TEST 2: Coolant Shooting Out Of Radiator
If you're coming to this test from TEST 1, then you have verified that the engine oil is OK and not a milky white color.
Just to make sure the head gasket is OK, on your 2.3L Ford Ranger or 2.3L Ford Mustang, the next step is to see if coolant will violently shoot out of the radiator (with the radiator cap removed) while the engine is cranking.
Now, if coolant shoots out of the open radiator while you're cranking the engine, then this will confirm, beyond a shadow of a doubt, that your 2.3L Ford Ranger or 2.3L Ford Mustang overheated to the point of blowing the head gasket and/or warping or cracking the cylinder head.
IMPORTANT: Don't perform this test on a hot engine! The coolant could be under a lot of pressure and could cause severe burns! Perform this test with a cold engine!
This is what you need to do:
- Remove the radiator cap from the radiator.
- NOTE: The engine should be completely cold before you open the radiator cap.
- Check the coolant level and if low, top it off before going on to the next step.
- Place yourself at a safe distance (from the engine) but within eye-view of the radiator.
- When ready, have your helper crank the engine.
- You'll see one of two results:
- The coolant shoots out violently when the engine was cranked.
- The coolant was not disturbed at all.
Let's examine your test result:
CASE 1: The coolant shot out of the radiator. Sorry to inform you that this test result tells you, beyond a shadow of a doubt, that you do have a blown head gasket and/or a warped or craked cylinder head on your 2.3L Ford Ranger or 2.3L Ford Mustang.
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.
But if you still think that you do have a blown head gasket on your 2.3L Ford Mustang or Ranger, read the next test. Go to TEST 3: Engine Compression Test.
TEST 3: Engine Compression Test
There have been several times, over the years, that the vehicle I was diagnosing for a blown head gasket didn't have coolant mixing with the oil and were not shooting the coolant out of the radiator when the engine was cranked.
Yet a blown head gasket they did have and the most important factor that all of these vehicles shared was that they had severely overheated and after the fact, they had a misfire/ rough idle condition.
After doing all of the basic tests, mentioned in TEST 1 and 2 and checking the basics like spark and fuel injector operation (on the misfiring cylinders),, the test that nailed the problem was a compression test.
The compression test confirmed that the cylinder head gasket had burned between to cylinders that were side-by-side and from the same bank of cylinders. The end result of this was (and is) 0 PSI compression on those two cylinders.
How does this happen? This happens because the head gasket burns between two cylinders and thus the compression from one cylinder escapes into the other and vice versa.
OK, to get this show on the road, this is what you'll need to do:
- Disable the fuel system and the ignition system.
- Remove the fuel pump relay to disable the fuel system.
- Disconnect both coil packs from their connectors to disable the ignition system.
- Remove the exhaust manifold side spark plugs only.
- The intake manifold side spark plugs must remain in place on the engine.
- Install the compression tester (hand tight only) on the first cylinder you're gonna' test.
- Have a helper crank the engine while you observe the compression tester.
- Write down the compression readings.
- Repeat steps 1 through 5 on the next cylinder.
Let's now take a look at your test result:
CASE 1: You got 2 side by side (adjacent) cylinders with 0 PSI. This confirms beyond a shadow of a doubt that you do have a blown head gasket on your hands.
To be a bit more specific: Adjacent cylinders would be: #1 and #2 OR #2 and #3 OR #3 and #4 only.
CASE 2: All cylinders had sufficient compression. After having done 3 tests, you have confirmed that you do not have a blown head gasket on your 2.3L Ford Ranger or 2.3L Ford Mustang. But, and there's always one isn't there, if your 2.3L Ford is still overheating and you still suspect a blown head head gasket, go to: TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).