Troubleshooting A Blown Head Gasket (Ford 4.6L, 5.4L)

Finding out if your Ford 4.6L or 5.4L car (pick up, SUV, or van) has a blown head gasket is not hard do to and in this article I'll show you four of the most effective tests that you can do to find out.

Two of these four tests, can be done in under 10 minutes. The third one involves doing a compression check and the last one involves using a combustion leak tester (commonly known as a block tester).

I'll guide you step by step thru' all four. More than likely, the first two test will confirm a blown head gasket (if indeed this is what has happened to your Ford vehicle).

You can find this tutorial in Spanish here: Cómo Verificar un Empaque de Cabeza Quemado (4.6L, 5.4L Ford) (at: autotecnico-online.com).

Importantips And Suggestions

TIP 1: You should never open a radiator with a hot engine. The coolant will be under pressure and opening the radiator cap can cause hot coolant to scald you as it coming spraying out.

Be careful, take all necessary safety precautions and use common sense. Your safety is your responsibility.

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 because: 1) Fan clutch is not working, 2) All of the coolant leaked out of the engine and you kept driving it this way. 3) Thermostat went bad and is stuck closed and the coolant could not circulate. The most common symptoms a blown head gasket are:

1. Your Ford 4.6L, 5.4L van (or car, pick up, SUV) is overheating. You know it's not the fan (or fan clutch) or thermostat.
2. White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
3. Your Ford 4.6L, 5.4L van (or car, pick up, SUV) won't start.
   • You have already verified it's not an ignition system problem because you have spark coming out at all of the spark plug wires.
   • You know it's not a lack of fuel, because you have verified that the fuel pump is delivering fuel to the fuel injectors.
4. The engine oil is thick and tan to off-white color (mixed with coolant).

TEST 1: Engine Oil Mixed With Coolant

One of the most common end results of a blown head gasket is coolant entering the crank case and mixing with the engine oil. So, our first test is to see if the engine oil is mixed with coolant.

This is what you need to do:

1. 1

   Pop the hood on your Ford 4.6L, 5.4L van (or car, pick up, SUV).

2. 2

   Pull out the engine's oil dipstick.

3. 3

   Check what the color of the oil is and how thick it is. What you're doing is confirming 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 is not 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.