AC Compressor & Condenser Replacement

Section 0 — Overview & Safety Warnings

What We're Replacing

This guide covers the complete replacement of:

• AC Compressor — the pump that pressurizes the refrigerant
• Condenser — the radiator-like unit in front of the engine radiator that cools the hot refrigerant gas
• Receiver/Drier — a filter/dryer canister that removes moisture and debris (integrated into our replacement condenser)
• O-rings — all seals at every refrigerant connection point (reusing old O-rings = guaranteed leaks)

Why Replace All At Once?

When an AC compressor fails, it often sends metal debris throughout the system. If you only replace the compressor, that debris will circulate and destroy the new one. Replacing the condenser and receiver/drier removes the main contamination points. Most compressor warranties also require replacement of the receiver/drier and O-rings.

Key Specifications

Section 1 — Parts List

Order all parts before starting. Having everything on hand avoids leaving the system open to moisture while waiting for deliveries.

Section 2 — Tools Required

AC-Specific Tools

Vehicle Lifting

Standard Hand Tools

• Socket set: 10mm, 12mm, 14mm sockets + ratchet + extensions (both 1/4" and 3/8" drive recommended)
• Torque wrench: Covers 5–26 Nm (4–19 ft-lb) range
• Combination wrenches: 10mm, 12mm, 14mm
• Pliers: Standard and needle-nose
• Flathead & Phillips screwdrivers
• Breaker bar or long ratchet + 15mm or 19mm socket (for the serpentine belt tensioner)
• Trim removal tools / plastic pry bars (for clips and push-pins)

Miscellaneous

• Drain pans (2) — one for coolant, one for compressor oil
• Caps/plugs for open refrigerant fittings (or clean rags + zip ties as temporary seals)
• Clean measuring cup (for compressor oil transfer)
• Paper towels / shop rags
• Permanent marker / masking tape (for labeling connectors and hoses)
• Phone/camera (take photos before disassembly!)

Section 3 — Preparation

1. Park on a flat, level surface — concrete driveway or garage floor is ideal. Avoid gravel, grass, or slopes.
2. Engage the parking brake and place wheel chocks behind both rear wheels.
3. Let the engine cool completely — ideally let the car sit for 2+ hours, or overnight. You'll be draining coolant and don't want to get burned.
4. Disconnect the negative battery cable using a 10mm wrench. The negative terminal is marked with a “−” symbol and typically has a black cable. Tuck the cable away so it can't accidentally touch the terminal. Wait at least 1 minute before proceeding.
5. Gather all parts and tools — lay them out organized. Nothing worse than realizing you're missing a part with everything disassembled.
6. Take photos of everything before you start removing anything:
   • Serpentine belt routing (there may also be a sticker diagram in the engine bay)
   • All hose and connector locations
   • Wiring harness routing
   • AC line connections
   • Bumper fastener locations

Section 3.5 — Refrigerant Recovery (DIY)

Before you can open any refrigerant line, you must first recover all the R-134a from the system. Venting refrigerant to the atmosphere is illegal and carries severe fines.

What You Need: AC Recovery Machine (~$300–500)

A recovery machine is a self-contained unit with its own compressor, storage tank, filter, and gauges. It pumps refrigerant out of your car's AC system and stores it for reuse or recycling. This is the standard way to do it — straightforward, reliable, and fast.

Other brands: Robinair, YellowJacket, Mastercool (~$200–400 for recovery-only units).
Alternative: Check local tool rental shops, or buy a used unit on eBay/Facebook Marketplace.

Understanding Your Manifold Gauge Set

If this is your first time using manifold gauges, here's what you're looking at:

• Blue gauge (left) — reads low-side pressure. The scale goes from vacuum (below 0) up to ~120 psi. During normal AC operation, this reads 25–45 psi.
• Red gauge (right) — reads high-side pressure. The scale goes up to ~500 psi. During normal operation, this reads 150–250 psi.
• Blue hose — connects to the low-pressure service port on the car (larger fitting, usually near the firewall on the suction line, often has a blue or black cap).
• Red hose — connects to the high-pressure service port on the car (smaller fitting, usually near the condenser at the front, often has a red cap).
• Yellow hose (center) — connects to the service equipment: the recovery machine, vacuum pump, or refrigerant can depending on the step.
• Blue valve knob (left) — opens/closes the path between the low-side hose and the center hose.
• Red valve knob (right) — opens/closes the path between the high-side hose and the center hose.

