The heater features with the assist of a healthy and balanced cooling system and also the heater controls inside the passenger compartment. Relying on the symptoms, there are assorted reasons your customer’s heater could not it is in working. First, examine the engine coolant level. If the coolant level is low, this may suggest that wait is trapped in the heater core. Smooth coolant circulation through the heater core is critical for warm output. Also, inspect coolant concentration. The mixture should be 50/50. A higher percentage mixture (more than 50 percent) will decrease heater performance. We all recognize that while the auto is running, heat developed by the engine is absorbed by the engine’s coolant, which climate flows v the heater core, which is favor a little radiator. Fans and also blowers relocate fresh or recirculated air throughout the evaporator fins and heater main point to provide heated air because that the climate regulate system.

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“ also with the fan turned up high, that does no seem to ever blow cool air!”

If the A/C device is no cooling the automobile to factory specifications: examine to see if the A/C compressor clutch is engaged and also the A/C mechanism is fully charged. Friend will also want to check if the HVAC doors and the HVAC controls space working correctly.

An operational check will help you verify the all HVAC system controls and also modes room operating correctly.

Air air conditioning (A/C) push diagnosis have the right to also help pinpoint the worry with a malfunctioning system. However, understanding what the gauges say deserve to be troublesome for some technicians. So we will certainly take a watch at press diagnosis, but we have to start by reviewing refrigerant and also how to identify if it might be the reason of the concern.


Review of Refrigerant

Refrigerants room the crucial working fluids in refrigeration systems. They transfer heat from one location to another. Warmth is took in into the refrigerant by evaporation and released v condensation. In this manner, refrigerants change states as forced by the system.

Refrigerant Purity Test

A device that have the right to identify the components of an A/C mechanism is necessary in part diagnostic situations. The tool may likewise be required for A/C company centers follow to regulation in your area.

If the refrigerant in a system consists of excess air yet has no various other problem, remove the air will settle a high push or ns of performance problem. In fact, SAE recommends that usable refrigerant have to contain no more than 2 percent concentration by load of non-condensable gas (air).

However, if the system has air and/or other refrigerants (for example, combined refrigerants), climate the contaminated refrigerant should be eliminated with one-of-a-kind recovery equipment and also sent off-site for processing or destruction. The devices must be dedicated for the recovery of contaminated refrigerant only! Caution have to be taken as soon as flammable refrigerants have actually been detected, consisting of the usage of unique air-powered restore equipment.


Using a Go/No-Go refrigerant detector for both organization situations can only identify system contamination. Without refrigerant identification equipment, the refrigerant containing only air would not it is in saved since the actual problem could not be established with Go/No-Go equipment.

Refrigerant analyzers are available that accomplish or exceed SAE J2912 and also can identify gas samples taken straight from the refrigerant system or storage containers. The analyzer (models vary) display screens R-134a if the purity is far better than 98 percent through weight. The unit display screens FAIL if R-134a gas has actually not been established or if the is not at the very least 98 percent pure. If the recognize gas consists of a hydrocarbon (flammable material), the unit sounds an alarm and displays HC. After evaluation is made and also displayed, the analyzer purges the unit of the sampled refrigerant and also is ready for the next sample. Part units additionally indicate wait concentration in addition to purity levels. Save in mind the you might have 100 percent pure refrigerant that could still be taken into consideration unacceptable due to high level of non-condensable gas. Features are accessible on particular models that allow the unit to accurately purge air to an acceptable level. This may be completed with the automobile service valve or a refrigerant container.

If R-134a has actually not been determined as 98 percent pure, the vehicle’s A/C system should not be serviced with specialized equipment. Constantly refer to the manufacturer’s accuse for ideal use the the refrigerant analyzer.

NOTE: For more information regarding refrigerant pollution or handle locations, call the environmental Protection agency (EPA) hotline at 800-296-1996 or over the web at www.EPA.GOV/ozone.

Excess air in the Refrigerant

If the recovery/recycling equipment is not provided properly, wait can get in the system and contaminate the refrigerant. Equipment with an automatically air purge normally keeps the air contamination level at much less than 2 percent through weight, which is considered acceptable. However, recycling tools with a manually operated purge can allow high levels of air right into the device usually because of technician error. Recovery/recycling equipment that has actually a manual air purge need to be confirm every day prior to the recycled refrigerant is used. If the container press is not checked, air will certainly transfer right into the system.

