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

Block Tester To Check For A Blown Head Gasket

There are times when the prior 3 tests don't confirm or disconfirm that the head gasket is blown on your Honda. In a situation like this (when your Honda is still overheating after all that's been replaced or checked) a block test is the only way to confirm (or disconfirm) the problem.

Why didn't I start of with this test? Because TEST 1, TEST 2, and TEST 3 usually pin-point a blown head gasket condition in about 95% of the cases (not to mention you don't have to spend any $$ to do them). It's the remaining hard to diagnose 5% percent where the effort of finding a block tester is worth it.

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 thus confirming a head gasket, a cracked blocked, or cracked cylinder head issue.
  5. If the blue chemical doesn't change color, then you can conclude that you don't a head gasket, a cracked blocked, or cracked cylinder head issue.

You can buy one here:

Related Test Articles

There are several more ‘how to’ tutorials that I've written that are 2.2L and 2.3L Honda specific, that may be of further help. You can find them here: Honda 2.2L, 2.3L Index Of Articles.

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

  1. How To Test The Radiator Fan Motor (Honda 2.2L, 2.3L).
  2. How To Test The Radiator Fan Relay (Honda 2.2L, 2.3L).
  3. How To Troubleshoot A No Start (Honda 2.2L, 2.3L).
  4. How To Test A Misfire Condition (Honda 2.2L, 2.3L).
  5. How To Find A Bad Fuel Injector (Case Study).
  6. How To Test The Igniter, Ignition Coil, Spark Plug Wires, Distributor Cap (at: easyautodiagnostics.com).
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Honda Vehicles:

  • Accord 2.2L, 2.3L
    • 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002
  • Odyssey (EX LX) 2.2L
    • 1995, 1996, 1997, 1998
  • Prelude 2.2L
    • 1992, 1993, 1994, 1995, 1996

Acura Vehicles:

  • CL 2.2L
    • 1997, 1998, 1999

Isuzu Vehicles:

  • Oasis 2.2L
    • 1996, 1997, 1998, 1999