Key concept: The gauges always show pressure regardless of whether the valves are open or closed. The valves only control whether refrigerant can flow through the center hose. So you can monitor both pressures with both valves closed.

Locating the Service Ports

1. Open the hood and look for two small metal tubes with threaded caps, each about the size of a tire valve stem.
2. Low-side port: On the larger-diameter suction line, typically near the firewall (back of engine bay) on the passenger side. The quick-connect coupler on your blue hose will only fit this port.
3. High-side port: On the smaller-diameter discharge line, typically near the condenser (front of engine bay). The quick-connect coupler on your red hose will only fit this port.
4. The fittings are different sizes on purpose — you physically cannot connect the wrong hose to the wrong port.

Recovery Procedure

1. Make sure the engine is OFF and the AC is off.
2. Remove the protective caps from both service ports.
3. Connect the blue hose to the low-side port — pull back the collar on the quick-connect coupler, push it onto the port, then release the collar. It should click and lock on.
4. Connect the red hose to the high-side port — same procedure.
5. Connect the yellow (center) hose to the recovery machine's inlet fitting.
6. Before opening any valves, read both gauges. A working system will show some static pressure (typically 70–100 psi on both sides when the engine is off and temperatures are moderate). If both gauges read 0, the system is already empty.
7. Open both manifold valves (turn the blue and red knobs counterclockwise).
8. Turn on the recovery machine — it will pull refrigerant out of the vehicle through both ports and store it in its internal tank.
9. Let it run until the machine auto-shuts off (system pressure reaches ~0 psi or a slight vacuum).
10. Close both manifold valves. Wait 5 minutes, then check if the pressure rises on your gauges. If it rises above 0 psi, open the valves and run the machine again — some refrigerant was trapped in the oil/lines and is slowly releasing.
11. Repeat until pressure holds steady at 0 psi for 5 minutes.
12. Close both valves and turn off the machine. Leave the hoses connected if you're proceeding with work immediately, or disconnect and cap the ports.

Section 4 — Remove Aerodynamic Under Cover

Workshop Manual Reference: 09-16-32

The aerodynamic under cover is the large plastic shield that covers the underside of the engine bay. It must be removed to access the compressor from below.

Raising the Vehicle

You need to get under the front of the car. You have two options:

• Option 1: Drive-on ramps — easiest if you have them. Drive front wheels up, set parking brake, chock rear wheels.
• Option 2: Floor jack + jack stands:
  1. Place wheel chocks behind both rear wheels.
  2. Position the floor jack under the front crossmember (the large metal beam running left-to-right behind the front bumper).
  3. Jack up the front of the car until you have comfortable working space underneath (~12–18 inches).
  4. Place jack stands under the front pinch welds (the reinforced seam running along the bottom edge of the body, just behind each front wheel). The owner's manual shows these locations.
  5. Lower the car onto the jack stands. Wiggle the car to confirm it's stable before getting underneath.

Under Cover Removal Steps

1. Remove screws A — multiple small Phillips-head screws along the front edge of the cover.
2. Remove bolts B — 3 bolts (torque spec: 4.5–7 Nm / 40–62 in-lbf). Use a 10mm socket.
3. Remove fasteners C — these are push-pin clips (also called "Christmas tree clips"). To remove them:
   • Use a trim removal tool or flathead screwdriver
   • Pry up the center pin first (it pops up about 3mm)
   • Then pull the entire clip out
   • Be gentle — these clips are reusable but break easily
4. Pull the under cover straight down and set it aside.

Section 5 — Remove Splash Shield

Workshop Manual Reference: 09-16-36

The front splash shields are the plastic panels inside each front wheel well. You may need to remove them (or at least fold them back) for better access to the compressor and condenser area.

1. Turn the steering wheel to one side to expose the inner fender area.
2. Remove screws A, screw B, and fastener C — as shown in the diagram.
3. Pull the splash shield free and set aside.
4. Repeat on the other side if needed.

