Air Conditioning, AC, Heater Troubleshooting, and Diagnosis for Nissan Skyline GT-R

Old cars.  R32, R33, and R34 Nissan Skyline are old cars. 25, 27, maybe 30 years old by the time you get around to needing this guide. Parts don't last forever.   The cars all used R12 refrigerant, which you know is harder to get than legal cocaine. R12 has been phased out of the US since 1996. It was replaced with R134a, which now seems like it might also be ending life on earth, so something new will probably be the latest greatest refrigerant that doesn't kill everyone in a week.

R32 GT-R A/C control panel pulled out of the dash. 

A/C systems are fairly complex, as they have a lot of parts. They are mechanical, electronic, and they have gases under high pressure.  They really aren't for the novice to automotive repair.  Generally we would recommend taking the car to an A/C repair shop to discharge, or recharge the system. While the Nissan Skyline may never have been sold in the US, the parts of the system are very similar to other models sold in the US.

R12 fill. 0.75-0.85kg for R32

R33 GT-R R134a fill, and recommended oil for AC

R34 GT-R R134a fill, and recommended oil for AC

Diagnosis

The first thing to try, is just cycling the unit. Turn it on, go from heat, to A/C and change the recirc settings. See if this frees anything up. Sometimes the doors stick, and just cycling it will help to make everything work again.

Check Fuses.

A/C Clutch fuse is 10A top row, 4th from right R32 GT-R

After that, there is a way to put the A/C into diagnostic mode.  What you do is hold down the OFF button on the A/C unit while starting the car. Continue to hold the OFF button down, until all the lights on the A/C unit light up. It is now in diagnostic mode. If you let it go early, you have to turn car off, and try again.

The flowchart

For complete troubleshooting, download the R32 service manual, and hit up the HA section.

GT-R Groan

Does it sound like you have a monster in your dash?  Do you have to explain what is going on when cycling though A/C or heater settings?

It is probably this A/C mode actuator. The gears in the unit get worn out, and they emit a pretty bad sound. There are several available on ebay here.

This same actuator is used on nearly all the R32s, 2 and 4 doors.  Also S13 88 up. B13 92 up. J30 88 up. Etc

27731-53E00

Blend Door Actuator or Air Mix

27730-01U00 - Actuator Air Intake Box - Early cars

27730-01U00 Actuator Air Intake Box - Early 2 and 4 door. Including GT-R

27742-77S60 - Actuator Air Mix

This one also looks like it works with early cars. Including GT-R

New A/C Compressor for Nissan Skyline GT-R

Brand new R32 GT-R R12 A/C compressor

If your A/C is blowing fuse #5, it probably has a bad A/C compressor clutch. If you need a new compressor, they are available here.

92600-05U14 Compressor - cooler - R32 GT-R

         92600-RHR20 Replaces # 92600-05U14, 92600-05U10

92600-24U07 Compressor - cooler R33 GT-R

92600-AA301 Compressor - cooler R34 GT-R

Condensor, compressor, lines, dryer, and other parts. via FAST

Evaporator, located inside car, behind glovebox via FAST

Expansion Valve

A 1990 Nissan 240SX expansion valve works.

An expansion valve is an AC component that is commonly found on many road going vehicles. It is usually installed at the evaporator inlet and works together with the orifice tube to regulate the flow of refrigerant through the vehicle’s AC system. Too much refrigerant flow and the evaporator core will freeze over; too little and the evaporator core will overheat and compromise the efficiency of the AC system. The expansion valve meters refrigerant flow according to evaporator temperature and the load and cooling demand of the AC system.

Conversion of R32 GT-R from R12 to R134a.

This is the cheap and dirty way to do it. A much better and more expensive way is to replace all the hard parts, condenser, compressor, and recharge with R134a.

Old A/C dryer

The old oil in the system needs to be flushed as it is not compatible with R134a oil

Old dryer replaced with R12/R134a compatible part

O-ring replaced

R134a high pressure fitting replaced

O-rings replaced

O-rings replaced

O-ring replaced

Per a suggestion from Sean Kirby, also clean off/out your evaporator. Great advice to get the most out of the system. Old cars, old systems. 

