Many 1994 Tempo/Topaz covered by this guide are equipped with the new refrigerant (R-134a) to which the automotive industry is slowly changing over to prevent R-12 ozone damage. This new refrigerant is not available to the public in most areas and it is usually illegal to service a vehicle with this refrigerant (or R-12) unless certified. If you have a 1994 Tempo/Topaz, it is important to determine which A/C system the vehicle utilizes, and if it has R-134a the vehicle should be taken to a qualified technician for all A/C system service.
IDENTIFYING TYPE OF AIR CONDITIONING SYSTEM
See Figures 1 and 2
Until model year 1994, all Tempo/Topaz vehicles used R-12 in their A/C systems. Starting in 1994, Ford began offering some vehicles with R-134a instead of R-12. Because in this year there are cars that use R-12 as well as R-134a, and because these two refrigerants and their respective components are not interchangeable, it is very important to identify which type of system is in your car.
There are several different ways to tell which type of A/C system is installed in your car. The fist way is to look for the stickers in the engine compartment. There is an A/C refrigerant charge tag in the front of the car, above the radiator. Also if the car uses R-134a, there will be gold stickers placed along the various A/C lines. Several will be around the compressor, there are some before the condenser, and there is one before the accumulator.
Due to environmental concerns, when the A/C system is drained, the refrigerant must be collected using a refrigerant recovery/recycling equipments satisfying SAE J1990 and J2210 specifications. R-12 and R-134a must never be removed without the appropriate equipment.
Although R-12 and R-134a systems may appear similar in appearance, there are differences in design and function which require the use of different tools.
Do not use R-12 tools on R-134a A/C systems.
See Figure 3
Generally it is possibly to detect air conditioning system failures by a careful visual inspection. This includes check for broken belts, broken lines or hoses, obstructed condenser air passage or even disconnected wires.Checking For Oil Leaks
Refrigerant leaks show up as oily areas on the various components because the compressor oil is transported around the entire system along with the refrigerant. Look for only spots on all the hoses and lines, and especially on the hose and tubing connections. If there are oily deposits, the system may have a leak, and you should have it checked by a qualified technician.
A small area of oil on the front of the compressor is normal and no cause for alarm.Keeping the Condenser Clear
Periodically inspect the front of the condenser for bent fins or foreign material (dirt, bugs, leaves, etc.). If any cooling fins are bent, straighten them carefully with needle nose pliers, or a condenser comb which is available at most auto parts stores. You can remove any debris with a stiff bristle brush or compressed air.Operate The Air Conditioning System Periodically
A lot of air conditioning problems can be avoided by simply running the air conditioner at least once a week, regardless of the season. Let the system run for at least 5 minutes, and you'll keep the internal parts lubricated as well as preventing the hoses from hardening.
REFRIGERANT LEVEL CHECKS
The only way to accurately check the refrigerant level is to measure the system evaporator pressures with a manifold gauge set, although rapid on/off cycling of the compressor clutch usually indicates that the air conditioning system is low on refrigerant. Have a qualified shop check the system pressures. The normal refrigerant capacity for 1984-87 is 40-42 oz., for 1988-93 models is 35-37 oz. and 1994 models the capacity is 31-33 oz.
In most engine compartments, there is a sticker which details the capacity of the A/C system. This sticker now also indicates whether the A/C system uses R-12 or R-134a type refrigerant.
See Figures 4 and 5
Do not use gauge sets as a means for discharging the A/C system
Most of the service work performed in air conditioning requires the use of a set of 2 gauges, one for the high (Head) pressure side of the system, the other for the low (Suction) side.
The low side gauge records both pressure and vacuum. Vacuum readings are calibrated from 0 to 30 in.Hg and the pressure graduations read from 0 to no less than 60 psi (413.7 kPa). The high side gauge measures pressure from 0 to at least 600 psi (413.7 kPa).
Both gauges are threaded into a manifold that contains two hand shut-off valves. Proper manipulation of these valves and the use of the attached test hoses allow the user to perform the following services:
- Test high and low side pressures.
- Remove air, moisture and contaminated refrigerant.
- Purge the system (of refrigerant).
- Charge the system.
The manifold valves are designed so that they have no direct effect on the gauge readings, but serve only to provide for, or cut off, flow of refrigerant through the manifold. During all testing and hook-up operations, the valves are kept in a close position to avoid disturbing the refrigerant system. The valves are opened only to purge the system of refrigerant or to change it.Connecting the Manifold Gauge Set
Many states require any type of A/C work be done only by certified technicians. Heavy penalties are attached to those who do not follow the law.
The following procedure is for the connection of a manifold gauge set to the service gauge port valves. If charge station type equipment is used, consult the equipment manufacturer's instructions.
The high and low service gauge ports for a 2.0L engine are located in the refrigerant lines near the compressor. An adaptor ( YT-354 or equivalent) is required on the high service gauge port. For the 2.3L and 3.0L engines, the low service port is located near the accumulator, the high service port is located close to the compressor. An adaptor (YT-354 or equivalent) is required on the high service port.
- Make sure both the valves on the gauge are turned to their closed position.
- Remove the valve caps( if present) from the high and low service ports. Install the adaptor on the high service port.
- If the manifold gauge hoses do not have valve pins, adaptors T71P-19703-S and R or equivalent must be installed on to the hoses.
- Connect the high and low pressure hose to their respective ports, making sure each is installed correctly, and seated secure.