Section 6 — AC Compressor Removal

Workshop Manual Reference: 07-11-26

Step 6a — Drive Belt Removal (2.5L Procedure)

The 2.5L engine uses a single serpentine belt that drives everything: alternator, AC compressor, water pump, and idler pulleys. It has an automatic spring-loaded tensioner — no manual tension adjustment needed. To remove the belt, you simply release the tensioner.

1. Before touching the belt, photograph the belt routing. There may be a routing diagram on a sticker in the engine bay (radiator support or underside of the hood). If not, use the diagram below and photograph yours from the front of the engine for reference.
2. Locate the automatic belt tensioner (#1 in the diagram below) — it's a small pulley on a spring-loaded arm, lower-left area of the belt system.
3. Place a 14mm socket on a breaker bar or long-handle ratchet on the tensioner center bolt.
4. Rotate the tensioner clockwise (toward the front of the car) to release tension on the belt. The tensioner arm will compress against its spring.
5. While holding the tensioner back, slip the belt off the easiest pulley (the tensioner pulley itself or an idler).
6. Slowly release the tensioner arm.
7. Remove the belt completely.

Step 6b — Remove Water Hose Bracket

There's a bracket near the compressor that holds a coolant/water hose in place. Remove the bolt holding this bracket to move the hose out of the way. Simple bolt removal — just moves things aside for clearance.

Step 6c — Disconnect Compressor Electrical Connector & Clip

1. Locate the wire harness clip on the compressor. It's a small retaining clip that holds the wiring harness in place.
2. Remove the clip (squeeze or pry with a small screwdriver).
3. Disconnect the electrical connector: press the locking tab on the connector and pull it straight off. Don't yank on the wires.

Step 6d — Disconnect Refrigerant Lines

There are two refrigerant lines connected to the compressor:

• Cooler hose (HI) — the high-pressure discharge line (smaller diameter, hot during operation)
• Cooler hose (LO) — the low-pressure suction line (larger diameter)

For block joint type connections (most common on the Mazda5):

1. Hold the female side of the block fitting firmly with pliers or a wrench to prevent it from spinning.
2. Remove bolt A (torque spec: 6.9–9.8 Nm / 62–86 in-lbf).
3. Carefully separate the line from the compressor.

For spring lock coupling type connections (if equipped):

1. Insert the spring lock disconnect tool around the line.
2. Push the tool inward to compress the garter spring inside the coupling.
3. While holding the tool in place, pull the male fitting out of the female fitting.

Step 6e — Remove Compressor Mounting Bolts

1. Remove bolt B (and any additional mounting bolts) — torque spec: 18–26 Nm (14–19 ft-lbf). There are typically 3–4 bolts holding the compressor to the engine block/bracket.
2. Support the compressor with one hand as you remove the last bolt — it's heavy (about 10–15 lbs).
3. Carefully lower the compressor out through the bottom of the engine bay (through the space where the under cover was).

Section 7 — Condenser Removal

Workshop Manual Reference: 07-11-28

The condenser sits directly in front of the engine radiator. To remove it, you must remove several components first, then lift the radiator and condenser out together as a unit, then separate them on a workbench.

Step 7a — Remove Plug Hole Plates

Reference: 01-10A-4

These are the plastic/rubber covers on top of the engine that cover the spark plug holes (also called "coil covers" or "engine covers").

1. Simply lift each plate upward — they sit in rubber grommets/clips.
2. No tools needed — just pull firmly upward.
3. Set aside.

Step 7b — Remove Air Cleaner & Fresh Air Duct

Reference: 01-13A-5

The air cleaner assembly (airbox) and its intake ducts need to come out for clearance to access the radiator and condenser.

1. Disconnect the MAF (Mass Air Flow) sensor electrical connector — press the tab and pull.
2. Remove the screws and clips holding the air cleaner cover.
3. Remove the air filter element (good time to inspect/replace it).
4. Remove the bolts holding the air cleaner box to the vehicle.
5. Disconnect and remove the fresh air ducts (the intake tubes that connect the airbox to the throttle body). There are typically two pieces (No.1 and No.2).
6. Set everything aside in order.

