Hardlymoving writes about do-it-yourself automobile maintenance on various makes and models.
This article shows you how to replace the compressor and condenser on a Honda Pilot (2009 - 2012). The job includes installing new valve stems and evacuating and recharging the AC system. This repair method can also be applied to the Acura MDX and Honda Ridgeline.
Replacing My Customer's Compressor Didn't Fix His AC Problem
My customer had a repair shop replace his AC compressor a month earlier and complained that the AC no longer worked. The repair shop refused to follow up to determine the cause of the failure. I was unable to obtain much history about how the repair was performed.
I inspected the car and saw there was good pressure in the system and the AC fuse wasn't blown. The compressor clutch, however, would not engage.
The customer agreed to a new replacement compressor (provided by him) while I provided a new Denso condenser and low- and high- pressure valve stems, followed by an evacuation and recharge service. I would have preferred the OEM Honda compressor manufactured by Denso since that compressor had lasted over 10 years.
I have seen repair estimates of this type go up to $1,600.00. I can usually perform this repair in under three hours.
Why Replace the Condenser Along With the Compressor?
Although some people think it's unnecessary to replace the condenser as well when the compressor fails, replacing the condenser is recommended by most aftermarket AC compressor providers. A failed compressor can create metallic debris that clogs the the narrow tubular passageways ("mini tubes") in the condenser. This debris will impede refrigerant gas flow and could cause pressure in the compressor to build up higher than normal to overcome the restriction. Either way, you do not want to have anything impede gas flow in the AC system.
In most modern cars, these tubular passageways are too small to pressure clean.
Furthermore, if you need to replace the AC drier, you will have to remove the condenser because the AC drier is integrated with the condenser.
This 21-minute video will provide you with visual step-by-step help for completing the removal and replacement of a Honda Pilot AC compressor and condenser. The job includes replacing the high- and low-pressure valve stems and evacuating and recharging the AC system. The steps are also described lower down in the article.
I. Removing the Upper Radiator Shroud and Chrome Plastic Radiator Grill
To access the AC condenser, you need to remove the upper radiator shroud and the chrome plastic radiator grill that's mounted on top of the bumper.
- Using either a thin-tip screw driver or push-pin pliers, remove the push pins that holds the upper radiator shroud in place. The shroud can now be pulled off.
- Remove the two 10-mm bolts that hold the corners of the plastic radiator grill.
- Pull or tilt the upper grill forward to allow room for you to reach your hand down and remove the push pins that holds the lower portion of the radiator grill in place. The push pins are inverted (that is, mounted and pushed from the bottom up) and may be difficult to pry out the center pin. Use a thin-tip screw driver as a prying tool to get the center pin moving out. Using push-pin pliers would make the job easier.
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II. Removing the AC Compressor
- Wiggle off the coolant reservoir container off of its holder to make room for removing the accessory belt. Place the container away from the work area.
- Remove the accessory belt from the AC compressor by applying clockwise force on the belt tensioner pulley bolt. A long handle box or ratchet wrench is recommended for leverage.
- From underneath the car, remove the push pins from the right corner of the splash guard so you can bend it down and away to expose the AC compressor.
- Remove the cross bracket that blocks the path to the AC compressor. One bolt is a right-corner subframe bolt, and the other two smaller bolts are the front chassis bolts.
- 5. Disconnect the high- and low-pressure connections to the AC compressor. They are held in place with 10-mm bolts plus one bracket bolt that holds the AC line in place.
- Disconnect the one electrical line to the compressor. Pinch and then pull on the electrical fitting to disconnect it.
- Remove the four compressor mounting bolts. Remove the bottom bolts last, so you can control the drop of the compressor when the last bolt is removed.
- Angle the compressor out of the car.
III. Transferring the AC Coupler and Adding Compressor Oil
- Remove the two 5.5-mm bolts that holds the AC coupler to the compressor.
- Replace the O-ring on the coupler with a new O-ring.
- Before transferring the coupler to the new compressor, ensure the compressor has been pre-filled with compressor oil. Most new and rebuilt compressors come pre-filled with new oil. Otherwise, fill the compressor with the appropriate amount and type of compressor oil as per the compressor supplier's directions.
IV. Installing the New Compressor
- Before installing the new compressor, consider removing the upper condenser to compressor hose in order to ease installation of the new O-ring.
- Position the new compressor back on to the engine. There's a lip on the engine to slightly support the bottom portion of the compressor.
- To avoid having to support the compressor by hand, install the bottom two compressor bolts first, then the two upper bolts.
- Torque down the four compressor mounting bolts.
- Connect the electrical line to the compressor.
- Re-install the accessory belt.
- Install the high- and low-pressure AC compressor hoses back on to the compressor. Afterwards, install the compressor bracket.
- Re-install the cross bracket.
V. Removing the AC Condenser
- If not already removed, disconnect the AC hose connected to the corner of the AC condenser.
- Remove the left and right upper condenser support bracket bolts, then detach the brackets from the condenser.
- Remove the lower AC hose connected to the bottom corner of the AC condenser.
- Pull up and remove the condenser.
