How To Test For A Blown Head Gasket (1991-2000 3.0L Caravan, Grand Caravan, Voyager, Grand Voyager)

Checking for a blown head gasket is not that hard. In this tutorial, I'm gonna show you the four tests that you can do to figure it out.

You can quickly do two of these tests without any tools. The other two tests are the compression test (requiring a compression tester) and a block test (requiring a combustion leak detector).

Once you've completed these tests, you'll know if the 3.0L V6 engine in your car has a blown head gasket.

APPLIES TO: This tutorial applies to the following vehicles:

• 3.0L Chrysler Voyager: 1995.
• 3.0L Dodge Caravan: 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000.
• 3.0L Dodge Grand Caravan: 1992, 1993, 1994, 1995, 1996, 1997, 1988, 1999, 2000.
• 3.0L Plymouth Voyager: 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000.
• 3.0L Plymouth Grand Voyager: 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000.

Symptoms Of A Blown Head Gasket

When one or both head gaskets fail, you'll usually see one of two problems:

• The engine cranks but doesn't start.
• The engine starts but then overheats in no time for no good reason.

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: The engine starts to overheat within minutes of starting it.
• White Smoke: You may see white smoke coming out of the tailpipe and it smells like anti-freeze being cooked.
• Engine Oil The Color Of Coffee With Too Much Creamer: The engine oil is thick and a tan to off-white color (mixed with coolant).

What Does A Head Gasket Do?

A head gasket is a critical gasket in your engine. It sits between the engine block and the cylinder head. Its job is to seal the combustion process and keep the coolant and oil separate as they travel through the engine block and cylinder head.

The main roles of a head gasket are:

• Sealing the combustion chamber to ensure maximum compression and avoid leakage of coolant or oil into the cylinders.
• Keeping the coolant and oil separate as they move through passages in the engine block and cylinder head.

A head gasket can fail due to several reasons:

• Overheating: If the engine overheats, it can cause the head to warp, leading to a failure in the gasket's seal.
• Wear and Tear: Over time, the stress of the engine's heat and pressure can cause the gasket to degrade.
• Improper Installation: If a head gasket isn't installed correctly, it can fail prematurely.
• Engine Issues: Problems like detonation or pre-ignition inside the combustion chamber can damage the gasket.

In the 3.0L V6 engine, the cylinders are set up in a 'V' shape, creating two banks (groups) of cylinders. That's why there are two cylinder heads, one for each bank.

Since there are two separate cylinder heads, there is a head gasket for each one. Both head gaskets have the same job: sealing the combustion chambers, preventing oil and coolant from mixing together, and keeping the oil and coolant passages in each half of the engine flowing properly.

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

When one or both head gaskets fail, a common issue you might notice is coolant mixing with the engine oil. This happens because the head gasket, which is supposed to keep the oil and coolant separate inside the engine, loses its ability to seal properly. As a result, the coolant can start leaking into the engine's oil system and into the oil pan.

This mixture gives the engine oil a milky-white color, similar to a 'coffee with a lot of creamer'. This milky-white appearance is a clear sign that one or both head gaskets are blown.

So, for our first test, we'll look at the condition of the engine oil and see if it's a milky-white color.

Let's get started:

1. 1

   Open the hood.

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 see what your test result means:

CASE 1: The engine oil looks like 'coffee with too much creamer'. This confirms that one or both 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

Another common problem with a blown head gasket is it allowing engine compression (or combustion pressures) to escape into the cooling system.

This type of failure causes the cooling system to over-pressurize. This can lead to several issues like coolant being forced out of the overflow tank and the engine overheating. It can also potentially damage the cooling system components like the radiator or hoses.

To check if this issue is happening, we can crank the engine with the radiator cap off. If one or both head gaskets are blown and letting compression or combustion gases into the cooling system, the coolant will be pushed out of the radiator forcefully (while the engine is cranking).

But, if the head gaskets are OK (and not allowing these gases to enter the cooling system), the coolant in the radiator will stay still and undisturbed.

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, let it cool down completely before removing the radiator cap!

These are the test steps:

1. 1

   Remove the radiator cap from the radiator.

2. 2

   Check the coolant level and add water if necessary.

3. 3

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

4. 4

   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 the head gasket is 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, your next step is: TEST 3: Engine Compression Test.

If the engine starts and runs but overheats, your next test is: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).