How To Test A Blown Head Gasket (3.3L V6 Buick, Oldsmobile)

Testing for a blown head gasket is not hard. In this tutorial, I'm going to explain the 4 different tests that you can perform so that you can find out if you have a blown head gasket on your hands or not.

All of the tests are explained in a step-by-step manner and in plain English.

ES You can find this tutorial in Spanish here: Cómo Probar Los Empaques De Cabeza (1989-1993 3.3L V6 Buick, Oldsmobile) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 3.3L V6 Buick Century: 1989, 1990, 1991, 1992, 1993.
• 3.3L V6 Buick Skylark: 1989, 1990, 1991, 1992, 1993.
• 3.3L V6 Oldsmobile Achieva: 1992, 1993.
• 3.3L V6 Oldsmobile Calais: 1989, 1990, 1991.
• 3.3L V6 Oldsmobile Cutlass Ciera: 1989, 1990, 1991, 1992, 1993.

Symptoms Of A Blown Head Gasket

Over the years that I've been working on cars, I've noticed that blown head gasket problems usually fall in one of two categories.

Either the blown head gasket problem will cause the engine to crank but not start or the engine starts, runs, but overheats within minutes.

If the engine in your vehicle starts and runs and the head gasket is blown, you'll see one or more of the following symptoms:

• The engine overheats.
• White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
• The engine oil is thick and a tan to off-white color (mixed with coolant).

TEST 1: Oil The Color Of Coffee With Too Much Creamer

The very first thing that we're going to do, is to check the color and viscosity of the engine oil that is sticking to the engine oil level dipstick.

What we're looking for, is to see if the oil sticking to the dipstick looks like coffee with too much creamer.

If the engine oil looks milky white and is a very thick viscosity, then you can conclude that one of the head gaskets is blown.

If the engine oil looks normal, then the next step is to go to TEST 2.

Let's get started:

1. 1

   Open the hood on your 3.3L V6 Buick (Oldsmobile).

2. 2

   Pull out the engine's oil dipstick.

3. 3

   Check the color of the oil and how thick it is.

4. 4

   You'll see one of two things:
   
   1.) The oil on the dipstick is a creamy, off-white color and is thick as syrup.
   
   2.) The oil is its normal color and viscosity.

Let's examine your test result:

CASE 1: The engine oil looks like 'coffee with too much creamer'. This confirms that one or both of the head gaskets are blown.

CASE 2: The color of the engine oil is normal. This is the correct and expected test result.

The next step is to check to see if compression/exhaust gases are leaking into the cooling system. Go to: TEST 2: Exhaust Gases Shooting Out Of The Radiator.

TEST 2: Exhaust Gases Shooting Out Of The Radiator

If you've reached this point, then the engine oil sticking to the dipstick looks normal. In this test section, we're going to remove the radiator cap and then crank the engine.

If the coolant gets shot out of the radiator, then you can conclude that one or both of the head gaskets are blown.

Now, if the coolant remains undisturbed in the radiator, as you crank the engine, then the engine has passed this test with flying colors. Your next step is to go to TEST 3.

CAUTION: Do not remove the radiator cap from the radiator if the engine is hot. If the engine has been running for any length of time, then let it cool down completely before removing the radiator cap!

These are the test steps:

1. 1

   Remove the radiator cap from the radiator.
   
   If the radiator is not full, then top it off with water.

2. 2

   Have your helper to crank the engine, while you stand at a safe distance from the open radiator.

3. 3

   You'll see one of two results:
   
   1.) The water or coolant inside the radiator will shoot up and out of the now open radiator.
   
   2.) The coolant will not be disturbed. In other words, cranking the engine will have no effect on the level of the water or coolant in the radiator.

Let's examine your test result:

CASE 1: The coolant bubbled out or shot out from the radiator as the engine was cranked. This result confirms that one or both of the head gaskets are blown.

CASE 2: The coolant DID NOT bubble out NOR shoot out from the radiator as the engine was cranked. This is the correct test result.

