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TEST 4: Using A Chemical Block Tester (Combustion Leak Tester)
In some cases the head gasket will fail but it will not cause the engine oil to mix with coolant and it won't cause the coolant to the to be shot out of the filler neck while cranking the engine. Also, the engine will crank, start, and run but it will overheat for no apparent reason.
In these cases the only way to confirm or exonerate the head gasket It Is by doing a simple block test.
You can buy a block tester in just about any auto parts store. 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 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? At your local auto parts store or here:
20%$10.40
If this info saved the day, buy me a beer!
