How To Test For A Blown Head Gasket (1997-2004 4.2L V6 Ford F150)

Testing the head gaskets to see if they've failed isn't difficult at all, and it's something you can do easily and quickly yourself.

So, if your 4.2L Ford F150 (F250) has suffered severe overheating and you suspect a blown head gasket, this tutorial will explain the four most common tests for confirming a blown head gasket.

You can find this tutorial in Spanish here: Cómo Probar El Empaque de Cabeza (4.2L Ford F150, E150, E250) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 4.2L V6 Ford F150: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005.
• 4.2L V6 Ford F250: 1998.

E-SERIES VANS: The head gasket test tutorial for the 1997-2003 4.2L V6 Ford E150/E250 vans can be found here:

• How To Test Engine Compression (1997-2003 4.2L V6 Ford E150, E250) (at: troubleshootmyvehicle.com)

Symptoms Of A Blown Head Gasket

In the vast majority of cases a blown head gasket is the end-result of the engine severely overheating.

There are several symptoms and if the head gasket is blown on your 4.2L Ford F150 (F250), you'll definitely see at least one or two of them:

1. Overheating.
2. Oil mixed with coolant (which looks like 'coffee with too much cream').
3. White smoke coming out of the tail-pipe.
4. Engine cranks, but does not start.
5. No compression on two side by side cylinders.

Let's get testing.

TEST 1: Motor Oil Looks Like 'Coffee With Too Much Creamer'

As you're already aware, part of the head gasket's job is to keep the oil and coolant (flowing thru' the oil and coolant passages in the block and heads) from mixing together.

So, when a head gasket or gaskets get blown, the most common end result is coolant mixing with the engine oil.

Since checking for this is one of the easiest test to do, we'll start with it first.

These are the steps:

1. 1

   Open the hood of your 4.2L Ford pickup.

2. 2

   Pull out the engine oil dipstick.

3. 3

   Check the color of the oil sticking to the dipstick.

4. 4

   You'll see one of two things:
   
   1.) The color of the oil will be a milky white color.
   
   2.) The color of the oil will be its normal color.

Let's take a look at your test results:

CASE 1: The engine oil was a milky white color. This tells you that the coolant is mixing with the Oil and that you do have a blown head gasket on your hands.

CASE 2: The engine oil was its normal color. This doesn't confirm anything just yet. You'll need to go to the next test to make sure. Go to: TEST 2: Coolant Shooting Out Of Radiator.

TEST 2: Coolant Shooting Out Of Radiator

Another important job the head gaskets accomplish is to keep the combustion pressures and exhaust gases within the cylinder and from exiting into the coolant and oil passages in the block.

So, when a head gasket gets blown, the second most common end-result is compression/combustion pressures and gases escaping into the block coolant passages and into cooling system (by cooling system I mean the radiator).

This is another very easy test to do and these are the steps:

1. 1

   Remove the radiator cap from the radiator.
   
   The engine should be completely cold before you open the radiator cap. Opening the radiator cap on a hot engine can spray hot coolant all over you and severely burn you.

2. 2

   Check the coolant level. If the coolant level is low, top it off before proceeding.
   
   You don't have to add coolant, just add water.

3. 3

   Stand at a safe distance from the engine but within view of the radiator.

4. 4

   Have your helper crank the engine as you observe the radiator's neck.

5. 5

   You'll see one of two results:
   
   1.) The coolant shoots out violently when the engine was cranked.
   
   2.) The coolant was not disturbed at all.

Let's take a look at your test results:

CASE 1: The coolant shot out of the radiator. This confirms beyond a shadow of a doubt that you do have a blown head gasket on your hands.

CASE 2: The coolant DID NOT shoot out of the radiator. So far so good. In TEST 1, you confirmed that coolant isn't mixing with the engine oil. In this test, you have confirmed that no exhaust gases are escaping thru' the radiator...

If you still think that you do have a blown head gasket on your 4.2L Ford F150 (F250), read the next test. Go to: TEST 3: Engine Compression Test.