How To Test For A Blown Head Gasket (1997-2010 4.6L, 5.4L Ford F150, F250, And F350)

There are four different tests that you can do to determine if you have a blown head gasket on your Ford F150, F250, or F350 pickup.

In this tutorial, I'm gonna explain each one in detail. Two of these four tests don't require any tools whatsoever and can be done within a few minutes.

Now, hopefully, you don't have a blown head gasket on your pickup, but if you suspect you do, this tutorial will help you get to the bottom of it.

APPLIES TO: This tutorial applies to the following vehicles:

• 4.6L Ford F150: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010.
• 5.4L Ford F250 Light Duty: 1997, 1998, 1999, 2000.
• 5.4L Ford F250 Super Duty: 1997, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010.
• 5.4L Ford F350 Super Duty: 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010.

E-Series Vans: You can find the blown head gasket test for the E-Series vans here:

• How To Test For A Blown Head Gasket (1997-2003 4.6L, 5.4L V8 Ford E150, E250, E350) (at: troubleshootmyvehicle.com).

Important Tips And Suggestions

TIP 1: You should never open the coolant expansion tank if the engine has been running for any length of time.

The coolant will be under pressure and opening the coolant expansion tank can cause hot coolant to scald you as it coming spraying out.

Be careful, take all necessary safety precautions. Think safety all of the time.

TIP 2: When performing a compression test, you'll need a helper. You can keep your eyes on the compression gauge as your helper cranks the engine this way.

As you set up the compression gauge (in the spark plug hole), have your helper wait outside of the vehicle, till you're done and you're safe distance from the engine.

Once you have recorded the compression value, have your helper get out of the vehicle and wait outside (of it) till you have finished setting up the compression gauge in the next spark plug hole.

Symptoms Of A Blown Head Gasket

The most common cause of a blown head gasket is that the engine overheated. When this happens, for the most part, you're gonna see one of two types of problems when your pickup suffers a blown head gasket issue:

• An engine no-start problem: The head gasket or head gaskets' failure is causing the engine to not start.
• The engine starts and runs, but overheats within minutes: In this case, the head gasket failure isn't catastrophic enough for the engine to not start. Unfortunately, even tho the engine starts and runs, it overheats within minutes.

Here are a few more symptoms you'll see:

• Your Ford pickup is overheating. You know it's not the fan (or fan clutch) or thermostat.
• White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
• The engine won't start.
  • You've already verified it's not an ignition system problem (you've confirmed all 8 spark plug wires or COP ignition coils are sparking).
  • You know it's not a lack of fuel, because you've confirmed the fuel pump is OK (with a fuel pressure test).
• The engine oil is thick and tan to off-white color (mixed with coolant).

TEST 1: Engine Oil Mixed With Coolant

Pulling the dipstick out and checking if the engine oil sticking to it is a milky-white color is the very first test most auto repair techs/mechanics do to see if the engine has a blown head gasket.

If the engine oil on the dipstick is a milky-white color, then coolant has entered the crankcase and is mixing with the engine oil. With this result, we can conclude that we've got a blown head gasket.

These are the test steps:

1. 1

   Pop the hood open.

2. 2

   Pull out the engine's oil dipstick.

3. 3

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

4. 4

   You'll see one of two things:
   
   1.) The oil, sticking to the dipstick, is a creamy tan color (like coffee with too much cream) and is thick as syrup.
   
   2.) The oil is its normal color and viscosity.

Now, let's find out what each of the two results mean:

CASE 1: The engine oil, on the dipstick, is a light tan, like coffee with too much creamer. This is bad news and tells you that the head gasket or head gaskets are blown. The solution to this problem is replacing both head gaskets.

The biggest cause of coolant mixing with the engine oil is severe overheating. More specifically:

1.) When the engine overheated, the cylinder head or heads (which are made of aluminum) warped. This warping causes the head gasket (or gaskets) to burn.

2.) At this point, the head gasket or head gaskets can no longer keep coolant and engine oil separate.

3.) Once the head gasket looses it's sealing ability, coolant entering the engine oil pan. As both oil and coolant mix, the resulting combination gets thick and becomes an off-white color.

CASE 2: The color of the engine oil is normal. Although this is a good result, you're not out of the woods yet. I suggest doing the two other tests I'm presenting in this article. Go to: TEST 2: Compression Pressure And/Or Exhaust Gas Exiting The Radiator.

Here's why: Normally (about 90% of the time) when a head gasket gets blown on a 4.6L, 5.4L Ford van (or car, pick up, SUV), coolant will enter into the crankcase and mix with the engine oil. This isn't an absolute truth. Thankfully, there are several more tests that you can do to make sure that the head gasket is really blown or not. The next test is to see if the engine's compression/combustion gases are escaping thru' the radiator.

TEST 2: Compression Pressure And/Or Exhaust Gas Exiting The Radiator

The next test is as easy as the first one! In this test, we're gonna crank the engine with the coolant expansion tank cap off (see photo above).

If the coolant remains undisturbed (in the tank) while cranking the engine, then we can move on to the next test (since this is the expected test result).

If the coolant gets forcefully expelled while cranking the engine, it's a sign you've got a blown head gasket on your hands.

IMPORTANT: If the engine has been running for any length of time or it's hot, let it cool down for at least 1 hour. This is important, or you run the risk of getting scalded with hot coolant.

OK, here are the test steps:

1. 1

   Remove the cap from the coolant expansion tank.

2. 2

   Check the coolant level.
   
   If empty, add some water to bring the coolant level to full.

3. 3

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

4. 4

   You'll see one of two results:
   
   1.) The water or coolant inside the radiator will shoot up and out.
   
   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 coolant expansion tank.

Let's take a look at what your results mean:

CASE 1: The coolant shot out from the radiator (or expansion tank). This is bad news and this let's you know beyond a shadow of a doubt that the head gasket on your 4.6L, 5.4L Ford van (or car, pick up, SUV) is blown. No further testing is required.

CASE 2: The coolant DID NOT bubble out NOR shoot out from the radiator (or expansion tank). This is the correct and expected test result.

Now, if the engine starts and runs but has a misfire or rough idle and doesn't overheat, go to: TEST 3: Checking Cylinder Compression.

If the engine starts and runs fine but overheats within minutes of starting, go to: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).