VI. Installing the New Condenser
- Transfer the rubber bushings at the bottom of the old condenser to the new condenser.
- Replace the O-rings from the upper and lower AC hose to the condenser connectors.
- Position the new condenser back into the car, making sure the bottom mounting rubber bushings are seated into their mounting holes.
- Connect and bolt the upper and lower AC hoses onto the condenser.
- Re-install the upper left and right condenser brackets and bolt the brackets on to the chassis.
Recommendation: After you install the compressor and condenser, you can wait and re-install the chrome radiator grill and bottom dust cover during the half-hour AC evacuation process.
VII. Replacing the Low- and High-Pressure Service Valve Stems
If no pressure leakage has been detected, it's not necessary to replace the valve stems for the service connection ports, but I recommend replacing them anyway. I have experienced them failing unexpectedly in the middle of summer. Replacement is simple and the stems are inexpensive.
You should have a good quality valve stem remover/installer before attempting stem removal. There're sometimes in there pretty tight.
- Remove the dust cap from the connection port.
- Position the valve stem remover/installer tool with the end that grabs the stem and begin twisting and screwing out the stem. If the stem appears stuck, grab the tool with a pair of pliers and them apply twisting torque.
- Apply a little compressor oil on the new stem O-ring and screw the stem in with the remover/installer tool. Do not over-torque the stem.
VIII. Connecting the AC Service Hoses for Evacuation (Pulling Vacuum)
- Attach the blue service hose to the blue-dialed low-pressure port service coupler.
- Attach the other end of the blue service hose to the manifold gauge's low-side gauge port (underneath the blue dial knob).
- Connect the low-pressure port service coupler to the car's low-pressure port. Connecting is easier if you turn the blue dial valve counterclockwise. Once the coupler is connected, turn the blue dial on the coupler clockwise to apply pressure to the valve and open a connection.
- Attach the yellow hose to the center port of the manifold gauge.
- Attach the other end of the yellow hose to the vacuum pump.
- Pre-vacuum setup check: The blue low-pressure adapter knob is open when turned clockwise, and the blue knob valve on the manifold gauge is open when turned counterclockwise.
IX. Starting the Evacuation
Turn the vacuum pump on. The needle on the low pressure gauge will swing counterclockwise into the minus zone (which is the green area on the gauge I am using). Let the evacuation go on for approximately 30 minutes to remove all moisture.
Note: If after a few minutes the vacuum reading is minus 25 or less, there is, more than likely, an open area in the AC system. A leak-free system should be in the minus 28 zone. To know for certain, close off the low pressure side blue dial valve by turning the dial counterclockwise and turn off the vacuum pump. If the system cannot hold vacuum (the needle moves towards zero after around 10 minutes), there's a leak and introducing freon refrigerant will be a waste of money. A mild leak may indicate either the high or low pressure valve stem springs are too weak to hold a high amount of vacuum and is not indicative of a leak in the system. In that case, a mild amount of leakage is acceptable.
Complete the evacuation by:
- Closing the valve on the low-pressure coupler.
- Closing the valve on the low-pressure manifold gauge.
- Turning off the vacuum pump.
- Disconnecting the low-pressure coupler from the low-pressure port.
Recommendation: After removing the low-pressure coupler, immediately connect the Freon recharge dispenser fitting. Sometimes the valve stem will allow air to come into the system because the valve spring is too weak.
X. Recharging the A/C System with Freon Refrigerant
Typical sedans and SUVs will need approximately 25+ oz of Freon refrigerant. Some vehicles will have a label fixed inside the engine compartment indicating the amount of Freon needed for the system. Under-or over-charging the car's AC system with Freon can reduce the efficiency of the system, or disable it by freezing up the expansion valve.
- Spin on a new can of Freon onto the Freon recharge dispenser.
- Press the trigger on the dispenser to pressurize the dispenser line.
- Connect the dispenser's quick connect fitting onto the low pressure port.
- Begin dispensing Freon into the system. Rotate the can up and down every few seconds. When the dispenser's pressure needle is around 60 psi, the can should be close to empty and the car may be started with the AC on, the windows open and the HVAC on recirculation.
- 5If there's enough Freon in the system, the AC compressor's clutch should engage. Engagement can be seen by the center cap of the compressor's pulley moving with the pulley. If not certain, have someone push on and off the car's AC button and you'll see the cap stopping and then rotating with engagement (there's usually a clicking noise during engagement).
- Set the bottom of the dispenser's temperature dial (if the dispenser has one) to the approximate outside temperature. The gauge's needle should be between the red lines. If there's too little Freon, the gauge needle will oscillate on some vehicles. As the proper amount of refrigerant is being reached, the oscillation will stop. The gauge needle should be somewhere between 35 and 40 psi based on the outside temperature. The hotter the ambient temperature, the higher the psi.
- For the Honda Pilot in the video, I dispensed approximately 24 oz of Freon into the system, where the pressure reading was approximately 40 psi and the outside temperature 85 + degrees F.
- Disconnect the dispenser's quick connect and screw on the low-pressure valve cap.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
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