the temperature gauge climbing into the red. 
• White smoke: You may see thick, white smoke or steam coming from the exhaust, especially when starting the car or at idle. 
• Bubbling in the coolant: Bubbles may appear in the radiator or the coolant overflow tank. 

Fluid and oil symptoms

• Milky oil: The engine oil may look milky or have a frothy, "chocolate milk" appearance. 
• Unexplained coolant loss: Your coolant level may drop over time with no visible external leaks on the ground or under the car. 
• Oil in the coolant: You might see oil residue floating in the coolant reservoir or radiator. 

Performance symptoms

• Loss of power: The car may feel sluggish, have reduced acceleration, or misfire. 
• Rough idling: The engine may run roughly or idle poorly. 

What to do
If you notice any of these signs, it is best to have your vehicle inspected by a professional to avoid more serious engine damage.

How long can you drive with a bad head gasket?

You should not drive with a blown head gasket, but if you must, limit the distance to a very short trip, like to a repair shop. Driving with a bad head gasket can cause serious engine damage, including overheating, mixing of oil and coolant, and catastrophic failure, leading to much more expensive repairs. Keep coolant topped up and monitor your engine temperature constantly on the short drive, or avoid driving altogether and have the car towed. 
Why you should not drive with a blown head gasket

• Overheating: Coolant can escape, causing the engine to rapidly overheat and potentially warp the cylinder head or crack the engine block. 
• Oil and coolant mixing: Leaking combustion pressure and mixed oil/coolant can dilute the oil, reducing lubrication and causing damage to engine bearings. 
• Engine seizure: A seized engine is a serious consequence, making repair more costly or even impossible. 
• Corrosion: Combustion gases entering the cooling system can create acid that corrodes engine components. 
• Loss of power: A blown head gasket can lead to a loss of compression, resulting in a significant drop in engine power. 

How to drive with a blown head gasket (only if absolutely necessary)

• Limit to a short trip: Only drive to the nearest repair shop. Avoid highways and long distances. 
• Check coolant frequently: Check your coolant level often and top it off as needed. 
• Monitor temperature: Keep a close eye on your temperature gauge to prevent overheating. 
• Consider towing: The safest option is to have the vehicle towed to a mechanic to avoid further damage.