If the engine doesn't start, in your 3.3L V6 Buick (Oldsmobile), go to: TEST 3: Cylinder Compression Test.

If the engine, in your 3.3L V6 Buick (Oldsmobile), runs but overheats, go to: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).

TEST 3: Cylinder Compression Test

There are times that one of the head gaskets will burn between two side by side cylinders (the photo at the beginning of this tutorial shows this type of failure).

When this happens, those two side-by-side cylinders will have 0 compression and will misfire.

In most cases, the engine will start and run but will run very rough since it's only working with four cylinders.

Usually, although the engine is running very rough (misfiring), the engine will not overheat.

The only way to find out if the head gasket has burned in a location between two side-by-side cylinders is to do a compression test.

NOTE: You can find the engine compression test explained in a bit more detail in this step-by-step tutorial: How To Test Engine Compression (3.3L V6 Buick, Oldsmobile).

These are the test steps:

1. 1

   Disconnect the ignition coil from its electrical connector. This is will disable the ignition system and is an important safety precaution.

2. 2

   Disconnect the fuel pump relay from its electrical connector.

3. 3

   Disconnect all spark plug wires (from their spark plugs).

4. 4

   Remove all of the spark plugs.

5. 5

   Thread in the compression tester by hand, on the first spark plug hole you're gonna' start with.
   
   Do not use any tools to tighten the compression tester. Hand tightening the compression tester is more than enough to get the proper results.

6. 6

   Have a helper crank the engine as you observe the compression tester.

7. 7

   When the gauge's needle stops climbing, have your assistant stop cranking the engine.

8. 8

   Write down the reading and what cylinder it belongs to on a piece of paper (you can use the illustration above to help you identify the cylinder).

9. 9

   Remove the compression tester and repeat the above steps in the remaining cylinders.

OK, let's take a look at what your results mean:

CASE 1: All cylinder compression readings where normal. This is the correct test result and it confirms that the head gaskets are OK (not burned at a spot between two side-by-side cylinders).

If you still suspect a blown head gasket, go to: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).

CASE 2: Two side by side cylinders had 0 PSI compression. This test result confirms that the head gasket is burned thru' at the point between those two cylinders. You'll need to replace both head gaskets.

TEST 4: Using A Chemical Block Tester (Combustion Leak Tester)

For the most part, the 3 previous tests can easily and inexpensively confirm that one or both head gaskets are blown.

But in some cases, the previous 3 tests simply don't pinpoint the problem to a blown head gasket, even though the engine does have a head gasket failure issue.

In these cases a block test has to be performed. And a block test involves using a chemical combustion leak detector to confirm that one or both of the head gaskets have failed.

This is how the combustion leak detector test (block test) works:

• The combustion leak detector tester is filled with a blue liquid chemical (see photo above).
• The radiator cap is removed (you may have to drain some of the coolant in the radiator since this tool needs to ‘gulp’ some of the air inside the radiator).
• The engine is started.
• The tester is then placed on the open radiator neck.
• The rubber bellow is then squeezed to suck in the air up through the two fluid-filled chambers. As the air bubbles up through the fluid, it will cause a chemical reaction.
• If the blue chemical turns yellow (for gasoline engines), then combustion gases are entering the radiator. This in turn confirms a blown head gasket, a cracked block, or a cracked cylinder head issue.
• If the blue chemical doesn't change color, then you can conclude that you don't have a blown head gasket, a cracked block, or cracked cylinder head issue.

You can shop for a block tester here:

More 3.3L V6 Buick, Oldsmobile Tutorials

You can find a complete list of 3.3L V6 Buick and Oldsmobile tutorials in this index:

• GM 3.3L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test Engine Compression Test (3.3L V6 Buick, Oldsmobile).
• What Does The MAF Sensor Do? (3.3L V6 Buick, Oldsmobile) (3.3L V6 Buick, Oldsmobile).
• How To Test The Throttle Position Sensor (3.3L V6 Buick, Oldsmobile).
• How To Test The MAF Sensor (3.3L V6 Buick, Oldsmobile).