- By turning the valve on each gauge, an associated high or low reading will be given.
- Before removing the gauges, make sure each valve is closed. Slowly unscrew the fitting, and replace the valve caps. If there are no valve caps, consider purchasing them at an automotive parts store.
DISCHARGING THE SYSTEM
An approved R-12 recovery/recycling machine that meets SAE standards should be employed when discharging the A/C system.
- Operate the A/C system for at least 10 minutes.
- Attach the charging hoses, checking for proper connections and sealing. Shut off the A/C system and engine.
- Connect the center hose of the gauge to the approved recovery/recycling machine.
- Open the low side valve slightly. Open the high side valve slightly.
Too rapid a purging process will be identified by the appearance of an oily foam. If this occurs, close both hand valves a small amount until the condition stops.
- Close both valves when the pressures read 0, and all the refrigerant has left the system.
The A/C system should always be discharged before removing any hoses or components of the A/C system.
The discharging of an R-134a A/C system is similar to an R-12 system, with the exception that the equipment required for the job must be designed exclusively for R-134a A/C systems. Many states prohibit the servicing of any A/C systems without proper certification.
R-12 and R-134a tools are not interchangeable.
EVACUATING THE SYSTEM
- Attach the charging hoses, checking for proper connections and sealing. Ensure that all refrigerant has been discharged from the system.
- When all the pressure has been released from the system, connect the center charging hose to a vacuum pump.
- Close both valves on the gauge, if already not done. Start the vacuum pump.
- With the vacuum pump running, open the low pressure valve until fully open.
- Continue to evacuate the system with the vacuum pump until the low pressure gauge reads between 29.4-30.0 in Hg (99.4-101.1 kPa). Continue to run vacuum pump for additionally 30 minutes after desired low pressure reading is reached.
- Turn manifold gauges fully off, then turn off vacuum pump off. observe low pressure gauge for five minutes to be sure there is no change in pressure level. If there is a change, perform a leak test. If there is no change, the A/C system can be charged.
R-12 and R-134a tools are not interchangeable.
The procedures for evacuating an R-134a type A/C system are similar to an R-12 system, except that the tools required to do the work must be designed for an R-134a A/C system. Many states prohibit the servicing of A/C systems without proper certification.
The refrigerant charge level of the air conditioning system is critical to optimum performance. An under-charged or over-charged system will adversely affect A/C performance. To determine the correct amount of refrigerant, consult the A/C refrigerant label in the engine compartment.
The following procedure for charging an A/C system uses an A/C recovery/recycling machine. Because many of these machines are different, consult the manufacturers literature for details.
In many states, only certified technicians can service or charge A/C systems.
- Determine the correct amount of refrigerant needed in your A/C system.
- Connect respective low and high pressure hoses from the station to the vehicle's A/C system. Depending on the station being used, an adaptor may be needed on the high pressure valve from the car. Check for correct hook-up and secure fit.
- Disconnect the wire harness from the clutch cycling pressure switch and install a jumper wire across the 2 terminals.
- Slowly at first, open the low side valve on the station to add refrigerant. Make sure there are no leaks.
- Watch the gauges on the station, until no more refrigerant is drawn into the A/C system. start the car, insert a temperature probe into one of the vents, and turn the A/C system ON. Position the blower on HIGH.
- Continue to add refrigerant until the desired vehicle refrigerant weight is reached. Close the valves at the station, and slowly remove. There may be a slight loose of refrigerant as the lines are removed. Reinstall protective caps on the high and low side valves. If originally missing, purchase some at an automotive parts store. Reconnect the wire harness to the clutch cycling pressure switch.
- Continue to operate the A/C system, checking the temperature probe to make sure that the interior is truly cooling down.
The procedure for charging an A/C system with R-134a is similar, with the exception that R-134a requires a different set of tools and equipment. Many states require proper certification when working with R-134a.
Because the introduction and use of R-134a has only appeared recently on the automotive market, the availability of consumer oriented tools designed for this system is extremely limited, and those that are available are expensive. Also because of the environmental concerns related to A/C systems, state and federal governments have impose strict legislation to control the servicing and sale of A/C parts and equipment. This legislation is directed at both R-12 and R-134a type systems. It is very unlikely that this trend will change in the future. Because many states do not sell R-12 or R-134a to uncertified individuals, and because the tools necessary to service many A/C systems are extremely expensive when available, it is recommended that any A/C system repair be performed by Certified technicians.
Any A/C system that has lost it's refrigerant charge should be leak tested to be assured of an accurate diagnosis and satisfactory repair. Most refrigerant leaks occur around fitting and connections. These sully can be diagnosed by visual inspection.
There are several methods of detecting leaks in an A/C system, in addition to visual inspection. For example , there is the Halide Leak Detection method, in which a Halide Leak Detector emits a flame which turns a yellow-green in the presence of low levels of R-12, and purple or violet in the presence of large amounts of R-12.
Another method available to both R-12 and R-134a A/C systems is the Electronic leak detection system. Although the procedures are the same, different leak detectors will be needed for each type refrigerant. Depending on the type of unit, an electronic leak detector will emit a sound or display when it senses the presence of a refrigerant. The detector contains an extended probe which is run along the hoses, and around the components which make up the A/C system. Although the tools are relatively expensive, they are simple and legal to use, and could save you money in A/C service charges.