How To Test For A Blown Head Gasket (1.6L Honda Civic)

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

Sometimes, a blown head gasket doesn't want to reveal itself. In other words, the previous 3 tests just don't confirm a blown head gasket.

In these cases, the only way to make sure the head gasket is blown (or not) is by doing a block test.

This is how a combustion leak detector test (usually simply referred to as a block 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 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), combustion gases are entering the radiator. This result confirms a head gasket failure, a cracked block, or a cracked cylinder head issue.
• If the blue chemical doesn't change color, you can conclude that you don't have a head gasket failure, a cracked block, or a cracked cylinder head issue.

You can shop for a block tester here:

More 1.6L Honda Civic Tutorials

There are several more ‘how to’ tutorials that I've written that are 1.6L Honda specific, that may be of further help. You can find the ones that are located here, at this site, by going to the Honda 1.6L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test Misfire Codes (Honda 1.6L).
• How To Test The Throttle Position Sensor (Honda 1.6L).
• How To Troubleshoot A No Start (Honda 1.6L).
• How To Test The Igniter, Ignition Coil (Accord, Civic, CRV, and Odyssey) (at: easyautodiagnostics.com).