How to Test for a Blown Head Gasket (7 Easy Steps)

There are few problems more noticeable than a blown head gasket. Not only can they be expensive and time-consuming to replace, but they have also been known to be abandoned.

But how do you know if you have a blown head gasket or if the problem is something else? We’ll explain everything you need to know to test a blown head gasket in this comprehensive guide.

What is the head gasket used for?

Your head gasket sits between the head of your engine and the combustion chamber and keeps all the different fluids in the correct channels. It may seem like a fairly simple job, but it is so close to the combustion chamber that it is exposed to a lot of force and movement.

Additionally, if the seals begin to fail, you will run into a litany of problems that can further damage the engine. It may seem like a simple component, but it has an essential job.

How to test the head gasket

The two easiest ways to test the head gasket are to check the oil and exhaust. But although these are the easiest ways, they are not the only things you can check to confirm. Below, we highlight the seven most effective ways to test for a blown head gasket:

1. Check your engine oil

One of the easiest and most effective ways to check if you have a blown head gasket is to take a look at your engine oil. You can check it by pulling on the dipstick, but if you’re about to need an oil change, it’s much more efficient to drain it from the pan and watch.

Engine oil mixed with coolant indicates a blown head gasket. You will know it is mixed if you see a milky color in your oil instead of the brown or black color of the used oil. The more coolant, the milkier the color will be.

2. Check your exhaust

If you look at your exhaust and there is a lot more smoke than normal, it may mean you have a blown head gasket. However, there are a few things you should keep in mind when diagnosing excess exhaust.

First, as the outside temperature drops, you can expect more exhaust fumes than in warmer months. This is completely normal and does not indicate a blown head gasket.

Second, you should look for excessive white smoke if you have a blown head gasket, as this is the color that will burn coolant if it enters the combustion chamber. Finally, you always have to have excess smoke for the problem to be a blown head gasket.

If the amount of exhaust smoke fluctuates after warm-up or on different days, the problem is probably not a blown head gasket.

RELATED: 6 Causes of White Car Smoke Coming from the Exhaust

3. Check your spark plugs

A telltale sign of a blown head gasket is oil or coolant on the spark plugs. While it’s not as easy to see as oil or exhaust, it’s a sure way to diagnose the problem.

Simply take out your spark plugs and take a close look at each one. If you see oil or coolant residue on the tip of the spark plug, you have a problem, and it is probably a blown head gasket.

4. Check the radiator

There are several things you can look for when checking your radiator. First, a blown head gasket will let air into the cooling system and cause the radiator to have a bubbly mixture.

Additionally, oil and fuel could mix in the system. If this happens, you will have a milky-colored mixture when you check the radiator.

5. Check your coolant

Your coolant is a sealed system, meaning what you put into your system should stay there. And while levels may fluctuate slightly due to differences in temperature and pressure, for the most part, they should stay the same.

So if you find that you need to keep adding coolant to the system but there is no visible leak, chances are your coolant is going somewhere it shouldn’t be inside your engine. If it has excess smoke, it enters the combustion chamber, and if it has milky-colored oil, it enters the oil channels.

In addition, all of your oil can change color if it mixes in the refrigeration liquid, if the refrigeration liquid is already in the refrigeration liquid reserve, you should note a masseuse/latitude color that indicates that you have a problem. .

If smoke comes out of the coolant reservoir when you close the coolant cap, it could also mean that compression is entering the cooling system. This can also be tested with an exhaust tester.

6. Do a compression test

Although this is one of the most complicated tests to run, it is also one of the most effective. You will need some specialized tools to do the job and you will also need to remove the spark plugs. When you remove the spark plugs, be sure to check them for any coolant or oil residue.

You will notice a drop in compression in the affected combustion chamber if you have a blown head gasket. This is because the cylinder can never seal completely and excess pressure will escape.

However, small leaks can be very difficult to notice with this method.

7. Check for leaks

While most people know that a blown head gasket can send fluids to other parts of your engine, it is less known that blown head gaskets can cause external leaks.

It all depends on where the leak is. If it is toward the outside of the head gasket, the fluid will flow out of the engine instead of through different passages.

This can cause smoke to come out of your engine if it builds up and burns before hitting the ground. Or, if you hit the ground, you should notice puddles of liquid forming under your vehicle.

This fluid could be coolant or oil, and the only way to diagnose it as a badhead gasket is to trace it back to the source of the leak. If you find that it is coming from the head gasket, you have found your problem!

ADDITIONAL TIP

The easiest way to determine if there is a coolant leak into the oil or combustion chambers is to use a cooling system pressure tool.

Simply plug it in and let it pressurize for 10 minutes. The pressure must be stable because the cooling system must be airtight. If the pressure drops, it mainly leaks into the oil or the cylinders.

Remove the spark plugs and check for signs of coolant in the cylinders. Also, check the dipstick for signs of coolant in the oil pan.

You can use this tool for this purpose: