HVAC System - General Servicing Procedures: Other Dodge Cab & Chassis R2500

HANDLING/SAFETY PRECAUTIONS

1. Always work in a well-ventilated, clean area. Refrigerant is colorless and invisible as a gas. Refrigerant is heavier than oxygen and will displace oxygen in a confined area. Avoid breathing refrigerant vapors. Exposure may irritate eyes, nose and throat.
2. Always wear eye protection when working around A/C system and refrigerant. The system's high pressure can cause severe injury to eyes and skin if a hose were to burst. If necessary, wear rubber gloves or other protective clothing.
3. Refrigerant evaporates quickly when exposed to atmosphere, freezing anything it contacts. If liquid refrigerant contacts eyes or skin (frostbite), DO NOT rub eyes or skin. Immediately flush affected area with cool water for 15 minutes and consult a doctor or hospital.
4. Never use R-134a in combination with compressed air for leak testing. Pressurized R-134a in the presence of oxygen (air concentrations greater than 60 percent by volume) may form a combustible mixture. DO NOT introduce compressed air into R-134a containers (full or empty), A/C system components, or service equipment.
5. DO NOT expose A/C system components to high temperatures (steam cleaning for example), as excessive heat will cause refrigerant system pressure to increase. Never expose refrigerant directly to open flame. If refrigerant needs to be warmed, place bottom of refrigerant tank in warm water. Water temperature must not exceed 125°F (52°C). CAUTION: When R-134a is exposed to an open flame, drawn into engine, or detected with a Halide (propane) leak tester, a poisonous gas is formed. Keep work areas well ventilated.
6. Use care when handling refrigerant containers. DO NOT drop, strike, puncture, or incinerate containers. Use DOT 4BW or DOT 4BA approved refrigerant containers.
7. Never overfill refrigerant containers. The safe filling level of a refrigerant container MUST NOT exceed 60 percent of the container's gross weight rating. Store refrigerant containers at temperatures less than 125°F (52°C).
8. R-134a refrigerant is sold and stored in 30- or 50-pound Light Blue containers, while Freon (R-12) is stored in White colored containers.
9. Refrigerant R-12 and R-134a must never be mixed, as they and their desiccants and lubricants are not compatible. If the refrigerants are mixed, system cross-contamination or A/C system component failure may occur. Always use separate servicing and refrigerant recovery/recycling equipment.
10. Read and follow equipment manufacturer's instructions for all service equipment to be used. The Material Safety Data Sheet (MSDS), provided by refrigerant manufacturer/supplier, contains valuable information regarding the safe handling of refrigerants.

IDENTIFYING R-134a SYSTEMS & COMPONENTS

To prevent refrigerant cross-contamination, use following methods to identify R-134a based systems and components.

Fittings & "O" Rings

All R-134a based A/C systems use 1/2" - 16 ACME threaded fittings (identifiable by square threads) and quick-connect service ports. (Scheme 16)

Scheme 16

REFRIGERANT OILS

Refrigerant R-12 based systems use mineral oil, while R-134a systems use synthetic Polyalkylene Glycol (PAG) oils. Using a mineral oil based lubricant with R-134a will result in A/C compressor failure due to lack of proper lubrication.

Following are the most common R-134a refrigerant oils used by most domestic vehicles

DaimlerChrysler Corp. & Jeep

Use ND-8 PAG oil, SUN PAG 56 oil, SP-10 PAG Oil, SP-15 PAG Oil, or SP-20 PAG oil.

Ford Motor Co.

Use YN-12B or YN-12C PAG Refrigerant Oil (specification WSH-M1C231-B) or SP-20 PAG Oil (specification WST-M1C231-B2).

General Motors

On all models except Saturn, use PAG Refrigerant Oil (Part No. 12345923). On Saturn, use Saturn PAG refrigerant oil.

Note. PAG oil absorbs moisture very rapidly, 2.3-5.6 percent by weight as compared to a mineral oil absorption rate of 0.005 percent by weight.

Note. Use ONLY the specified oil for the appropriate system or A/C compressor. Always check the underhood A/C specification label or A/C compressor label before adding refrigerant oil to A/C system.

SCHRADER-TYPE VALVES

Note. Although similar in construction and operation to a tire valve, NEVER replace a Schrader-type valve with a tire valve.

Schrader valve is similar in construction and operation to a tire valve. (Scheme 17) When a test gauge hose is attached (hose has built-in valve core depressor), Schrader stem is pushed inward to the open position and allows system pressure to reach the gauge.

If test hose being used does not have a built-in core depressor, an adapter must be used. Never attach hoses or adapters to a Schrader valve unless it is first connected to manifold gauge set.

Schrader Service Valve (Compressor Location Shown). Scheme 17

SPECIAL VALVE CONNECTORS

On some General Motors models, thread size on high-side service valve (3/8" - 24 threads) is different from thread size on low-side service valve (7/16" - 20 threads). Special adapters are required to make this connection. (Scheme 18) These adapters are available in 45-degree and 90-degree angles in addition to straight-fixed and flexible adapters.

Flexible High Side Adapter. Scheme 18

R-134a SERVICE VALVES/PORTS

All vehicles with R-134a refrigerant use quick-disconnect service valves/ports. All R-134a systems use quick-disconnect fittings with sealing caps that thread into inside of service port instead of onto outside of service port.

The high side uses a large service port, and the low side uses a small service port. (Scheme 16) The R-134a service ports have internal metric threads to help prevent the accidental connection of R-12 servicing equipment.

There are 2 types of quick-disconnect service couplings which can be used on R-134a systems. One type of service coupling depresses service port valve when connection is made. The other type connects onto service port but will not depress service port valve until a knob is rotated. (Scheme 19)

Scheme 19

SERVICE EQUIPMENT

Because R-134a is not interchangeable with R-12, separate sets of hoses, gauges, and recovery/recycling equipment are required to service vehicles. This is necessary to avoid cross-contamination and damaging system.

All equipment used to service systems using R-134a must meet SAE standard J2210. The service hoses on the manifold gauge set must have manual (turn wheel) or automatic back-flow valves at the service port connector ends. This will prevent refrigerant from being released into the atmosphere.

For identification purposes, R-134a service hoses must have a Black stripe along their length and be clearly labeled SAE J2196/134a. The low pressure test hose is Blue, with a Black stripe. The high-side test hose is Red, with a Black stripe. The center test hose is Yellow, or White, with a Black stripe.

Note. Refrigerant R-12 service hoses will only be labeled SAE J2196.

All R-134a manifold gauge sets can be identified by one or all of the following

1. Labeled FOR USE WITH R-134a on set.
2. Labeled HFC-134 or R-134a on gauge face.
3. Light Blue color on gauge face. In addition, pressure/temperature scales on R-134a gauge sets are different from R-12 manifold gauge sets.

MANIFOLD GAUGE SET

A manifold gauge set is used to determine the system's high-side and low-side pressures, correct refrigerant charge, and operating efficiency. High (discharge) and low (suction) pressures must be compared to determine system operation. Manifold gauge sets for the 2 refrigerant types are basically the same except for fittings at ends of hoses. Fittings are different to ensure connection only to appropriate refrigerant system.

Service hoses on gauge set should have a manual turn wheel or automatic back-flow valves at service port connector ends. This will prevent refrigerant from being released into the atmosphere.

1. Low-Side Gauge & Hose Low-side gauge, which may have a Blue identifying feature, is used to measure low-side (suction) pressure. Low-side gauge is also called a compound gauge because it can measure pressure and vacuum. Pressure scale ranges from 0 to 150 psi; vacuum scale ranges from 0 to 30 in. Hg. Low-side hose is Blue, with a Black stripe.
2. High-Side Gauge & Hose High-side gauge, which may have a Red identifying feature, is used to measure high-side (discharge) pressure. Gauge scale ranges from 0 to 500 psi. High-side hose is Red, with a Black stripe.
3. Center Manifold Hose Center manifold hose is either Yellow or White with a Black stripe. Center hose is used to recover, evacuate and charge refrigerant system. When low-side or high-side pressure valves are opened, refrigerant will escape through the charge hose.