Step 7c — Drain Engine Coolant

Reference: 01-12A-4

1. Remove the cooling system cap (on the radiator, typically on the passenger side). Turn it slowly and let any residual pressure release before fully removing. "What's the cooling system cap?" — it's the round cap on top of the radiator filler neck, usually near the upper radiator hose.
2. Place a large drain pan (at least 1 gallon / 4 liter capacity) under the bottom of the radiator.
3. Locate and open the radiator drain plug (petcock). It's at the bottom of the radiator, usually on the driver's side. It looks like a small plastic wingnut or valve.
   • Turn it counterclockwise to open. Some have a small nipple you can attach a hose to for a cleaner drain.
4. Let the coolant drain completely — approximately 3.8 liters will come out. This takes 5–10 minutes.
5. Close the drain plug when finished. Don't leave it open — you'll forget later.

Step 7d — Remove Cooling Fan Assembly

Reference: 01-12A-12

The cooling fan assembly sits between the radiator and the engine. It must come out before you can remove the radiator.

1. Disconnect the cooling fan motor connectors. There are typically 2 fans (No.1 and No.2), each with its own electrical connector. Press the tab and pull.
2. Disconnect the wiring harness from its routing clips.
3. Remove the mounting bolts (various sizes, torque specs range from 2.8–5.0 Nm to 5.9–8.3 Nm depending on the bolt).
4. Remove the cooling fan assembly — it comes out from below the engine compartment (drop it down).

Step 7e — Disconnect Condenser Refrigerant Lines

1. Disconnect the cooler hose (HI) from the condenser — block joint type connection. Same procedure as Step 6d: hold the female side, remove bolt A.
2. Disconnect the cooler pipe from the condenser.
3. Cap or plug the open fittings to keep debris out while you work.

Step 7f — Radiator Removal (with Condenser Attached)

Reference: 01-12A-7

The condenser is hooked onto the front of the radiator via tabs. They come out as a single unit.

1. Remove the cooling system filler neck — unbolt and set aside.
2. Remove the filler hose.
3. Disconnect the upper radiator hose (squeeze the clamp with pliers, slide it back, then pull the hose off).
4. Disconnect the lower radiator hose (same method).
5. Disconnect the automatic transmission cooler lines from the radiator (two metal lines on the lower portion of the radiator). Have a rag ready — some ATF will drip out. These are typically held on with spring clamps or flare nuts.
6. Remove the radiator mounts:
   • These are rubber-mounted brackets at the top of the radiator.
   • Press the tabs inward, then lift the mount upward to release.
7. Carefully lift the radiator + condenser assembly straight up and out of the engine bay. This is a two-person job — have a helper support one side.

Step 7g — Separate Condenser from Radiator

1. Lay the radiator/condenser assembly on a clean, padded surface (cardboard or towels). The condenser is aluminum and dents easily.
2. Look at the lower edge of where the condenser meets the radiator. There are left and right tabs — press them to release.
3. The condenser hooks onto the upper edge of the radiator at left and right insertion points. Lift the condenser upward to unhook it.
4. Set the old condenser aside. Keep the radiator — you'll hook the new condenser onto it later.

Section 8 — Receiver/Drier Removal — Skipped

Our replacement condenser has the receiver/drier integrated (attached directly to the condenser), so there's no need to remove the old standalone receiver/drier or take off the front bumper to access it. The old receiver/drier stays in place behind the bumper — its lines were already disconnected in Step 7e.

Section 9 — Installation (Reassembly)

Now we install the new components. Installation is essentially the reverse of removal, but with some critical steps for the AC system specifically.

Step 9a — Prepare New Compressor (CRITICAL Oil Balancing Procedure)

New compressors come pre-filled with oil, but usually too much for your system. You need to balance the oil amount to match what was in your old system.

1. Take the NEW compressor. Remove the cap from the suction port. Rotate the compressor shaft by hand (using a wrench on the clutch center bolt) 6–8 full revolutions. This pumps oil out of the internal chambers.
2. Pour the oil that comes out into a clean measuring cup. Note the amount. This is the "new compressor oil amount."
3. Take the OLD compressor. Rotate its shaft 6–8 revolutions. Collect that oil in a separate clean container. Note the amount. This is the "old compressor oil amount."
4. Compare:
   • The new compressor should have more oil than what came out of the old one.
   • If the old compressor is seized and you can't rotate the shaft: skip measuring the old one. Instead, drain and measure only the new compressor, then pour back approximately 80–90 ml (roughly 2/3 of the total 120 ml system capacity, since some oil remains distributed in the lines and evaporator).
   • If the old compressor turns but very little oil comes out, that's normal — oil migrates throughout the system during operation.
5. Pour the same amount of oil that came out of the OLD compressor back into the NEW compressor through the suction port. (Or use the 80–90 ml estimate if the old compressor was seized.)
6. Oil type: FD46XG / PAG ISO 46
7. Total sealed system volume: 120 ml (4.06 fl oz)

