Blown Head Gasket Symptoms

blown head gasket symptoms


Your engine is overheating and you’re not sure why. What are blown head gasket symptoms? What will a blown head gasket repair cost?

You may have a blown head gasket with many or only one of these symptoms: 

1. Unexplained excessive coolant loss. You keep adding coolant but there is no visible leak.

2. Air bubbles in your radiator coolant overflow bottle when the engine is running and/or visible in the radiator coolant with the cap off and engine running. This is because exhaust gases are being forced into the cooling system.  Caution. It is very dangerous to remove the radiator cap or open up the cooling system unless the engine is cooled down. Doing so can cause you serious personal injury. 

3. Coolant in your oil. Pull the dipstick. If the oil looks like chocolate milk then you likely have a blown head gasket or a cracked engine block. You should also look at the bottom of the oil filler cap to see if it also looks chocolate milkish/foamy.

4. Oil in your coolant. If the coolant appears brownish and possibly foaming this is another sign of a bad head gasket.

5. White exhaust smoke. Coolant is leaking into the cylinders.

6. Unexplained engine overheating. You have checked the obvious things like coolant levels, confirmed no leaks, good thermostat, radiator cap, cooling fans etc but it continues to overheat.

7. You have one or more cylinders that fail a compression pressure or leak down test.

8. A block test determines combustion gasses are present in the coolant system. Most mechanics will have this block test kit and can do this test relatively inexpensively. This test basically checks the coolant for combustion gasses.

9. Reduced power and a rough running engine because compression is reduced and coolant is leaking into the cylinders.

If your car or truck has any of these symptoms, before you attempt repairs yourself or make major engine repair/replace decisions, get a confirmation from a qualified mechanic.  Sometimes there are other problems that can cause some of these symptoms and you may find that your head gasket is ok.

How much to fix a blown head gasket?  Blown head gasket repair costs vary from vehicle to vehicle but usually run in the range of $1200 to $1600 dollars.

However, before you fix that blown head gasket it is important to determine why the head gasket failed to begin with so it doesn’t fail again after you replace it. In addition to the head gasket cost of 1200 to 1600 dollars allow for an additional amount to replace parts that failed causing the overheating in the first place that led to the blown head gasket.

To complicate blown head gasket costs even more, consider that your engine may have overheated so severely that it is not worth repairing. The block may be cracked. Over heated pistons may have swelled and scuffed the cylinder walls. Valve train components may be damaged. Oil that was coolant contaminated may have resulted in  bearing damage due to poor lubrication.

So instead of repairing a blown head gasket maybe you are looking at buying a new engine; or possibly a used engine from a junkyard. Is a rebuilt or remanufactured motor your best option? What are your options if you have a blown headgasket?

So, if you are in that worst case position you are likely asking yourself:  Should I buy a new car? Read  should i buy a new car and  cheap reliable cars for additional insight into answering those questions.



About Richard

I have been a car enthusiast my whole life and have been involved in the car industry for over 25 years. It is my hope that you will get some useful information and enjoyment from this blog.
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