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Pelican Technical Article:

Expansion Valve Replacement

Steve Vernon

Time:

4 hours4 hrs

Tab:

$30 to $200

Talent:

***

Tools:

Philips, Flathead screwdriver, 5mm, 3mm Allen, 10mm socket

Applicable Models:

993 Non-Varioram (1995-95)
993 Varioram (1996-98)

Parts Required:

Expansion valve

Hot Tip:

Remove and save refrigerant for re-use.

Performance Gain:

Working A/C.

Complementary Modification:

Check the A/C lines and O-rings for possible leaks.

The expansion valve is an important part of the A/C system. After the hot refrigerant gas is condensed into liquid by the condenser, it gets sent to the expansion valve. The expansion valve is used to bleed off the pressure from the hot refrigerant liquid. When the pressure drops, the result is that the refrigerant cools to the point where it can now enter the evaporator and complete the process of getting cold air in your car on a hot day. If you have trouble keeping the A/C temperature cold, and there is plenty of refrigerant in the system, it may be possible that the expansion valve is damaged or faulty. Also the O-rings between the lines, evaporator and expansion valve can go bad and become a source for coolant leaks.

You are going to be opening the A/C lines. It is very important that you have the refrigerant removed and stored or disposed of by a professional before you open the lines. Opening up charged A/C systems and venting the refrigerant to the atmosphere is illegal and dangerous, please make sure to have your refrigerant professionally removed and re-installed if good or properly disposed of!

Keep your A/C blowing nice and cold by always replacing the line's O-rings when working on your car's A/C lines.

Things are packed pretty tight in modern Porsches and that includes the 993. One of the important questions you will ask yourself when you start working on your Porsche is: how the heck do they expect me to get at that part without removing this part? The truth of the matter is that a lot of times you do need to move other parts, systems or components out of the way to change something and then re-install them. Lots of first time DIY'ers get frustrated working in really tight spaces or end up damaging something they are not working on just to "save the time" of having to remove other components. If you are going to work on your 993 get in the habit of moving things out of the way and giving yourself all the room you can to work; in the end you will end up saving time and money.

The firewall is one of the parts that needs to be moved out of the way for several jobs including changing your expansion valve. This article will show you how to safely remove the firewall along with changing your expansion valve, but we do recommend getting a friend to help lift it out the first time you do it, not because it is heavy but because you do not want to scratch the paint.

Over the years your car may have been serviced by multiple people including previous owners and this can lead to parts replaced with different size fasteners and hardware. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.

You are going to be working with the main electrical control board which houses the main fuse and relay panel.
Figure 1

You are going to be working with the main electrical control board which houses the main fuse and relay panel. Before you begin you must disconnect the ground strap from the post on the battery and place it where it cannot accidentally come in contact with the post while working (red arrow).

The firewall is located behind the gas tank and in front of the HVAC suite case which contains the expansion valve.
Figure 2

The firewall is located behind the gas tank and in front of the HVAC "suite case" which contains the expansion valve. It has a rubber weather sealing gasket along the top of it (red arrow).

Begin by removing the weather seal by simply pulling it up and off (red arrow).
Figure 3

Begin by removing the weather seal by simply pulling it up and off (red arrow).

Use a short Philips head screwdriver and remove the two screws (red arrows) holding the shroud in place and remove the shroud.
Figure 4

Use a short Philips head screwdriver and remove the two screws (red arrows) holding the shroud in place and remove the shroud.

Remove the electrical connection for the blower motor regulator by squeezing in the clips and pulling it up (yellow arrows) then gently pry the wiring harness connector from the back of the regulator (red arrow).
Figure 5

Remove the electrical connection for the blower motor regulator by squeezing in the clips and pulling it up (yellow arrows) then gently pry the wiring harness connector from the back of the regulator (red arrow). The regulator is attached to the heat sink plate and this is mounted to the firewall and will come out with the firewall.

With the weather stripping off the firewall (red arrow) use a Philips head screwdriver and remove the three screws and (yellow arrow) and remove the corner plate between the control panel housing and fender.
Figure 6

With the weather stripping off the firewall (red arrow) use a Philips head screwdriver and remove the three screws and (yellow arrow) and remove the corner plate between the control panel housing and fender.