R134 A/C manifold for filling, extraction, and testing pressures. 

1. All the old refrigerant needs to be removed. 
2. Then flush the old oil and any contaminants out of the system. 
3. Replace all the old o-rings with R134a compatible o-rings.  
4. Vacuum the system, this step really helps with cooling. 
5. Fill the system with recommended amounts of oil, and R134a
6. R134a runs at higher pressure than R12
7. R134a will generally not cool as well as R12 on a converted, non OEM, setup

 R134a conversion

Proper R134a conversion

First step is determining the current gas in the system. If the system is R134a, or R12. Just because there are not R134a fittings on the system, does not mean one of the importers did not fill it to make it cold....then pull the fitting. I have seen no change of fittings, one fitting, and proper conversions. 

Next is to get the gas removed, and remove the evaporator assy. Drop glovebox, remove cross bar, remove 5 screws, and 3 electrical connectors at the top. Once removed, open the box. There are screws around the edge, and 2 clips holding the box together. clips are hidden under the foam insulation. once exposed, insert a flat tip screwdriver into the top of the clip, and pry up, DO NOT put the screwdriver through the side and try to pry, as the clip will actually exerrt more pressure and crack the housing. Seperate the 2 halves and clean out the evaporator core. You should replace the metering valve (240sx will work) Take care not to twist the wire for the suction temp sensor attached to the low pressure line. Using A/C flush, blow out all oil residue from the evap core. Assemble everything in reverse, using green o-rings (240sx kit will work) 

Condenser needs to be disconnected at front fitting, and at receiver drier, and flushed as well. Replace o-rings with green units.

Replace receiver drier, do not pull plugs/fitting caps off of drier until just prior to installation. Again, green o-rings. Take car not to twist low pressure switch wires from old unit, when removing, and when installing on new drier. 

Install fittings. 

Vacuum system for a minimum of 1 hour. This will help to pull any residual oils and moisture from the system. original oil in system was mineral oil, you need to replace with 4oz PAG oil. Factory Zexel DCW compressors require PAG46. Factory R12 charge was 950 grams +/- 50 grams. An R134a charge is 80% of the R12 charge. A good starting point is 1.2 lbs of R134a. 

Start car and monitor gauges. There are no exact pressures you will see on the system, and pressure is based on ambient temps. There are many charts online to follow based on this. 

Rule of thumb, you should have the system on, windows down halfway, on normal A/C and output at the center vents on high fan should be 30° lower than ambient temps. Adjust/fill as needed. 

I do not suggest using the cans you can get at the local parts store that come with the nozzle and you just plug into the low side fitting then pull a trigger. I also do not recommend using anything other than pure R134a. 

If you do not have access to the above, leave it to a shop to vacuum down and fill. Skipping these recommendations will result in poor performance, leaks, or compressor failure.

There are some other options, R12 substitute. Traveling to Mexico to get R12 on the black market. Living without A/C.  2 at 65 A/C - cooling.  Over time, we will add some of those other options here. Some cars don't have the auto amplifier A/C heater unit, but those are pretty rare. 

Cleaning interior air temperature sensor

This sensor is often left disconnected when someone works on the radio or triple meter in a car. Check and clean the interior air temperature sensor, when cleaning the evaporator.  We just happened to have a center radio trim on the work bench, pulled the air sensor off, and cleaned it out with a small brush and some mass air flow sensor cleaner. 

Lots of crap inside the sensor assembly

Look at all that fuzz. 

Cleaned out with mass air flow sensor cleaner. 

Nissan R32 Skyline evaporator removal and refresh project *AMENDED

Frenchys Performance Garage

With more and more parts becoming obsolete and hard to find, we have decided to offer a more modern R134A A/C compressor for the RB engines. This compressor replacement kit will fit all RB engines, and use a Denso SCS06C compressor found on Toyota Echo 1999-2005 models. We can supply the compressor or you can buy it locally to save on shipping. Those units are available from many automotive suppliers and online sellers. 