Step 9b — Install New Condenser onto Radiator

1. Add 35 ml of supplemental PAG 46 oil into the new condenser (pour it into the inlet fitting). This replaces oil that was trapped in the old condenser.
2. With the radiator laying on a flat surface, position the new condenser in front of it.
3. Hook the condenser onto the radiator at the upper left and right insertion points (the condenser hooks over the top edge of the radiator).
4. Press the lower tabs into place until they click/snap.
5. Verify the condenser is firmly attached and aligned with the radiator.

Step 9c — Install Radiator/Condenser Assembly

1. With a helper, lower the radiator (with new condenser) back into the engine bay.
2. Seat the radiator into the shroud panel installation holes at the bottom.
3. Install the radiator mounts:
   • Remember: Arrow must point toward the front of the vehicle!
   • Press tabs inward to lock.
4. Reconnect the lower radiator hose — push on fully, slide clamp back into position.
5. Reconnect the upper radiator hose — same method.
6. Reconnect the ATF cooler lines to the lower portion of the radiator.
7. Reinstall the filler hose and filler neck (bolts: 8–10 Nm).

Step 9d — Reinstall Cooling Fan Assembly

1. Slide the fan assembly up from below into position between the radiator and engine.
2. Install all mounting bolts and torque to spec (2.8–8.3 Nm range, varies by bolt).
3. Reconnect both fan motor connectors (you'll hear a click when they lock).
4. Route the wiring harness back through the original clips.

Step 9f — Install New Compressor

1. Lift the new compressor into position from below.
2. Install mounting bolts B and torque to 18–26 Nm (14–19 ft-lbf). Start all bolts finger-tight first, then torque in a cross pattern.
3. Install new O-rings on both refrigerant line connections. Apply PAG 46 oil.
4. Connect the refrigerant lines and tighten bolt A: 6.9–9.8 Nm.
5. Reconnect the electrical connector (push until it clicks).
6. Reinstall the wiring harness clip — engage to 3 or more teeth to lock.
7. Reinstall the water hose bracket.

Step 9g — Drive Belt Installation (2.5L)

1. Route the belt according to the belt routing diagram below (or from your photo / engine bay sticker). Make sure it wraps around every pulley in the correct pattern — getting this wrong can cause immediate damage.
2. Leave the belt off one pulley (typically the tensioner pulley or an idler).
3. Place the 14mm socket on a breaker bar on the auto-tensioner bolt and rotate clockwise (toward front of car) to release tension.
4. Slip the belt onto the last pulley.
5. Slowly release the tensioner — it will automatically apply the correct tension.
6. Verify: Check that the belt is properly seated in ALL pulley grooves. A misaligned belt will squeal, throw off, or cause damage.
7. Rotate the crankshaft clockwise by hand for 2 full rotations (use a socket on the crankshaft pulley bolt) to verify the belt tracks correctly and doesn't interfere with anything.

Step 9h — Reinstall Remaining Components

1. Air cleaner and fresh air duct — reverse of Step 7b. Reconnect the MAF sensor.
2. Plug hole plates — push down into the rubber grommets.
3. Splash shield — reinstall fasteners (Section 5).
4. Aerodynamic under cover — reinstall fasteners C, bolts B, screws A (Section 4).
5. Reconnect negative battery cable — tighten the 10mm nut securely.

Section 10 — Refill Engine Coolant

Workshop Manual Reference: 01-12A-4

1. Verify the radiator drain plug is closed/tight.
2. Prepare coolant mixture:

   Climate	Coolant %	Water %	Freeze Protection
   Moderate (most US areas)	55%	45%	-37°C / -35°F
   Severe cold	60%	40%	-51°C / -60°F
   Hot climate / no freeze risk	50%	50%	-37°C / -35°F

   Use Mazda FL22 or equivalent long-life coolant. Use distilled water (not tap water) for the mix. Or buy pre-mixed coolant.

