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Intake Manifold

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Gasoline-powered engines make use of an intake manifold to supply the engine cylinders with fuel-and-air mixture, which is necessary to kick off combustion. If there's leak in the manifold, air can get inside and affect the ratio of air and fuel, causing the engine to run lean. It can also cause coolant to leak out and result in engine failure.

Any leak in the manifold.whether air leak or coolant leak.should be dealt with immediately as it signifies irregularity in the system, which can hurt the performance of the engine. If you suspect intake manifold leak, here are the ways to detect them:

What you'll need:

  • Flashlight
  • UV leak detection light
  • Eye glasses with yellow lenses
  • Carburetor cleaner (with spray tube)
  • Leak test dye (for the cooling system)

Step 1: Look for signs of coolant leaks.

Check the area where the intake manifold tubes or runners connect to the engine. Turn the flashlight on and search for signs of coolant leaks. In minor cases, the signs will be stains or wet spots around the tubes while in severe cases, you'll notice puddles of coolant or some parts of the manifold will be wet with coolant. Depending on how severe the leak is, the coolant can also run down over the engine's front or rear.

If you still aren't sure that the leak is coming from the manifold, do some more checks.

Step 2: Use the coolant leak test dye.

Apply the coolant leak dye to the radiator fill cap and put the cap back in place. Start the engine and allow it to warm up. Once it has warmed up completely, turn the engine off. Allow it to cool down for several minutes, so you can work around it comfortably.

Wear the yellow glasses and aim the ultraviolet light around the spots where you suspect the intake manifold leak to originate. The dye in the coolant will look bright green in the leaking areas.

Step 3: Apply carburetor cleaner.

Get your can of carburetor cleaner and slide the spray tube into its nozzle. Start the engine, and while it is running, spray gentle and short burst of carburetor cleaner around the area where the manifold runners and the engine meet.

After spraying, listen to your running engine. If it seems like the engine speeds up or there's a change in the way it runs, you might have a leak in the intake manifold gasket.

If there's no change, spray again on the runners and listen if the engine speed will change. If it does, the cause of the problem may be a crack in the manifold. It's also wise to inspect the area between the manifold and the throttle body.

Warning: Make sure you're done with the test as soon as the engine heats up. It isn't advisable to use a carburetor cleaner on a hot engine because stray sparks can cause fire. It is wise to keep a carbon dioxide fire extinguisher handy when using this method of detecting leaks.

Intake Manifold Articles

  • DIY: Detecting Intake Manifold Leaks

    Gasoline-powered engines make use of an intake manifold to supply the engine cylinders with fuel-and-air mixture, which is necessary to kick off combustion. If there\'s leak in the manifold, air can get inside and affect the ratio of air and fuel, causing the engine to run lean. It can also cause coolant to leak out and result in engine failure.

    Any leak in the manifold-whether air leak or coolant leak-should be dealt with immediately as it signifies irregularity in the system, which can hurt the performance of the engine. If you suspect intake manifold leak, here are the ways to detect them:

    What you\'ll need:

    • Flashlight
    • UV leak detection light
    • Eye glasses with yellow lenses
    • Carburetor cleaner (with spray tube)
    • Leak test dye (for the cooling system)

    Step 1: Look for signs of coolant leaks.

    Check the area where the intake manifold tubes or runners connect to the engine. Turn the flashlight on and search for signs of coolant leaks. In minor cases, the signs will be stains or wet spots around the tubes while in severe cases, you\'ll notice puddles of coolant or some parts of the manifold will be wet with coolant. Depending on how severe the leak is, the coolant can also run down over the engine\'s front or rear.

    If you still aren\'t sure that the leak is coming from the manifold, do some more checks.

    Step 2: Use the coolant leak test dye.

    Apply the coolant leak dye to the radiator fill cap and put the cap back in place. Start the engine and allow it to warm up. Once it has warmed up completely, turn the engine off. Allow it to cool down for several minutes, so you can work around it comfortably.

    Wear the yellow glasses and aim the ultraviolet light around the spots where you suspect the intake manifold leak to originate. The dye in the coolant will look bright green in the leaking areas.

    Step 3: Apply carburetor cleaner.

    Get your can of carburetor cleaner and slide the spray tube into its nozzle. Start the engine, and while it is running, spray gentle and short burst of carburetor cleaner around the area where the manifold runners and the engine meet.

    After spraying, listen to your running engine. If it seems like the engine speeds up or there\'s a change in the way it runs, you might have a leak in the intake manifold gasket.

    If there\'s no change, spray again on the runners and listen if the engine speed will change. If it does, the cause of the problem may be a crack in the manifold. It\'s also wise to inspect the area between the manifold and the throttle body.

    Warning: Make sure you\'re done with the test as soon as the engine heats up. It isn\'t advisable to use a carburetor cleaner on a hot engine because stray sparks can cause fire. It is wise to keep a carbon dioxide fire extinguisher handy when using this method of detecting leaks.