TEST 2: Coolant Shooting Out From Opened Radiator
For our second head gasket test, we're gonna' crank the engine with the cap removed from the radiator to see if the coolant will be shot out from it.
The correct and expected test result is for the coolant to remain undisturbed (in the radiator) as the engine is cranked.
If the coolant is shot out while cranking the engine, then you can conclude that the head gasket is blown on your 2.2L Isuzu Amigo or Rodeo.
IMPORTANT: Never open or remove the 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. You can also cool down the engine in a matter of 15-20 minutes by placing a running box fan on top of it.
These are the test steps:
- 1
Remove the cap from the radiator.
If the radiator is empty, add some water or coolant to it. - 2
Have your helper crank the engine while you stand at a safe distance from the open radiator.
- 3
You'll see one of two results:
1.) The water or coolant inside the open radiator 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 open radiator.
Let's examine your test results:
CASE 1: Coolant shot out of the open radiator as you cranked the engine. This test result confirms that you have a blown head gasket on your 3.9L V6 Chevy Malibu engine.
The normal test result is for the coolant to not be disturbed as you crank the engine.
CASE 2: The coolant WAS NOT disturbed as you cranked the engine. This is the correct and expected test result.
If the engine does not start, then your next step is: TEST 3: Engine Compression Test.
If the engine starts and runs but overheats 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
In some cases, when the engine overheats, the head gasket gets burned right between two side by side cylinders.
The end result of this type of head gasket failure is an engine that won't start.
We can find out if this has happened by doing a engine compression test.
These are the test steps:
- 1
Disable the ignition system by disconnecting the ignition coil pack from its engine wiring harness connector.
- 2
Remove all four spark plugs.
- 3
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. - 4
Have a helper crank the engine. The compression gauge's needle should climb as the engine cranks.
- 5
Once the gauge's needle stops climbing, have your helper stop cranking the engine.
- 6
On a piece of paper, write down the compression reading and what cylinder it belongs to (you can use the illustration above to help you identify the cylinder). Repeat the above steps in the remaining cylinders.
Let's examine your test results:
CASE 1: Two side by side cylinders have 0 PSI compression. This test result confirms that the head gasket is blown only if the 'engine no-start' problem was preceded by a severe overheating problem.
CASE 2: The compression values of all 4 cylinders were similar. This is the correct and expected test result.
If your 2.2L Isuzu Amigo or Rodeo doesn't start, then you can conclude that the problem is not caused by a blown head gasket.