3. Pour coolant slowly into the radiator filler neck until the level reaches near the top. Go slowly — air bubbles need time to escape.
4. Fill the coolant reserve tank (the translucent plastic tank with MIN/MAX marks) to the "F" (Full) mark.
5. Install the cooling system cap.
6. Start the engine and let it warm up to operating temperature (the temperature gauge will reach its normal position).
7. Run the engine at 2,500 RPM for 5 minutes. This circulates coolant and helps push air bubbles out.
8. Then: Rev to 3,000 RPM for 5 seconds, then return to idle. Repeat this 3–5 times. This "burping" procedure helps purge trapped air from the system.
9. Turn off the engine and let it cool completely.
10. Check the coolant level again — top up if needed (both radiator and reserve tank).
11. Check for leaks at all hose connections and the drain plug.

Section 11 — Evacuate & Charge AC System

Workshop Manual Reference: 07-10

This is the final step for the AC system. You'll pull a deep vacuum to remove all air and moisture, then charge with the exact amount of R-134a refrigerant.

Step 1: Connect the Manifold Gauge Set

If you used the manifold gauges for recovery in Section 3.5, you're already familiar with the setup. If your recovery machine had its own gauges and you're using a separate gauge set for this step, connect them the same way:

1. Ensure the engine is OFF and both manifold valves are closed (turned fully clockwise).
2. Connect the blue (low-side) hose to the low-pressure service port (larger fitting, near firewall).
3. Connect the red (high-side) hose to the high-pressure service port (smaller fitting, near condenser).
4. Connect the yellow (center) hose to the vacuum pump inlet.
5. Both gauges should currently read at or near 0 psi (since the system is empty after your work).

Step 2: Evacuate the System (Pull a Vacuum)

Why: Even though you recovered the old refrigerant, the system has been open to the atmosphere during the repair. Air and moisture are now inside. A vacuum pump removes all air and boils off any moisture at low pressure — water inside the AC system causes corrosion, ice blockages, and acid formation.

1. Make sure the engine is OFF.
2. Verify the center (yellow) hose is securely connected to the vacuum pump.
3. Open both manifold valves (turn the blue and red knobs counterclockwise). This allows the pump to pull vacuum from both the high and low sides of the system simultaneously.
4. Turn on the vacuum pump.
5. You should immediately see the low-side (blue) gauge needle drop below 0 and begin moving into the vacuum range (the numbers below 0 on the gauge, measured in inches of mercury / inHg).
6. Let it run for at least 30 minutes. If the system was open for more than a few hours or in humid conditions, run for 45–60 minutes.
7. Verify the low-side gauge reads -29.8 inHg or lower (some gauges show this as "30" on the vacuum scale). This confirms a deep vacuum. The high-side gauge may also show vacuum but isn't calibrated for it — focus on the blue gauge.
8. Close both manifold valves (turn clockwise until snug).
9. Turn off the vacuum pump.
10. Wait at least 15 minutes and watch the low-side gauge carefully.

Step 3: Charge with R-134a

What happens during charging: You're going to let pressurized refrigerant from cans flow into the evacuated (vacuum) system. The vacuum pulls the refrigerant in initially. Once the engine is running and the compressor is spinning, the compressor's suction pulls the remaining refrigerant in through the low side.

3a. Connect the Refrigerant

1. Both manifold valves must be CLOSED.
2. Disconnect the yellow center hose from the vacuum pump.
3. Screw a can tap valve onto your R-134a can (if using 12 oz cans). Make sure the tap valve is in the closed position (knob turned all the way out).
4. Connect the yellow center hose to the can tap valve.
5. Turn the can tap knob all the way in to puncture the can, then back it out half a turn to open the flow path.
6. Place the can on your digital scale. Note and record the starting weight (e.g., "can + tap = 428g").

3b. Purge the Center Hose

The center hose is full of air (from disconnecting the vacuum pump). You need to push that air out before opening it to the system:

1. With both manifold valves still CLOSED, slightly loosen the center hose fitting at the manifold (where the yellow hose connects to the gauge body — NOT at the can end).
2. You'll hear a brief hiss as refrigerant pressure from the can pushes air out of the hose.
3. After 2–3 seconds, retighten the fitting. The center hose is now full of refrigerant instead of air.