CONNECTING GAUGE SET

Note. R-134a quick disconnect service couplings are connected in the same sequence as Schrader-type service valves.

1. Put on safety goggles, and cover vehicle's fender. Slowly remove protective caps from Schrader valves to check for leaky valves. CAUTION: Ensure hand valves on manifold gauge set and the hose-end shutoff valves are closed before attaching test hoses to Schrader valves.
2. Ensure service hoses are equipped with valve core depressor to match Schrader valve. If not, install special adapters for this purpose. If the high-side service hose connector will not fit on high-side Schrader valve, a special adapter must be used. See «SPECIAL VALVE CONNECTORS»(ref-91424-S26998438822001031400000) .
3. Ensure both manifold gauge set hand valves are closed. Connect low-side service hose to low-side (suction) service valve, and finger tighten connections. Connect high-side service hose to high-side (discharge) service valve, and finger-tighten connections.

Note. After test gauges are installed, test hoses must be purged of all air before proceeding with testing.

STABILIZING A/C SYSTEM

1. Once manifold gauge set is attached to system and test hoses have been purged, the system is ready for testing. Place all test hoses, gauge set and other equipment away from all moving parts of engine.
2. Start engine, and turn A/C controls to maximum cooling position (full cold or MAX A/C). Set blower on high speed. Open doors and/or windows. Operate system for 5-10 minutes. System should now be stabilized and ready for test readings.

PRESSURE-TEMPERATURE RELATIONSHIP

A refrigerant, when confined in an enclosed space, increases in pressure as the temperature increases. Conversely, if the temperature is lowered, the pressure also decreases.

Depending on temperature, a corresponding pressure will exist in such an enclosed space. For example, at 70°F (21.1°C) a gauge will indicate about 71.0 psi (5.0 kg/cm 2 ). The R-134a PRESSURE- TEMPERATURE RELATIONSHIP table shows this relationship.

R-134a PRESSURE-TEMPERATURE RELATIONSHIP

PRESSURE GAUGE READINGS

The pressure gauge readings shown represent an expansion valve type system using a Nippondenso 10-cylinder compressor. (Scheme 20)- (Scheme 28). Gauge indications will vary depending on system configuration and compressor application.

Temperature and humidity, as well as other factors, affect pressure gauge readings. Compared to R-12 systems, pressure readings on R-134a systems are generally lower for low-side pressure and higher for high-side pressure. Pressure gauge readings should be used only as a guide.

Note. For additional information, see the latest MITCHELL® AUTOMOTIVE AIR CONDITIONING BASIC SERVICE TRAINING MANUAL.

Normally Functioning R-134a A/C System. Scheme 20

Some Moisture In R-134a System. Scheme 21

Low R-134a Charge. Scheme 22

Poor R-134a Refrigerant Circulation. Scheme 23

No R-134a Refrigerant Circulation. Scheme 24

Insufficient Cooling Of Condenser Or R-134a Refrigerant Overcharge. Scheme 25

Air In R-134a System. Scheme 26

Expansion Valve Improperly Mounted Or Heat Sensing Tube Defective (Opening Too Wide). Scheme 27

Compressor Malfunction. Scheme 28

Note. Replace orifice tube whenever compressor is replaced. Fixed orifice tube is located in rear condenser-to-evaporator liquid line.

Note. DO NOT use pliers to remove fixed orifice tube or twist orifice tube in liquid line. Doing so will cause plastic orifice tube body to break inside condenser-to-evaporator liquid line.

Note. On Mustang, replacement of fixed orifice tube requires replacement of rear condenser-to-evaporator line and orifice tube assembly.

REFRIGERANT RECOVERY/RECYCLING

Refrigerant recovery/recycling equipment is used to remove refrigerant from vehicle's A/C system without polluting atmosphere. To remove and recycle refrigerant, always follow instructions provided with refrigerant recovery/recycling equipment being used.

Removed refrigerant is filtered, dried and stored in a tank within recovery/recycling equipment until it is ready to be pumped back into vehicle's A/C system.

Note. Separate sets of hoses, manifold gauge set and refrigerant recovery/recycling equipment must be used for R-12 and R-134a systems. DO NOT mix R-12 and R-134a refrigerants, as their refrigerant oils and desiccants are not compatible.

DAIMLERCHRYSLER CORP.

Manufacturer recommends using refrigerant recovery/recycling equipment which meets SAE standard J2210. Always follow instructions provided with the recovery/recycling equipment being used.

1. Connect hoses from Recovery/Recycling/Charging Center (023-00150) to high-side and low-side service valves. See «SERVICE VALVE LOCATIONS»(ref-91424-S38160178922001031400000) under SYSTEM SERVICE VALVES.
2. Turn equipment on and recover refrigerant according to equipment manufacturer's operating instructions. Allow equipment to operate until refrigerant is recovered. Close inlet valve (if equipped) on refrigerant recovery/recycling/charging center and turn equipment off. NOTE: On some applications, refrigerant recovery/recycling/charging center will automatically shut off through use of a low pressure switch. On other applications, refrigerant recovery/recycling/charging center must be manually shut off.
3. Allow A/C system to remain closed for about 2 minutes while observing vacuum pressure readings. If vacuum pressure reading increases, repeat step 2 until vacuum pressure readings remain stable for 2 minutes. If vacuum pressure readings remain stable for 2 minutes, disconnect hoses from service ports and perform required A/C system repairs.

Manufacturer recommends using A/C Refrigerant Recovery, Recycling & Recharging (ACR4) System (J-39500). ACR4 system has one filtering cycle during recovery plus an automatic multiple-pass filtering during evacuation cycle. Follow manufacturer's instructions provided with ACR4 equipment being used.

JEEP

Manufacturer recommends using refrigerant recovery/recycling equipment which meets SAE standard J1991 or J2210. Always follow instructions provided with recovery/recycling equipment being used.

Information is not available from manufacturer.

Note. DO NOT flush accumulator/receiver-drier, muffler, hoses and thermal expansion valve/fixed orifice tube, as residual flushing agent cannot be completely removed from these components. These components are generally replaced after A/C system contamination. Hoses can be reused, unless they are clogged with debris. Only flush evaporator core and condenser core, and metal inlet and outlet lines. These components can be flushed while installed in vehicle.

A/C System Filtering

1. If an A/C system flusher is not available to clean A/C system, an in-line filter kit can be used. Filter kit is installed before replacement compressor, accumulator/receiver-drier, muffler, and thermal expansion valve/fixed orifice tube have been installed.
2. Filter kits are used with either a rubber lined suction hose or with a nylon lined suction hose located between compressor and evaporator. Rubber lined hose has a wall thickness of 1/4" and nylon lined hose has a wall thickness of 1/8". (Scheme 29)
3. Filter kit for either type hose has 2 filters. A temporary pancake filter and a permanent in-line suction filter. Pancake filter is temporarily installed between condenser and condenser-to-evaporator line. (Scheme 30) Permanent filter is installed in suction line between accumulator and compressor.
4. Install replacement components (compressor, accumulator and fixed orifice) with correct amount of refrigerant oil. See COMPRESSOR REFRIGERANT OIL CHECKING article.
5. Cut suction hose between compressor and accumulator (closer to compressor). Remove a length of suction hose to accommodate suction filter. Measure side wall of suction hose and install appropriate filter with "O" rings and filter clamps. If side wall is 1/4", use in-line filter labeled USE WITH RUBBER INNER LINED HOSE. If side wall is 1/8", use in-line filter labeled USE WITH NYLON INNER LINED HOSE. Ensure arrow on filter is pointing in direction of refrigerant flow. Tighten hose clamps to 54 INCH lbs. (6 N.m). (Scheme 29)
6. Install pancake filter in liquid line between condenser and condenser-to-evaporator line. Ensure filter inlet (label) is toward condenser. Evacuate, charge, and leak test A/C system. See «EVACUATING A/C SYSTEM»(ref-91424-S39838271842001031400000), «CHARGING A/C SYSTEM»(ref-91424-S13109100412001031400000) and «LEAK TESTING»(ref-91424-S25795230732001031400000). Check filters and hoses for clearance from other engine components. Use tie straps if necessary.
7. Place external cooling fan in front of radiator. Select MAX A/C operation and set blower motor speed to maximum. Start engine and allow to idle. Ensure A/C is operating properly. Slowly increase engine speed to 800 RPM, then 1000 RPM, and then to 1200 RPM. With engine speed set to 1200 RPM, operate engine for one hour with A/C system operating.
8. Stop engine. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Remove pancake filter, hoses and fittings. Discard pancake filter. Reconnect liquid line, evacuate, charge, and leak test A/C system. Ensure A/C system is operating properly.

Scheme 29

Scheme 30

Information is not available from manufacturer.

Information is not available from manufacturer.

EVACUATING A/C SYSTEM

Caravan, Neon, 2001 Sebring Sedan, 2001 Stratus Sedan, Sebring Convertible, Town & Country, & Voyager

1. Connect approved recovery/recycling equipment and manifold gauge set. Fully open manifold gauge set low-side and high-side valves, and start vacuum pump. Operate vacuum pump for 45 minutes after low-side vacuum reading is 26 in. Hg or more (28 in. Hg or more on Neon). Close all valves and turn vacuum pump off.
2. If A/C system fails to reach specified vacuum, or does not maintain specified vacuum for at least 30 minutes, check for a defective vacuum pump or leak in A/C system or gauge set. See «LEAK TESTING»(ref-91424-S25795230732001031400000) . Perform repairs as necessary.
3. If A/C system maintains specified vacuum for at least 30 minutes, restart vacuum pump, open low-side and high-side valves, and evacuate system for an additional 10 minutes. Close all valves. Turn vacuum pump off and disconnect pump.

Cherokee, Dakota, Durango, Grand Cherokee, Ram Pickup, Ram Van/Wagon & Wrangler

1. Connect approved recovery/recycling equipment and manifold gauge set. Fully open manifold gauge set low-side and high-side valves, and start vacuum pump. Operate vacuum pump until low-side vacuum reading of 26 in. Hg or more. Close all valves and turn vacuum pump off. Observe vacuum gauge and go to next step.
2. If A/C system maintains specified vacuum for 5 minutes, restart vacuum pump, open low-side and high-side valves, and evacuate system for an additional 10 minutes. Close all valves. Turn vacuum pump off and disconnect pump.
3. If A/C system cannot get to or maintain specified vacuum, check for a defective vacuum pump or a leak in A/C system or gauge set. See «LEAK TESTING»(ref-91424-S25795230732001031400000) . Repair or replace components as necessary.

All Other Models

Connect approved recovery/recycling equipment to vehicle. Evacuate A/C system using recovery/recycling equipment according to manufacturer's instructions.

1. If using approved Recovery/Recycling/Charging Center (023-00150) connect to high-side and low-side service valves. See «SERVICE VALVE LOCATIONS»(ref-91424-S38160178922001031400000) under SYSTEM SERVICE VALVES. Connect manifold gauge set center hose to vacuum pump.
2. Open both valves on manifold gauge set. Operate vacuum pump until low-side vacuum reading is at least 29.5 in. Hg (as close to 30 in. Hg as possible). Operate vacuum pump for at least 45 minutes.
3. Close both valves on manifold gauge set. Turn off vacuum pump. Observe low-side gauge. Any loss of vacuum within 5 minutes indicates a system leak. Perform leak testing procedure. See «LEAK TESTING»(ref-91424-S25795230732001031400000) . Repair system as necessary and repeat evacuation procedure.

Manufacturer recommends using A/C Refrigerant Recovery, Recycling & Recharging (ACR4) System (J-39500). The ACR4 system has one filtering cycle during recovery, plus an automatic multiple pass filtering during evacuation cycle. Follow manufacturer's instructions provided with ACR4 equipment being used.

1. Connect approved recovery/recycling equipment and manifold gauge set. Fully open manifold gauge set low-side and high-side valves, and start vacuum pump. Operate vacuum pump until low-side vacuum reading of 26 in. Hg or more. Close all valves and turn vacuum pump off. Observe vacuum gauge, go to next step.
2. If A/C system maintains specified vacuum for 5 minutes, open low-side and high-side valves, restart vacuum pump and operate for an additional 10 minutes. Close all valves. Turn vacuum pump off and disconnect pump.
3. If A/C system cannot get to or maintain specified vacuum, check for a defective vacuum pump or leak in A/C system or gauge set. See «LEAK TESTING»(ref-91424-S25795230732001031400000) . Repair or replace components as necessary.

CHARGING A/C SYSTEM

Breeze, Cirrus & Stratus (Manifold Gauge Set Method)

1. Attach clamp-on Thermocouple (80PK-1A) to liquid line, as close to condenser outlet as possible. Attach manifold gauge set to vehicle.
2. Set parking brake, and place transaxle in Park. Start engine and allow to idle. Set A/C controls to outside air, panel mode, full cool, and high blower speed. Turn A/C on, and open windows. Operate system for a few minutes to allow system to stabilize.
3. Place cardboard over front grille area, to block airflow through part of condenser, to set A/C pressure to 260 psi (18.3 kg/cm 2 ). This will stop cooling fans from alternating speeds, and maintain constant pressure.
4. Record temperature reading at liquid line and discharge pressure reading on gauges. Compare readings with values in «REFRIGERANT CHARGE LEVEL»(ref-91424-S18374075432001031400000) table.
5. Depending on system charge condition, corrections are made 2 ounces at a time. Each time a correction is made, recheck readings to ensure proper charge. For system refrigerant capacity, see REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article.

REFRIGERANT CHARGE LEVEL

Concord, Intrepid, LHS, PT Cruiser & 300M

Manufacturer recommends using refrigerant recovery/recycling equipment which meets SAE standard J1991 or J2210. Always follow instructions provided with recovery/recycling equipment being used.

Neon, Sebring Sedan, 2001 Stratus Sedan, & Sebring Convertible

1. Ensure A/C system has no leaks and has been evacuated. See «EVACUATING A/C SYSTEM»(ref-91424-S39838271842001031400000) and «LEAK TESTING»(ref-91424-S25795230732001031400000) . If using a separate vacuum pump, close all valves before disconnecting pump. Connect approved recovery/recycling equipment and manifold gauge set to A/C service ports.
2. Measure specified quantity of refrigerant and oil. See REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article. Refer to recovery/recycling equipment operating instructions. Ensure engine is off. Open suction and discharge valves. Open equipment charge valve to allow refrigerant to flow into A/C system. When refrigerant transfer has stopped, close valves.
3. If all of refrigerant did not transfer, set parking brake and transmission to Park (A/T) or Neutral (M/T). Start engine and allow to idle at approximately 700 RPM. Close all windows and turn A/C on. Set A/C controls to 100 percent outside air, panel mode, blower motor to high speed and temperature to maximum cold.
4. If compressor does not engage, check clutch operation and control circuit. Perform repairs as necessary. Open suction valve (low pressure) to allow remaining refrigerant to transfer to A/C system. DO NOT open discharge (high pressure) valve at this time.
5. When transfer is complete, close all valve and ensure A/C system is operating properly. Disconnect recovery/recycling equipment, manifold set and replace service port caps.

Ensure A/C system has been checked for leaks and evacuated. See EVACUATING A/C SYSTEM and LEAK TESTING . Charge A/C system to specifications. For system refrigerant capacity, see REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article.

