How To Test For A Blown Head Gasket (2.4L Chrysler, Dodge, Plymouth)

TEST 2: Coolant Shooting Out From Opened Radiator

One of the other symptoms of a blown head gasket is combustion or compression pressures inside the cylinders escaping into the engine cooling system.

We can very easily check this by removing the cap from the coolant filler neck and see if the coolant gets shot out of it while cranking the engine.

If coolant is forcefully shot out of the coolant neck, while cranking the engine, then we can conclude that the head gasket is blown.

If the coolant does not get disturbed while cranking the engine then we can move on to the next test.

NOTE: Your 2.4L Chrysler (Dodge or Plymouth) vehicle may have the coolant filler neck on the radiator (mini-van) or on the engine (see photo above).

IMPORTANT: Never open or remove the cap from the radiator or coolant filler neck if the engine is hot. If the engine has been running for any length of time, let it cool down completely. You can also cool down the engine in a matter of 15-20 minutes by placing a running box fan on top of it.

Let's get started:

1. 1

   Remove the cap from the coolant filler neck (or radiator). Check to see if there is coolant in it and if it's empty, add some water or coolant.

2. 2

   Crank the engine with the help of helper, while you stand at a safe distance from the open coolant tank.

3. 3

   You'll see one of two results:
   
   1.) The water or coolant inside the opened coolant reservoir will shoot 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 resevoir.

Let's examine your test results:

CASE 1: Coolant shot out of the opened reservoir tank as you cranked the engine. This test result confirms that the head gasket is blown on your 2.4L equipped Chrysler (Dodge or Plymouth) vehicle.

CASE 2: The coolant in the reservoir WAS NOT disturbed as you cranked the engine. This is the correct and expected test result. It confirms that compression pressures are not leaking into your engine cooling system.

If the engine in your vehicle is not starting then your next step is to test engine compression. For this test go to: TEST 3: Engine Compression Test.

If the engine in your vehicle is starting (and is overheating) then your next step is to do a block test. For this test go to: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).

TEST 3: Engine Compression Test

NOTE: This test only applies if the engine in your Chrysler (Dodge or Plymouth) vehicle is not starting. If the engine starts and overheats, then go to: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).

What we're looking for when testing engine compression to verify a blown head gasket, is to see if there are two side-by-side cylinders that have 0 PSI compression.

Here's why: In some cases the head gasket gets burned right between two side-by-side cylinders. This causes the compression of one cylinder to escape into the other and vice versa as you're cranking the engine.

The end result of these two dead side-by-side cylinders is that the engine will crank but not start.

We can easily confirm this by doing a simple compression test on all four cylinders.

These are the test steps:

1. 1

   Remove all four spark plugs.

2. 2

   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.

3. 3

   Have a helper crank the engine.
   
   The needle on the tester will climb, as the engine cranks, till the cylinder reaches its maximum compression.
   
   Once it stops climbing, have your helper stop cranking the engine.

4. 4

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

5. 5

   Repeat the above steps in the remaining cylinders.

Let's examine your test results:

CASE 1: The compression values of all cylinders were similar. This is the correct and expected test result and lets you know that he had gasket is not burned between two side-by-side cylinders.

If the engine is cranking but not starting, this test result lets you know that the head gasket is not behind this problem.

CASE 2: Two side-by-side cylinders have 0 PSI compression. This test result confirms that the head gasket is blown since it has burned between two side-by-side cylinders.