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The heater attributes with the help of a healthy and balanced cooling system and also the heater controls within the passenger compartment. Depending upon the symptoms, there are various reasons your customer’s heater can not be working. First, inspect the engine’s coolant level. If the coolant level is low, this may indicate that air is trapped in the heater core. Smooth coolant flow through the heater core is crucial for warmth output. Also, check coolant concentration. The mixture should be 50/50. A greater percentage mixture (more than 50 percent) will decrease heater performance. Us all know that when the automobile is running, heat produced by the engine is absorbed by the engine coolant, which then flows through the heater core, i m sorry is choose a small radiator. Fans and also blowers relocate fresh or recirculated air across the evaporator fins and heater main point to provide heated air for the climate control system.

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“ also with the pan turned increase high, the does not seem to ever before blow cool air!”


If the A/C device is no cooling the car to manufacturing facility specifications: examine to watch if the A/C compressor clutch is engaged and also the A/C device is completely charged. Girlfriend will likewise want to inspect if the HVAC doors and also the HVAC controls are working correctly.

An operational check will aid you verify that all HVAC mechanism controls and modes are operating correctly.

Air air conditioning (A/C) push diagnosis deserve to also aid pinpoint the worry with a malfunctioning system. However, learning what the gauges say have the right to be troublesome for part technicians. So we will take a look at at press diagnosis, however we must start by reviewing refrigerant and also how to determine if it may be the reason of the concern.

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Review that Refrigerant

Refrigerants room the vital working fluids in refrigeration systems. They transfer warmth from one location to another. Warmth is absorbed into the refrigerant by evaporation and released through condensation. In this manner, refrigerants readjust states as compelled by the system.

Refrigerant Purity Test

A tool that have the right to identify the materials of an A/C device is important in part diagnostic situations. The tool may additionally be compelled for A/C service centers according to regulation in her area.

If the refrigerant in a system has excess air yet has no other problem, removing the waiting will settle a high push or loss of performance problem. In fact, SAE recommends the usable refrigerant must contain no an ext than 2 percent concentration by weight of non-condensable gas (air).

However, if the system consists of air and/or various other refrigerants (for example, blended refrigerants), then the contaminated refrigerant have to be removed with one-of-a-kind recovery equipment and sent off-site for processing or destruction. The tools must be committed for the restore of contaminated refrigerant only! Caution should be taken once flammable refrigerants have actually been detected, consisting of the usage of distinct air-powered restore equipment.

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Using a Go/No-Go refrigerant detector for both organization situations have the right to only determine system contamination. Without refrigerant identification equipment, the refrigerant containing just air would certainly not it is in saved because the actual problem can not be identified with Go/No-Go equipment.

Refrigerant analyzers are accessible that meet or exceed SAE J2912 and can recognize gas samples taken directly from the refrigerant system or storage containers. The analyzer (models vary) screens R-134a if the purity is much better than 98 percent by weight. The unit screens FAIL if R-134a gas has not been figured out or if the is no at the very least 98 percent pure. If the detect gas contains a hydrocarbon (flammable material), the unit sounds an alarm and also displays HC. After analysis is made and displayed, the analyzer purges the unit of the sampled refrigerant and also is prepared for the following sample. Part units likewise indicate waiting concentration in enhancement to purity levels. Store in mind the you can have 100 percent pure refrigerant that could still be considered unacceptable due to high levels of non-condensable gas. Functions are obtainable on details models that enable the unit come accurately purge air come an acceptable level. This may be completed with the vehicle service valve or a refrigerant container.

If R-134a has actually not been established as 98 percent pure, the vehicle’s A/C mechanism should no be serviced with committed equipment. Always refer to the manufacturer’s accuse for suitable use that the refrigerant analyzer.


NOTE: For an ext information regarding refrigerant pollution or handle locations, call the eco-friendly Protection agency (EPA) hotline in ~ 800-296-1996 or end the web at www.EPA.GOV/ozone.


Excess air in the Refrigerant

If the recovery/recycling tools is not used properly, waiting can get in the system and also contaminate the refrigerant. Tools with an automatic air purge usually keeps the air pollution level at much less than 2 percent through weight, i beg your pardon is taken into consideration acceptable. However, recycling devices with a manually operated purge can enable high level of air right into the device usually as result of technician error. Recovery/recycling devices that has a hand-operated air purge should be confirm every day before the recycle refrigerant is used. If the container press is not checked, air will certainly transfer right into the system.

Air can likewise be added during the refrigerant recovery procedure from system and service hose leaks. Recovery tools that has an automatically shutoff in ~ a predetermined vacuum level will certainly not reach that level if a leak exists. The restore unit will continue to operate, drawing in air from the leak source and adding it to the storage tank. If the recovery unit has actually a correctly operating automatically purge, typically it will vent the excess air. If the waiting is not removed from the system, the mechanism will have actually performance problems.

