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Uses for Mityvac® P/N 04050 Hand Held Pressure/Vacuum Pump
Pressure testing a radiator cap |
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Note: The contents of this article describe only basic functions and testing of general application pressure operated components used in the manufacture of automobiles. The purpose of this article is to provide basic guidelines associated with testing and understanding engine related pressure components. For specific component testing, refer to the manufacturer’s published data for your vehicle make and model. |
One of the most misunderstood and often neglected systems on an automobile is the cooling system. The first misconception is that the water pump pressurizes the system, which is not correct; the water pump only circulates the coolant. Pressure in the cooling system is created as a running engine heats up the coolant, which causes it to expand and then seek a way out. To prevent the overheating of coolant, cooling fans are used to remove the heat and a pressure cap is used to maintain the pressure. This careful balance must be maintained so the engine does not run too cool or too hot. The manufacturer establishes the right temperature during the initial design and testing process so it is important to maintain the integrity of the pressure cap to keep the system balanced.
To test a typical pressure cap you will need the following:
1. A Mityvac“ P/N 04050 Silverline Plus‘ Automotive Test Kit, which includes a hand-held vacuum/pressure pump.
2. A length of vacuum hose (also included) that can adapt the pump to the overflow hose fitting with a hose clamp.
3. Manufacturer’s specification data. (This information is usually printed on the pressure cap).
General test procedures:
Warning: Do not perform this test on a hot or overheated engine. Ensure the vehicle has cooled down to prevent steam or liquid burns.
1. Remove the pressure cap from the radiator or pressure tank and visually inspect the seals. If they are cracked or distorted, replace the pressure cap before testing.
2. If the pressure cap is in good condition or has been replaced, disconnect the overflow hose and connect the Mityvac® P/N 04050 using the length of hose and hose clamps. (If testing the pressure cap on a tank assembly this would be the smallest hose attached near the top.)
3. Once you are connected, ensure the Mityvac“ P/N 04050 is set to the "pressure" position and begin pumping until you reach the pressure that the cap has printed on it.
4. As you reach this pressure you should hear an audible release of air from the pressure cap; this will indicate that the cap is working properly. If the pressure releases too quickly it will indicate that the cap is not functioning correctly (new caps do fail this test).
5. While performing this pressure test, you can also visually check the entire system for leaks.
Pressure testing an evap system
Note: The contents of this article describe only basic functions and testing of general application pressure operated components used in the manufacture of automobiles. The purpose of this article is to provide basic guidelines associated with testing and understanding engine related pressure components. For specific component testing, refer to the manufacturer’s published data for your vehicle make and model.
Since the introduction of the Mityvac® P/N 04050 Silverline Plus‘ Automotive Test Kit, the automotive industry has increased the requirements for emission testing throughout the world. This has presented the modern technician with a new method of testing that requires the use of a hand-held pressure pump kit. The type of pressure used in modern vehicle systems is generally a low pressure (below 25 psi) and is found in very sensitive devices that convert pressure to an electrical signal for the vehicle’s computer system. The computer processes this electrical signal and uses it to make any necessary adjustments, keeping the engine running at its optimal performance. One of the most common of these devices is known as an Evaporative Emission Sensor. This sensor actually measures the amount of fuel vapor pressure that is in the fuel tank of the vehicle. By testing the sensor one can eliminate the possibility of the Evaporative Emission Sensor being defective, detect a broken fuel
vapor hose or the fact that the fuel cap is loose or missing.
To test the sensor you will need the following:
1. Manufacturer guidelines or published data for the evaporative emission system.
2. The necessary tools to access the sensor
3. A DVOM (digital volt ohm meter)
4. A hand held pressure/vacuum pump like the Mityvac“ P/N 04050
5. Appropriate computer code reader that will access the trouble codes.
General test procedures:
1. Perform a visual inspection to ensure that everything is connected, not damaged and in place as it should be.
2. Verify that the computer system has set an evaporative emission system code.
3. Check to ensure that the fuel cap is tight and not damaged in any way.
4. Inspect the evaporative emission sensor connection and wiring for frayed wires or damage to the connectors.
5. Referring to the manufacturer’s data, test the sensor using the DVOM and the Mityvac“ Pressure Pump. This is usually performed with the key in the on position to provide power to the sensor; then use the vacuum/pressure pump to apply pressure to the "tank" side of the sensor while attaching the DVOM.
6. Compare the reading using the manufacturer’s data.
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