Air can also be included during the refrigerant recovery procedure from system and also service water tap leaks. Recovery tools that has actually an automatic shutoff at a predetermined vacuum level will certainly not reach that level if a leak exists. The recovery unit will continue to operate, illustration in wait from the leak resource and including it to the warehouse tank. If the restore unit has a effectively operating automatic purge, normally it will certainly vent the excess air. If the waiting is not eliminated from the system, the system will have performance problems.


To perform top-quality A/C work, you will need to recognize if a container of recycled refrigerant is tainted v air. One means is to to compare the pressure of the recycle refrigerant container with the push of a pure refrigerant container in ~ a well-known temperature. If both pressures room equal, the refrigerant is thought about acceptable.

Use of ideal Lubricants

PAG Oils

Synthetic-based PAG oil are provided with R-134a systems. PAG oils have actually a high hygroscopicity, which means they readily absorb moisture and retain the much much easier than mineral oil. Constantly tightly lid all PAG oil containers after each use.

There are numerous PAG oils v special additive packages and also different viscosities, i beg your pardon are supplied in existing Nissan and Infiniti vehicles, depending upon the form of compressor used. It is essential to usage the correct oil for the type of compressor gift serviced. Because that vehicle details information, describe the appropriate Service manual or the vehicle’s A/C decal.

It is an extremely important to have the exactly amount the oil in the A/C system. This not only enables the system to operate effectively but also ensures ideal lubrication of the compressor. Too small oil will damage the compressor. Too lot oil will alleviate the cooling volume of the system.

If there has been one oil ns for any reason, repair the cause of oil loss and also refill according to the Refrigerant Oil Capacities chart in the service Manual for the automobile being serviced.


NOTE: Refrigerant oils (PAG lubricants) are available through the NissanMaintenance benefit program. Walk to www.NNAnet.com and click top top the “Maintenance Advantage” link.

Diagnosis and also Repair that Under Hood Components

Leak Test

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

Any time more than 0.5 lb. (0.23 kg) that refrigerant is forced to fee the system over a duration of a year, a leak is present. Leakage deserve to usually it is in traced to loose fittings, deteriorated hoses or seals, or damaged steel lines. Plenty of leaks are the an outcome of normal engine vibration, which ease fittings and also may lead to metal fatigue and cracks on metal lines over a duration of time. In any case, these components must be repaired or replaced to prevent extr refrigerant loss.


Many refrigerant leaks can be found through a straightforward visual inspection. While tiny leaks of a few ounces that refrigerant per year are challenging to detect, larger leaks of about a pound per year can conveniently be isolated. This is because these huge leaks might sometimes leaving the system fully empty. If this is the case, very first inspect the mechanism for damaged hoses or feather lock couplings before performing a leak test.

During the visual inspection, be certain to examine the company fittings after removing the gauges. Oil, stains or dust are great indications that a leak. Inspect the bottom of the evaporator housing for oil, due to the fact that oil often accumulates there when the evaporator fails. Check for hose leaks and also porous or worn tubing.

If the intuitive inspection fails to reveal the source of a refrigerant leak, test the mechanism using one of two people an electronic leak detector or a map dye.

You might be forced to include up to a lb of refrigerant in bespeak to find the leak. To locate the source of a huge leak, hear for a hissing sound or spray some soapy water ~ above components and look because that bubbles.

To execute the leak test, the mechanism must it is in under pressure. If the suction line is cold with the mechanism operating, there is usually enough refrigerant in the system to execute the leak test. If not, refrigerant pressure can be provided from a charging terminal although that is not necessary to totally charge a system for leak testing.


Electronic Leak Detection

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

Electronic leak detectors must fulfill or exceed SAE J1627 to operate properly ~ above R-134a. You should also be mindful that there room different species of electronic leak detectors.


Some that the more common species available this day are established by the complying with classifications:

boil anode Heated solid electrolyte Corona suppression

Each kind has advantages and disadvantages, i m sorry is why it is so essential to monitor the manufacturer’s operation instructions. Regardless of which type you have, all of them need some kind of periodic maintenance to execute accurately.

One the the services of using digital leak detection is being able come detect leaks at the time of A/C service. This reduces both refrigerant loss and time associated as in the situation of trace dye.

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


To uncover a leak v an digital leak detector:

1. Start the engine and turn top top the A/C system. Let the mechanism operate for 5 minutes.

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

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

4. Find for leaks by gradually moving the sensor reminder over all system components, consisting of controls, seals and fittings.

5. The tester will emit a sound once the sensing reminder detects refrigerant gases. Most electronic testers have a thumbwheel to readjust detection sensitivity.

NOTE: girlfriend may need to increase the detection sensitivity of the sensing guideline itself. Check out the tester documentation for this procedure.