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To perform top-quality A/C work, girlfriend will need to recognize if a container of recycle refrigerant is tainted through air. One way is to compare the pressure of the recycle refrigerant container through the press of a pure refrigerant container at a well-known temperature. If both pressures space equal, the refrigerant is thought about acceptable.

Use of proper Lubricants

PAG Oils

Synthetic-based PAG oil are offered with R-134a systems. PAG oils have a high hygroscopicity, which method they easily absorb moisture and retain the much simpler than mineral oil. Always tightly lid all PAG oil containers after each use.

There are several PAG oils with special additive packages and also different viscosities, which are supplied in current Nissan and also Infiniti vehicles, depending on the kind of compressor used. The is important to usage the exactly oil for the form of compressor being serviced. Because that vehicle details information, describe the proper Service hands-on or the vehicle’s A/C decal.

It is really important to have actually the correct amount that oil in the A/C system. This not only permits the system to operate properly but likewise ensures proper lubrication the the compressor. Too little oil will damages the compressor. Too much oil will alleviate the cooling capacity of the system.

If there has actually been one oil loss for any kind of reason, repair the cause of oil loss and refill according to the Refrigerant Oil Capacities graph in the organization Manual because that the auto being serviced.

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NOTE: Refrigerant oil (PAG lubricants) are accessible through the NissanMaintenance benefit program. Walk to www.NNAnet.com and click ~ above the “Maintenance Advantage” link.


Diagnosis and Repair of Under Hood Components

Leak Test

A leaking A/C system suggests the mechanism refrigerant level is reduced than specification.

Any time an ext than 0.5 lb. (0.23 kg) of refrigerant is required to fee the system over a period of a year, a leak is present. Leakage deserve to usually be traced to loose fittings, deteriorated hoses or seals, or damaged steel lines. Many leaks room the an outcome of typical engine vibration, which loosen fittings and also may bring about metal fatigue and cracks on steel lines end a period of time. In any type of case, these contents must be repaired or replaced to prevent added refrigerant loss.

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Many refrigerant leaks can be found through a straightforward visual inspection. While little leaks that a couple of ounces the refrigerant per year are complicated to detect, bigger leaks of about a lb per year can easily be isolated. This is because these huge leaks may sometimes leave the system fully empty. If this is the case, an initial inspect the mechanism for damaged hoses or feather lock couplings before performing a leak test.

During the visual inspection, be sure to inspect the company fittings after removing the gauges. Oil, stains or dust are good indications the a leak. Check the bottom of the evaporator real estate for oil, since oil regularly accumulates there once the evaporator fails. Examine for water tap leaks and also porous or worn tubing.

If the intuitive inspection stops working to disclose the source of a refrigerant leak, check the system using one of two people an digital leak detector or a map dye.

You might be forced to include up to a pound of refrigerant in order to locate the leak. To find the resource of a large leak, listen for a hissing sound or spray some soapy water on components and look for bubbles.

To execute the leak test, the mechanism must it is in under pressure. If the suction heat is cold v the mechanism operating, there is usually enough refrigerant in the device to execute the leak test. If not, refrigerant pressure deserve to be supplied from a charging terminal although that is not important to completely charge a mechanism for leak testing.

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Electronic Leak Detection

Electronic leak detectors space an accurate means of locating also the many elusive refrigerant leaks. The electronic leak detector is a portable, digital gas detector.

Electronic leak detectors must fulfill or exceed SAE J1627 to run properly top top R-134a. Girlfriend should additionally be aware that there room different types of digital leak detectors.

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Some the the an ext common varieties available this day are figured out by the adhering to classifications:

boil anode Heated solid electrolyte Corona suppression

Each kind has advantages and disadvantages, which is why the is so vital to follow the manufacturer’s operation instructions. Nevertheless of which form you have, all of them call for some type of routine maintenance to perform accurately.

One of the services of using digital leak detection is gift able come detect leaks at the time of A/C service. This reduce both refrigerant loss and also time affiliated as in the case of trace dye.

As declared earlier, most refrigerant leaks will certainly be uncovered at fittings and connections. The leak detector may not operate successfully if any kind of refrigerant has actually been exit under the hood from gauge hook-up or charging. If this is a problem, use low-pressure compressed wait or a pan to blow any kind of released refrigerant indigenous the engine compartment before leak testing.

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To discover a leak v an digital leak detector:

1. Begin the engine and also turn ~ above the A/C system. Allow the mechanism operate for 5 minutes.

2. Turn off the A/C system and also the vehicle. Wait 2-7 minutes.

3. Turn on the leak detector. Most digital leak testers have actually a battery voltage indicator, generally an LED display, which will certainly illuminate. If that does not, change the batteries before proceeding.

4. Search for leaks by gradually moving the sensor tip over all device components, consisting of controls, seals and also fittings.

5. The tester will certainly emit a sound once the sensing pointer detects refrigerant gases. Most digital testers have a thumbwheel to adjust detection sensitivity.


