TEST 4: Using A Chemical Block Tester (Combustion Leak Tester)
In some cases, the head gasket failure will not cause any of the specific symptoms the three previous tests look to confirm.
What usually happens is that the engine will start and run but will overheat within minutes. Also, the engine's overheating issue seems to be caused by no apparent reason.
In these tough to diagnose head gasket problems, you'll need to perform an engine block test with a combustion leak detector (also known as a block tester).
In a nutshell, this is how a block tester 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 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 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 a blown head gasket, a cracked block, or a cracked cylinder head issue.
Where can you get the chemical and block tester? At your local auto parts store or here:
20%More 4.0L Ford Ranger (Mazda B4000) Tutorials
You can find a complete list of 4.0L Ford Ranger (Mazda B4000) tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test The Fuel Pump (1991-2011 Ford 4.0L Ranger And Mazda B4000).
- Fuel Pressure Specifications (1991-2011 4.0L Ford Ranger And Mazda B4000).
- How To Test Engine Compression (1991-2011 4.0L Ford Ranger And Mazda B4000).
If this info saved the day, buy me a beer!