3c. Initial Charge (Engine OFF)

1. With the engine still OFF, open the low-side (blue) valve only.
2. Refrigerant will flow from the can into the evacuated system. You'll see the low-side gauge rise from vacuum toward a positive pressure. The can will get cold as liquid refrigerant evaporates out of it.
3. Let it flow until the pressure stabilizes and you stop hearing flow (typically 1–3 minutes). The system will equalize around 40–60 psi depending on ambient temperature.
4. Close the low-side valve.

3d. Running Charge (Engine ON)

1. Start the engine.
2. Turn the AC to MAX COLD, fan to MAX speed, set to recirculate mode.
3. The compressor clutch should engage (you may hear a click and see the center of the compressor pulley begin to spin). If it doesn't engage, that's normal — many compressors need a minimum charge before the low-pressure safety switch allows engagement.
4. Open the low-side (blue) valve. Refrigerant will now be pulled in by the compressor's suction.
5. Watch the gauges:
   • Low side should read 25–45 psi during charging (varies with ambient temp and charge level).
   • High side should read 150–250 psi (roughly 2–2.5x the ambient temperature in °F, e.g., 80°F day ≈ 160–200 psi).
6. You can hold the can upside down briefly to let liquid refrigerant flow out faster (liquid charges faster than gas). This is safe on the low side as long as the compressor is running — it will vaporize the liquid before it reaches the compressor.
7. Monitor the scale. When the first can is empty, close the low-side valve, disconnect the empty can, attach a new one, tap it, purge the hose again, and continue.
8. Keep charging until the scale shows a total of 480g (16.9 oz) has been added across all cans.

Step 4: Verify Charge and Disconnect

1. With the full 480g charge in the system and the engine running with AC on MAX:
   • The low-side gauge should read 25–35 psi (depending on ambient temp).
   • The high-side gauge should read 150–250 psi.
   • If the low side is too high (50+ psi), the system may be overcharged or the condenser fans aren't running.
   • If the low side is too low (<20 psi), the system may be undercharged or there's a restriction.
2. Close both manifold valves.
3. Turn off the engine.
4. Disconnect the gauge hoses from the service ports — pull back the quick-connect collar and pull straight off. A small hiss as residual hose pressure releases is normal (this is just the tiny amount trapped in the hose, not a system leak).
5. Reinstall the protective caps on both service ports. Finger-tight is fine.

Section 12 — Final Testing & Verification

1. Start the engine and let it idle at approximately 1,500 RPM (slight throttle or fast idle is fine).
2. Set AC to MAX COLD, fan on MAX HI, recirculate mode, all windows closed.
3. Let the system run for 5–10 minutes to stabilize.
4. Check vent temperature with a thermometer inserted into the center dash vent:
   • Target: 35–45°F (2–7°C) depending on ambient temperature.
   • On a hot day (90°F+), 45–50°F is acceptable.
   • If vent temp is above 55°F, there may be an issue (undercharge, air in system, or a leak).
5. Listen for unusual compressor noises:
   • Clicking/rattling: may indicate debris in the system or a clutch issue.
   • Grinding/squealing: bearing failure or belt issue.
   • Normal sound: a slight hum/drone when the compressor clutch engages.
6. Leak check: Use your electronic leak detector to sniff around every refrigerant connection point (compressor fittings, condenser connections, receiver/drier, service ports).
7. Check coolant level and connections: Look for any drips at radiator hoses, drain plug, and filler neck.
8. Verify cooling fans cycle on: As the AC runs, the condenser fan should be running. The radiator fan should cycle on when coolant temperature rises.
9. Take a test drive: Drive for 15–20 minutes with AC running. Check for consistent cooling. Check under the car when you return — a small puddle of clear water (condensation from the evaporator drain) is normal and expected.

Section 13 — Torque Reference Table

All torque specifications in one place for quick reference during the job.

Section 14 — Video & Web References

Supplementary resources organized by topic. Watch the relevant videos before starting each section to get a visual understanding of the procedures.

AC System — General

Refrigerant Recovery

Evacuation & Charging

Compressor Oil