NOTE: you may need to increase the detection sensitivity the the sensing pointer itself. See the tester documentation for this procedure.


Trace Dye Test

Trace dye comes in different forms because that a variety of fluids including: engine oil, infection oil and also engine coolant. Over there are likewise different species used in A/C service; therefore, the is an extremely important that you use the correct type. Map dye is combined with a small amount that refrigerant lubricant. Compressor manufacturers are an extremely concerned about the enhancement of lubricants other than those mentioned on the vehicle’s label. This also applies to map dye; therefore, only use map dye that meets or exceeds Nissan or Infiniti approval.


NOTE: every Nissan vehicles are originally built with refrigerant trace dye (usually a pellet placed in the Rec. Drier/liquid tank).


The J-43926 Air air conditioning Dye Kit provides you through a method for adding trace dye to the A/C system. However, adding much more than stated to the A/C mechanism will no make the leaks more obvious. In fact, adding too much may reason the A/C device lubricant additives and also viscosity to break down.

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As you walk over the system, utilizing the black color light to inspect for indications of trace dye, perform not forget to check the evaporator condensate drain. Any kind of trace dye coming the end of this ar is a sure sign of an evaporator leak. On part vehicles, girlfriend may be able to view the evaporator surface with the black light by removing the fin probe assembly. A possibility exists that a small leak may occur without any signs of trace dye. Remember that the lubricant transports map dye, and also if the lubricant never ever reaches a leak source, no visual indications will be present. This is another reason why friend still need to use an electronic leak detector.

Finally, always attach the map dye to know sticker in the engine compartment close to the A/C decal. This will notify other technicians that the mechanism is currently equipped through trace dye to prevent excessive quantities in the lubricant. Throughout the black color light inspection if signs of trace dye were evident and the leak resource was repaired, girlfriend would must clean the area using the proper trace dye cleaning solution. This will eliminate confusion about any leaks in the future.


NOTE: map dye is blended with the PAG lubrication oil. The dye must circulate with the entire system before it will reach the resource of the leak. Therefore, you must allow enough time because that dye to circulate.

NOTE: Too much dye can influence the viscosity the the refrigerant oil.

NOTE: always wear the security eyeglasses the come through your black color light equipment. This will boost the luminescence of the dye, which will make the smaller sized leaks an ext apparent. An ext importantly, the eyeglasses safeguard your eyes from damaging ultraviolet light.


Follow this guidelines when you use trace dye come detect leaks:

1. Include minimal quantities of map dye to the A/C device according to the dye manufacturer’s directions.

2. Run the A/C device for 5-10 minute to circulate the dye transparent the system.

3. Bright an ultraviolet lamp on the A/C system and look because that traces the dye, denote leaks.

4. Although big leaks will display up quickly, little leaks may take numerous days to show up using this method. For additional information ~ above this technique of leak detection, describe the instructions provided with the dye.

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Manifold Gauge reading Evaluation

Now the you are acquainted with part diagnostic trial and error methods, the is time to evaluate few of the much more common diagnostic scenarios you may encounter. Once it involves refrigerant mechanism problems, you will need to have the ability to make a diagnosis based on pressure gauge readings. Over there are additionally a few techniques that will assist confirm your suspicions about those pressure gauge readings.

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Before girlfriend make any kind of determination regarding the press gauge readings, you require to think about the company port locations. Remember, these are the locations on the device where your gauges actually monitor the pressure. Gauge readings might not constantly indicate the same pressure throughout the entire high next or short side the the system. You might have a low-pressure analysis on the high-side gauge and still have actually a limit on the high-pressure side of the system. If the restriction is located prior to the high-side organization port, your readings will certainly be reduced than normal.

For example, if the high-side company port is located on the liquid tank and the hose in between the condenser and also the liquid tank is restricted, her gauge readings will be reduced than you may expect.

By analysis the gauges alone, you might be misled right into making an inaccurate diagnosis. Take into consideration all the factors, consisting of ambient temperature, condenser airflow, engine rpm and also humidity, i beg your pardon all impact the manifold gauge readings. Once you doubt a problem, try using the hand-feel temperature test on the lines and hoses to discover restrictions in the refrigerant system. Be careful; high-pressure refrigerant lines may become very hot!

Place a temperature gauge in among the waiting outlets in the passenger compartment. Place a 2nd temperature gauge in ~ the condenser to measure up ambient (outside) air temperature. Both temperatures space usually required to analyze device performance.

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Read the press gauges and compare them to factory specifications. Note that press gauge readings vary through ambient waiting temperature, humidity and also system design.

With an approximately temperature of 70° F (21° C), an orifice tube mechanism with a to ride bicycle switch need to have around 150-250 psi (1034.2-1723.7 kPa) high-side pressure and 24-31 psi (165.5-213.7 kPa) low-side pressure.

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If your pressure gauge readings are not within factory specifications, there is a difficulty in the system. You have to use these readings, various other symptoms, the service Manual and also your expertise of system operation to find the trouble v the system.