The compressor is a lot more compact than the OEM unit, and offer a lot more room for aftermarket turbo setups.

The FPG kit comes with:

-Billet aluminum mounting bracket with cnc machined spacers and surfaces for accurate positioning

-Custom made FPG belt tensioner, with precision ground shaft, machined spacer and high tensile hardware for reliability

-Pad style hose ends to suit the compressor. The factory hoses will need to be modified and crimped by a qualified technician.

Belt required will be shorter than your current one. Length will be affected by the balancer you are using. Known belt sizes:

OEM balancer 4PK860

Large ATI Balancer 4PK910

Small ATI Balancer 4PK850

FluidDampr Balancer 4PK860

There are a couple of versions of the FPG kit. One is just a compressor as above, and they also sell a complete kit. 

FPG Nissan Skyline R32 R33 R34 C34 Stagea A/C Air Conditioning Replacement Kit R134A FPG-039
Regular price $2070

-No drilling, no cutting, no pulling half the car apart!

-This kit covers the system from the firewall fittings forward. No under-dash or electronic components are included. It will fit and work with the OEM evaporator. Make sure your evaporator and Tx valve are clean and in good working order.

-Billet aluminium compressor mounting bracket and spacers, high tensile hardware

-Compact, Denso compressor (Found on Toyota Echo 1999-2005) with side mounted lines, ideal for big turbo setups and twin gate manifolds requiring more space

-Fits all RB combinations (20, 25, 26, 30, 25/30, 26/30..!)

-New custom made tensioner for accurate belt alignment and tension

-CNC machined ends and shaped hardlines to relocate the rubber hoses away from the hot areas

-Smaller OD hoses for a cleaner and more compact look, quality USA made fittings that are easy to crimp on (all R134A approved components, lines will come assembled in the kit)

-SPAL 11" Pusher fan, providing more cooling performance and more space for bigger intercoolers. will fit 6" thick intercoolers, and pushes a lot more air than the old fans do.

-Built-in dryer allowing plenty of space for steering cooler and/or extra oil coolers at the front. Dryer element can be replaced/serviced.

-Trinary pressure switch protecting the system from over pressure and loss of gas. Mid point allows the fan to be triggered automatically.

****The Stagea and R34 (non GTR) use a 3 wire pressure sensor and will need to be reused. If your car has a 4 wire pressure switch (R33 and R34GTR) you can also reuse your pressure switch or order a new one with your kit (link to purchase here). The R32 will need a 4 wire pressure switch and is automatically included in the kit****

-The system will need the "Ambient Temperature" sensor to remain installed. It is usually located on the factory fan frame, or on the radiator support. If you do not plug it back in, the climate control unit will not send the a/c request to the engine ECU. (This is a common mistake made by installers and can save you a lot of time trying to fault find).

-Modern multi-flow condenser, smaller footprint with better performance mounted in a custom made aluminium frame

-Custom made fittings for an easy install and reliable setup

-Charge ports are easy to access and away from the hot areas

-Will work with all balancer types, and it is recommended to not engage the compressor clutch at higher rpms (engine ecu triggers the a/c clutch) for component longevity on overdrive balancers. Set up a table in the ecu to control those parameters 

-Diagram below (also located in the "instructions" section of the website) is to add the fan wiring relay to the R32. The later models (33 and 34) will use the factory fan wiring as it is already there.

-We've made the compressor available as an add-on as it may be beneficial for the customer to purchase it locally to save on freight and for manufacturer's warranty. We cannot warrant components that we do not make.

-This system needs to be checked and charged by a licensed professional as per your country's rules and regulations. The system takes around 550g or R134A, but your installer's experience and tooling will confirm what is required.

-Belt size will depend on your balancer and engine model. OEM RB26 balancer will use a 4PK860. Other known belt sizes are:

Large (1000hp) ATI Balancer 4PK910

Small (500hp) ATI Balancer 4PK850

FluidDampr Balancer 4PK860

Buy USA Legal R32 Skylines at Importavehicle.com!
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