Unscrew the plastic retaining knob in the upper corner (red arrow).
Figure 7

Unscrew the plastic retaining knob in the upper corner (red arrow).

Using a 5mm Allen remove the single bolt in the front corner.
Figure 8

Using a 5mm Allen remove the single bolt in the front corner.

Do not lose the plastic shim that goes between the panel and housing.
Figure 9

Do not lose the plastic shim that goes between the panel and housing.

You can now lift the panel, fuses, and relays and wiring harness up and out from the housing.
Figure 10

You can now lift the panel, fuses, and relays and wiring harness up and out from the housing. Place a shop towel down between the panel and fender and tie the panel out of the way.

You're now looking at the fuse panel housing which is attached to the fire wall (red arrow) and the fuel expansion tank (yellow arrow); you do not need to remove the expansion tank to remove the firewall.
Figure 11

You're now looking at the fuse panel housing which is attached to the fire wall (red arrow) and the fuel expansion tank (yellow arrow); you do not need to remove the expansion tank to remove the firewall.

Use a 10mm socket or wrench and remove the bolt holding the bottom of the fuse panel housing to the chassis (red arrow).
Figure 12

Use a 10mm socket or wrench and remove the bolt holding the bottom of the fuse panel housing to the chassis (red arrow).

Next use a Philips head screwdriver and remove the screws holding the housing to the inside of the fender.
Figure 13

Next use a Philips head screwdriver and remove the screws holding the housing to the inside of the fender.

Move to the left side of the firewall and remove the top two Philips head screws and loosen the lower one.
Figure 14

Move to the left side of the firewall and remove the top two Philips head screws and loosen the lower one.

It is a tight fit and having a Philips head ratchet really helps.
Figure 15

It is a tight fit and having a Philips head ratchet really helps.

With the top two screws removed and the lower screw loosened you can remove the plate that allows you to remove the firewall without completely removing the lower screw.
Figure 16

With the top two screws removed and the lower screw loosened you can remove the plate that allows you to remove the firewall without completely removing the lower screw.

If this is the first time you have done this it is a really good idea to get a friend to help you lift it out as even though the piece is not heavy you do not want to scratch anything.
Figure 17

If this is the first time you have done this it is a really good idea to get a friend to help you lift it out as even though the piece is not heavy you do not want to scratch anything. It lifts straight up and out (red arrow).

Now you have easy access to the A/C lines where they join the expansion valve (red arrow); you do not need to disconnect the sensor on the line to perform this work (yellow arrow).
Figure 18

Now you have easy access to the A/C lines where they join the expansion valve (red arrow); you do not need to disconnect the sensor on the line to perform this work (yellow arrow). Again, you are going to be opening the A/C lines. It is very important that you have the refrigerant removed and stored or disposed of by a professional before you open the lines. Opening up charged A/C systems and venting the refrigerant to the atmosphere is illegal and dangerous, please make sure to have your refrigerant professionally removed and re-installed if good or properly disposed of!

Separate the lines from the expansion valve by removing the 10mm bolt and pull the lines straight back.
Figure 19

Separate the lines from the expansion valve by removing the 10mm bolt and pull the lines straight back. There are two O-rings on the lines to expansion valve that must be replaced.

Use a 3mm Allen and remove the tow bolts that hold the expansion valve in place.
Figure 20

Use a 3mm Allen and remove the tow bolts that hold the expansion valve in place.

You might need to pull and wiggle the expansion valve off of the two pipes from the evaporator.
Figure 21

You might need to pull and wiggle the expansion valve off of the two pipes from the evaporator.

There are also two O-rings on the evaporator pipes to expansion valve that need to be replaced.
Figure 22

There are also two O-rings on the evaporator pipes to expansion valve that need to be replaced. Installation is the reverse of removal. Once the system is resealed you can have to old refrigerant reinstalled or you can recharge the system. I recommend using a professional shop for recharging the system as they will pressure test it as well.

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Page last updated: Fri 1/20/2017 03:14:52 AM