Leak Tests

Checking for Leaks




Attach the Rotunda Manifold Gauge Set 063-00010 or equivalent. Leave both manifold gauge valves at the maximum clockwise (closed) position. Both gauges should show approximately 413-551 kPa (60-80 psi) at 24°C (75°F) with engine not running. If very little or no pressure is indicated, leave the vacuum pump valve closed, open the R-12 tank valve, and set the low-pressure (suction) manifold gauge valve to the counterclockwise position. This opens the system to tank pressure.

Leak Detectors, Flame Type




The illustration shows a Rotunda Flame-Type Leak Detector, Model 023-00006. If a flame-type leak detector is to be used, the Rotunda device or its equivalent, is recommended.

CAUTION: Avoid inhaling fumes from the detector.

The smaller the flame the more sensitive it is to leaks. Therefore, to ensure accurate leak indication, keep the flame as small as possible. The copper element must be red hot. If it is burned away, replace the element. Hold the open end of the hose just below each suspected leak point for two or three seconds. The flame normally will be almost colorless. The slightest leak will be indicated by a bright green-blue colored flame. Check the manifold gauge set and hoses, as well as the rest of the system, for leaks.

NOTE: GOOD VENTILATION IS NECESSARY IN THE AREA WHERE A/C LEAK TESTING IS TO BE DONE. IF THE SURROUNDING AIR IS CONTAMINATED WITH REFRIGERANT GAS, THE LEAK DETECTOR WILL INDICATE THIS GAS ALL THE TIME. ODORS FROM OTHER CHEMICALS SUCH AS ANTIFREEZE, DIESEL FUEL, DISC BRAKE CLEANER OR OTHER CLEANING SOLVENTS CAN CAUSE THE SAME PROBLEM. A FAN, EVEN IN A WELL VENTILATED AREA, IS VERY HELPFUL IN REM0VING SMALL TRACES 0F AIR CONTAMINATION THAT MIGHT AFFECT THE LEAK DETECTOR.

Leak Detector, Electronic

Fig. 18 Leak Detector:

Use Rotunda Electronic Leak Detector 055-00014, 055-00015 or equivalent.

The electronic leak detector is operated by moving the control switch to the ON position. The detector automatically calibrates itself when it is turned on. Move the probe approximately 25mm (1 inch) per second in the suspected area. When escaping refrigerant gas is located, the ticking/beeping signal will increase in ticks/beeps per second. If the gas is relatively concentrated, the signal will be increasingly shrill. Follow the instructions included with the detector to improve handling and operating techniques.

Evaporator Core and Condenser On-Vehicle Leak Test
If an evaporator core or condenser is suspected of leaking, the leak must be verified prior to removing the component from the vehicle This leak test should be performed as outlined below. DO NOT rely solely on the results of an electronic leak detector as chemicals other than R-12 will activate the leak detector.
1. Discharge and evacuate the refrigerant from the system following the recommended service procedure. Refrigerant Recovery
2. Disconnect the inlet and outlet connections from the evaporator core or condenser and immediately install protective caps on the removed connections to prevent excess moisture from entering the system.




3. As shown in the illustration, install the mating adapters from the evaporator core/condenser Leak Test Adapter Kit, Tool D88P-19703-B or equivalent on both fittings of the component being tested.
4. Connect the two outside hoses of a manifold gauge set to the adapter fittings. Be sure the connections are tight.
5. Connect the center hose of the manifold gauge set to a vacuum pump. Start the vacuum pump and open the valves of the gauge set.
6. Operate the vacuum pump and watch the low pressure gauge. It should show almost 30 in-Hg within one or two minutes. Then, close the gauge set valves and stop the vacuum pump.
7. Observe the low pressure gauge for 15 minutes and watch for a drop in the gauge reading. If the gauge reading drops, the component is leaking and should be replaced. If a slow leak is suspected, leave the component connected to the gauge overnight. If the gauge reading does NOT drop, the component is not leaking. Look elsewhere for the source of the leak.
8. Disconnect the vacuum pump, manifold gauge set and the adapters from the component being tested.
9. Assemble the original component into the system if it was not leaking. Use new 0-rings lubricated with clean refrigerant oil
10. If the component was leaking, install a new part and a new suction accumulator. Use new 0-rings lubricated with clean refrigerant oil.
11. Leak test, evacuate and charge the system following the recommended service procedures. Refrigerant Recovery Evacuation and Charging