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

Block Tester To Check For A Blown Head Gasket. How To Test A Blown Head Gasket (1995, 1996, 1997 2.7L V6 Honda Accord)

I've diagnosed some blown head gasket cases where the engine did not present any of the usual symptoms that the previous 3 tests check for.

To be a bit more specific, the engine oil was not mixed with coolant, the coolant was not getting shot out of the opened radiator, and compression was good across all of the cylinders.

And yet the vehicle had a head gasket failure that was causing the engine to overheat.

In these hard to diagnose cases, only a 'block' test will confirm that a blown head gasket is causing the problem.

In a nutshell, this is how a block tester works:

  1. A blue liquid chemical, which is blue in color, is placed in the tester (see photo above).
  2. 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).
  3. 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.
  4. 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.
  5. 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:

More 2.7L V6 Honda Accord Tutorials

You can find a complete list of 2.7L V6 Honda Accord tutorials in this index:

  1. Honda 2.7L Index of Articles.

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

  1. Ignition System Wiring Diagram (1995-1997 2.7L Honda Accord).
  2. How To Test Engine Compression (1995-1997 2.7L Honda Accord).
  3. P0420 -What Does It Mean? (1996-1997 2.7L Honda Accord).
  4. How To Test The Ignition System (1995-1997 2.7L Honda Accord).
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Honda Vehicles:

  • Accord 2.7L V6
    • 1995,
      1996,
      1997