the A/C Compressor is a device that compresses refrigerant in the air conditioning system. It is one of the major components in the A/C system.
The Compressor is used to compress refrigerant in the A/C system. The condenser then removes heat from the refrigerant before it is re-expanded into the evaporator. The expansion cools the evaporator, providing cool air to occupants in the car. Refrigerant is then returned to the compressor.
A/C compressors are interchangeable with their respective generations. That is, all R12 compressors are interchangeable with one another, and all R134A compressors are interchangeable with one another–TT and NA doesn’t make a difference (though there are other differences).
Z32 A/C Compressors are quite robust from the factory, so much so that R12 compressors will happily provide years of service after conversion. However, failure is not impossible. Faulty compressors will lead to less-than-adequate cooling (by fault of inadequate refrigerant compression and circulation), and can even fail catastrophically if over-pressurized.
The compressor clutch is another common point of failure, as it operates in quite tight tolerances.
Replacing the A/C compressor should only be done after any refrigerant in the system has been completely and properly evacuated from the system. For more precautions regarding this, see the AC Recharge article.
- 10mm, 12mm, and 14mm sockets and wrenches.
- Assorted socket extensions.
- 14mm crow’s foot.
- Flat-heat screwdriver.
- Jack and safety stands.
- Replacement A/C Compressor (duh)
- New O-rings for the lines that meet the compressor.
- A new drive belt wouldn’t be a bad idea.
Preparation & Initial Steps
- Lift the front of the car into the air and support it safely on jack stands. For more information, see the Jacking Up the Z article.
- Remove the under-belly (if applicable) that covers the underside of the engine. Removal of the front splash shield isn’t necessary.
- Remove the 2x 10mm (or 4x 10mm in airbag-equipped Zs) bolts securing the nose panel to the car. Remove the nose panel.
- Remove the throttle body intake hose (TTs). It may not be necessary to remove the accordion hose on an NA, but feel free if it helps you.
Radiator & Fan Assembly
- Drain the radiator into a bucket or pan by either removing the lower radiator hose or the drain plug on the passenger side.
- Remove the upper and lower radiator hoses.
- Remove the 2x 10mm bolts securing the radiator brackets to the chassis.
- Remove the radiator& shroud as one unit from the vehicle.
- If you’re running a larger aftermarket radiator or simply have trouble with the stock one, go ahead and remove the shroud from the radiator before removal.
- Remove the 4x 10mm bolts holding the fan clutch to the water pump pulley. Carefully remove the fan & clutch assembly, making sure the pulley doesn’t jump off the studs on the water pump. If this does happen, go ahead and loosen the alternator adjustment bracket so you can replace it later.
A/C Belt Tensioner
- Loosen the 12mm bolt on the front of the A/C belt tensioner.
- Loosen the 12mm bolt on the bottom of the A/C belt tensioner to relieve stress on the A/C belt. You can leave the belt on the crank pulley unless you’re replacing it–no need to remove the power steering belt.
- Remove the A/C belt tensioner pulley; you can leave the rest of the tensioner assembly in place. We just need to get the pulley out of the way.
- Located on the top of the compressor (conveniently towards the very back) are two 12mm nuts securing the A/C lines to the compressor, as you can see in the picture at the top of this page. Remove these nuts.
- The mounting points & studs for these nuts are set at a slight angle towards the front of the car which approximately matches the angle at which most box-wrench (ring spanner) heads are set. This means that when you place the wrench on the nut, the wrench handle will be parallel with the top of the compressor (assuming your wrench has such an angle on the head).
- It is likely impossible to fit a socket or even ratcheting wrench over the nuts as they are quite close to the pipes.
- Remove these A/C lines from the fittings and studs. If you can’t get them all the way off, proceed to the next section (Compressor Removal) and get them loose once the compressor is loose.
- Disconnect the electrical connector going to the compressor (it’s a single-wire white connector).
- Remove the 14mm bolt at the front of the A/C compressor securing it to the engine.
- Using an extension and a crow’s foot, remove the 14mm bolt at the rear of the A/C compressor securing it to the engine.
- Remember, this is screwed in from the back. If you’re facing the compressor, you’ll have to turn it clockwise to loosen it. It can be kind of confusing, but just imagine you were standing behind the compressor removing this bolt.
- Remove the 2x 14mm bolts on the underside of the A/C compressor.
- You should now be able to jiggle the compressor loose slightly. If you haven’t already, now is a good time to fully remove those A/C lines from the compressor (leave them connected elsewhere).
- Wiggle the compressor out and remove it through the top of the engine bay.
Note: If storing a good A/C compressor, store it in the same orientation as it would be installed, and plug the ports on it.
Installation is mostly the reverse of the removal, with a few things to note.
- When installing the A/C lines on the compressor, install new o-rings with a small amount of compressor lubricant (Ester [R12] or PAG [R134A] oil).
- It’s a good idea to connect the A/C compressor lines to the compressor (or at least get them over the studs) before you fully mount the compressor.
- The four compressor mounting bolts are to be torqued to 37-50 ft-lbs.
- The front idler pulley bolt is to be torqued to 23 ft-lbs.
The compressor requires a small amount of oil for lubricant. This flows through the system with the refrigerant. When replacing the compressor (or any component in the A/C system) it’s often necessary to add some oil to compensate for what’s lost in the old part.
For more information, see the Compressor Oil section of the main Air Conditioning System article.