1. If using approved Recovery/Recycling/Charging Center (023-00105 or 023-00150), connect to high-side and low-side service valves. See «SERVICE VALVE LOCATIONS»(ref-91424-S38160178922001031400000) under SYSTEM SERVICE VALVES. Operate charging center according to manufacturer's instructions. Charge system with specified amount of refrigerant and refrigerant oil. See REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article. Check amount of refrigerant oil in system before adding oil. See COMPRESSOR REFRIGERANT OIL CHECKING article.
2. If using manifold gauge set, connect to high-side and low-side service valves. See «SERVICE VALVE LOCATIONS»(ref-91424-S38160178922001031400000) under SYSTEM SERVICE VALVES. Connect 2 hoses with shutoff valves to manifold gauge set center port. Connect one hose to vacuum pump and other hose to refrigerant container. Weight of refrigerant container before and after charging can be used to determine amount of refrigerant drawn into system. Using vacuum pump, purge air from center hoses.
3. Fully open manifold gauge set low-side valve and refrigerant container valve to allow refrigerant to enter A/C system. When no more refrigerant is being drawn into A/C system, start engine and allow to idle. Select MAX A/C, set blower motor speed to maximum and allow remaining refrigerant to be drawn into A/C system. NOTE: When ambient air temperature is high, it may be necessary to use an external cooling fan to blow air through condenser and radiator.
4. When proper amount of refrigerant has been added, close refrigerant container valve. Allow any refrigerant remaining in hose to be drawn into A/C system. When low-side pressure decreases to about 30 psi (2.1 kg/cm 2 ), close center valve on manifold gauge set. Ensure A/C system is operating properly. Disconnect manifold gauge set. Install service port caps. Check system for leaks. See «LEAK TESTING»(ref-91424-S25795230732001031400000) .

Manufacturer recommends using A/C Refrigerant Recovery, Recycling & Recharging (ACR4) System (J-39500). The ACR4 system has one filtering cycle during recovery, plus an automatic multiple pass filtering during evacuation cycle. Follow manufacturer's instructions provided with ACR4 equipment being used.

Connect recovery/recycling equipment, meeting SAE standard J1991 or J2210, to vehicle. Charge A/C system to specifications using equipment manufacturer's instructions.

Bubble Solution Detector

This is a solution applied externally at suspected leak points. Leaking refrigerant will cause detector to form bubbles and foam. A soap and water solution also works well.

Dye Solution

This is a colored solution that may be introduced into A/C system. Dye will show up and color components at leak points. Some manufacturers offer refrigerant containing a Red dye. This dye-containing refrigerant is installed by normal charging procedures. Other dye solutions are visible with a Black light only.

Fluorescent Leak Detection

Note. All 2001 model year GM passenger vehicles have a fluorescent leak detection tracer dye added to the A/C system. An underhood A/C charge label (when available) will have CONTAINS REFRIGERANT DYE on the label. Not all vehicles with the dye will have the new A/C charge label.

Note. Ford Motor Co. vehicles with A/C system fluorescent leak detection tracer dye will have a Green "X" on the accumulator.

One of the most effective ways to detect a leak in an A/C system is with fluorescent leak detention tracer dye. If fluorescent dye has been added during vehicle production, additional refrigerant dye for leak detection is not required. Dye added to A/C system during production will remain unless removed during a flushing process. Dye mixes with refrigerant oil, not refrigerant. On Ford vehicles, dye is visible using a 120 watt UV spot light. On GM vehicles, dye is visible using Yellow glasses and a High Intensity Black Light (J28428-E).

Electronic Leak Detector

This instrument will draw in any leaking refrigerant through a test probe, and then sound an audible signal or create a flashing light if refrigerant is found. It is the most sensitive of the leak detectors used. Leak detectors are sensitive to windshield washing solutions, many solvents and cleaners, and some adhesives. Ensure surfaces near test areas are clean and dry to prevent false signal or detector damage. Liquids ingested into detector will damage detector. (Scheme 31)

Electronic Leak Detector. Scheme 31