Trace Dye Test

Trace dye come in different forms for a range of fluids including: engine oil, transmission oil and also engine coolant. Over there are also different types used in A/C service; therefore, that is really important the you usage the exactly type. Trace dye is blended with a small amount the refrigerant lubricant. Compressor manufacturers are really concerned around the addition of lubricants various other than those mentioned on the vehicle’s label. This likewise applies to trace dye; therefore, only use map dye that meets or above Nissan or Infiniti approval.

NOTE: every Nissan vehicles space originally developed with refrigerant map dye (usually a pellet inserted in the Rec. Drier/liquid tank).

The J-43926 Air air conditioning Dye Kit offers you through a technique for adding trace dye come the A/C system. However, adding more than stated to the A/C mechanism will no make the leaks an ext obvious. In fact, adding too lot may cause the A/C system lubricant additives and also viscosity to break down.


As you go over the system, making use of the black light to inspect for indications of map dye, perform not forget to check the evaporator condensate drain. Any trace dye coming out of this place is a sure authorize of one evaporator leak. On part vehicles, friend may have the ability to view the evaporator surface with the black light by removing the fin probe assembly. A possibility exists that a little leak may occur without any signs of map dye. Remember that the lubricant transports map dye, and also if the lubricant never ever reaches a leak source, no visual indications will certainly be present. This is one more reason why you still should use an electronic leak detector.

Finally, constantly attach the map dye identification sticker in the engine compartment close come the A/C decal. This will inform other technicians that the device is already equipped with trace dye to protect against excessive quantities in the lubricant. Throughout the black light inspection if signs of map dye to be evident and the leak source was repaired, you would have to clean the area utilizing the proper trace dye clean solution. This will get rid of confusion about any leaks in the future.

NOTE: map dye is combined with the PAG lubrication oil. The dye should circulate through the whole system before it will reach the source of the leak. Therefore, friend must enable enough time for dye to circulate.

NOTE: Too lot dye can affect the viscosity the the refrigerant oil.

NOTE: always wear the security eyeglasses that come with your black color light equipment. This will boost the luminescence that the dye, which will certainly make the smaller sized leaks much more apparent. More importantly, the eyeglasses defend your eyes from damaging ultraviolet light.

Follow this guidelines when you use map dye to detect leaks:

1. Add minimal quantities of trace dye come the A/C mechanism according come the dye manufacturer’s directions.

2. Operate the A/C device for 5-10 minutes to circulate the dye throughout the system.

3. Bright an ultraviolet desk lamp on the A/C system and look for traces of dye, indicating leaks.

4. Although big leaks will display up quickly, little leaks might take several days to show up using this method. For additional information top top this technique of leak detection, refer to the instructions listed with the dye.


Manifold Gauge analysis Evaluation

Now that you are familiar with some diagnostic trial and error methods, it is time come evaluate several of the an ext common diagnostic scenarios you may encounter. Once it comes to refrigerant device problems, you will require to be able to make a diagnosis based upon pressure gauge readings. There are likewise a few techniques the will assist confirm your suspicions about those push gauge readings.


Before girlfriend make any kind of determination concerning the press gauge readings, you need to consider the company port locations. Remember, these space the areas on the device where your gauges actually monitor the pressure. Gauge readings may not constantly indicate the same press throughout the entire high side or short side that the system. You could have a low-pressure analysis on the high-side gauge and also still have a border on the high-pressure next of the system. If the border is located prior to the high-side business port, your readings will certainly be reduced than normal.

For example, if the high-side business port is situated on the liquid tank and the hose between the condenser and also the liquid tank is restricted, her gauge readings will be lower than you might expect.

By reading the gauges alone, you might be misled right into making one inaccurate diagnosis. Consider all the factors, consisting of ambient temperature, condenser airflow, engine rpm and humidity, which all impact the manifold gauge readings. When you doubt a problem, shot using the hand-feel temperature test on the lines and also hoses to discover restrictions in the refrigerant system. It is in careful; high-pressure refrigerant lines might become an extremely hot!

Place a temperature gauge in one of the wait outlets in the passenger compartment. Ar a second temperature gauge in ~ the condenser to measure ambient (outside) air temperature. Both temperatures room usually necessary to analyze system performance.


Read the push gauges and also compare lock to manufacturing facility specifications. Keep in mind that press gauge readings vary through ambient wait temperature, humidity and system design.

With an approximately temperature the 70° F (21° C), one orifice tube device with a to ride bicycle switch should have approximately 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 press gauge readings are not within manufacturing facility specifications, over there is a trouble in the system. You should use these readings, various other symptoms, the business Manual and your expertise of system operation to uncover the trouble v the system.