How To Test For A Blown Head Gasket (1997-2001 2.0L Honda CR-V)

By: Abraham Torres-Arredondo
Created: 24 January 2017
Updated: 20 March 2024
Articl Id: 612

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TEST 4: Using A Chemical Block Tester (Combustion Leak Tester)

Block Tester To Check For A Blown Head Gasket

Using a block tester is the 'go to test' when trying to diagnose a hard to diagnose blown head gasket condition on your 2.0L Honda CR-V.

This test comes in handy in the cases where the engine overheats every time you crank it up and drive vehicle but the engine oil is not mixed with coolant and the coolant isn't being shot out of the radiator (with its cap removed).

This is the one test that the professional repair shop will always perform to confirm a blown head gasket and it's one that you can do yourself.

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: