TEST 4: Using A Chemical Block Tester (Combustion Leak Tester)
Every now and then a blown head gasket problem will not show any of the symptoms that the previous 3 tests look for.
However, your the engine keeps overheating. In these hard-to-diagnose cases, the only way to confirm (or deny) a blown head gasket is to perform a block test with a chemical block tester.
The combustion leak tester (or block tester) test is so effective that it is used by all major repair shops to confirm a blown head gasket problem.
In short, this is how the test works:
- A blue liquid chemical, which is blue in color, is placed in the tester (see photo above).
- The tester assembly is then placed on the open radiator neck (you may have to drain some of the coolant in the radiator since this tool needs to 'gulp' some of the air inside the radiator).
- The engine is started.
- The rubber bellow is then squeezed to suck in the air up through the two fluid-filled chambers. As the air bubbles up through the fluid, it will cause a chemical reaction.
- If the blue chemical turns yellow (for gasoline engines), then combustion gases are entering the radiator. This result confirms a blown head gasket, a cracked block, or a cracked cylinder head issue.
- If the blue chemical doesn't change color, then you can conclude that you don't have a blown head gasket, a cracked block, or a cracked cylinder head issue.
Where can you get the chemical and block tester? Here:
20%Frequently Asked Questions
1.) How can I tell if the cylinder head is cracked?
To find out if the cylinder head is cracked, it must be removed from the engine block and subjected to a visual and/or pressure test.
If the crack on the cylinder head is wide enough, you can easily see it without a machine shop checking it.
If no cracks are visible to the naked eye, you still need to have it checked by a machine shop to be sure.
2.) How can I find out if the cylinder head is warped?
To find out, the cylinder head must be removed from the engine.
After removal, the head gasket surface of the cylinder head must be perfectly clean. A precision straight-edge tool (along with feeler gauges) is then used to accurately measure the warpage.
If your vehicle is overheating and the head gasket has blown, you can bet the cylinder head is warped and needs to be resurfaced by a machine shop.
3.) Do I need to resurface the cylinder head?
The answer is YES! You should never reinstall the cylinder head without first having a machine shop pressure test and resurface the cylinder head (especially if the engine overheated).
More 2.3L Ford Ranger Tutorials
A full list of 2.3L Ford Ranger and Mazda B2300 tutorials can be found here:
Here's a sample of the tutorials you'll find:
- How To Test The Throttle Position Sensor (1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 2.3L Ford Ranger, Ford Mustang, Mazda B2300).
- How To Test The Ignition Module And Crank Sensor (1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 2.3L Ford Ranger, Ford Mustang, Mazda B2300).
- Testing The Blower Resistor (1995-1997 2.3L Ford Ranger).
- How To Test The Engine Compression (1989-1997 2.3L Ford Ranger) .
If this info saved the day, buy me a beer!
