Pelican Parts
Porsche Parts Catalog Accessories Catalog Porsche How To Articles Porsche Tech Forums
Call Pelican Parts at 888-280-7799
View Recent Cars  |Shopping Cart Cart | Project List | Order Status | Help
 >  >
Oil Cooler Resistor Replacement
 
Bookmark and Share

Pelican Technical Article:

Oil Cooler Resistor Replacement

Steve Vernon

Time:

2 hours2 hrs

Tab:

$70

Talent:

***

Tools:

15mm, 10mm, 5.5mm socket, Philips screwdriver, trim removal tool, multi-meter

Applicable Models:

Porsche 993 Carrera (1995-98)
Porsche 993 Carrera 4 (1995-98)
Porsche 993 Carrera 4S (1996-98)
Porsche 993 Carrera S (1998)
Porsche 993 Targa (1996-98)
Porsche 993 Turbo (1996-97)

Parts Required:

Resistor

Hot Tip:

Glue the metal plate and bolt to the resistor

Performance Gain:

Proper oil cooling

Complementary Modification:

Change your oil and filter

Proper oil temperature is critical for the air cooled engine in the 993. As Porsche started to develop larger and more powerful engines, they had to add additional cooling to the oil system to keep up with the demands from the engine. Part of this system is an auxiliary oil cooler in the front right fender of the vehicle. This cooler also uses a fan to help pull air through it when you are sitting in traffic or the temperature just gets too high. There is a resistor in the front right corner along with this cooler and this resistor will help modulate the fan. If your fan only comes on at high or isn't coming on at all, the resistor has probably failed. This is a very common problem in the 993s and if you own the car long enough you are going to have to replace the resistor. The resistor is in a very tight working space and after you have replaced it once or twice you may be able to just reach in and change it out, but if this is your first time, take your time and move some components out of the way. It will only take a few extra minutes and will save you time in the long run. I removed the fan for photographic purposes but you do not need to remove it to change the resistor.

You will need to remove the forward right wheel well liner and lower tray to access the resistor and while some people say you can remove the liner and replace the resistor with the wheels on I recommend you safely lift and support the front of the vehicle; please see our article on safely lifting and supporting your Porsche 993 for additional instructions.

First thing you want to do is test the resistor to make sure it's bad.
Figure 1

First thing you want to do is test the resistor to make sure it's bad. You will need to access the fuse and relay panel. Open the hood and pull back the carpet. The fuse and relay panel are in the rear by the A-pillar on the right side.

Locate and remove the oil cooler fan relay and then using your fused jumper wire jump terminal 30 with terminal 87 (red arrow, use the relay for reference).
Figure 2

Locate and remove the oil cooler fan relay and then using your fused jumper wire jump terminal 30 with terminal 87 (red arrow, use the relay for reference). If the fan goes on high, you have power to the fan and it works.

Next use your fused jumper wire and jump terminal 30 and 87C.
Figure 3

Next use your fused jumper wire and jump terminal 30 and 87C. You should get the fan working on low speed. If nothing happens then you have a bad resistor and will need to start getting access to it by removing the right front forward wheel well liner.

To remove the forward liner, begin by removing the Philip head screws including the three that join the liners on the top (red arrows).
Figure 4

To remove the forward liner, begin by removing the Philip head screws including the three that join the liners on the top (red arrows).

Working under the vehicle remove the two 10mm plastic nuts holding the liner to the forward protection tray (red arrows).
Figure 5

Working under the vehicle remove the two 10mm plastic nuts holding the liner to the forward protection tray (red arrows).

There are two pieces of weather stripping on the forward liner (red arrows).
Figure 6

There are two pieces of weather stripping on the forward liner (red arrows). Once the liner is removed this is a good time to clean these out and get some rubber protectant on them.

You need to remove the liner from the wheel arch as this makes it easier to get off the air duct on the inner fender well.
Figure 7

You need to remove the liner from the wheel arch as this makes it easier to get off the air duct on the inner fender well.

While professional mechanics will remove the fan without removing the under tray, I do not recommend it.
Figure 8

While professional mechanics will remove the fan without removing the under tray, I do not recommend it. It is a tight space to work in to begin with and any extra room I have to work in I appreciate. Remove the lower tray by unscrewing the three Philips head screws (red arrows).

Slide the tray forward using a trim removal tool to help release the plastic tabs holding it in place (red arrows).
Figure 9

Slide the tray forward using a trim removal tool to help release the plastic tabs holding it in place (red arrows).

Remove the drain tube from the fan and place it up out of the way.
Figure 10

Remove the drain tube from the fan and place it up out of the way.

Unplug the electrical connection for the fan by pulling it straight up (red arrow).
Figure 11

Unplug the electrical connection for the fan by pulling it straight up (red arrow).

Disconnect the wiring for the cooler temperature sensor by squeezing down on the wire and pulling them apart (red arrow).
Figure 12

Disconnect the wiring for the cooler temperature sensor by squeezing down on the wire and pulling them apart (red arrow). Note: this step is not critical but just gives you more room to work by getting some of the wires out of the way. I have removed the fan to get better pictures but you do NOT need to remove it to perform this job, if you would like to at this point you just need to remove the four 10mm nuts holding it in place.

Use a 5.
Figure 13

Use a 5.5mm socket and remove the three bolts holding the deflection plate to the cooler (red arrow) and remove the plate.

There is an upper plate behind the cooler that the resistor and resistor wiring connection are mounted to (red arrow).
Figure 14

There is an upper plate behind the cooler that the resistor and resistor wiring connection are mounted to (red arrow). If you have done this before and have small hands you might be able to reach in with a 10mm socket and remove the nut holding the resistor in place. Look at the rest of the instructions to see if you want to try this but I recommend if you are doing this for the first time to follow the steps laid out here.

Use a 15mm socket and remove the three nuts for the oil cooler tray (red arrows) and the 10mm nut on the upper bracket (yellow arrow).
Figure 15

Use a 15mm socket and remove the three nuts for the oil cooler tray (red arrows) and the 10mm nut on the upper bracket (yellow arrow).

At the front of the cooler remove the two 10mm nuts (red arrows) holding the front bracket in place and remove the bracket.
Figure 16

At the front of the cooler remove the two 10mm nuts (red arrows) holding the front bracket in place and remove the bracket.

Remove the cooler and bracket from the chassis.
Figure 17

Remove the cooler and bracket from the chassis. If you look up towards the front bumper you can see the 10mm nut the holds the resistor in place on the top of the shelf (red arrow). You will also need to reach in and separate the wiring connection from its holder (yellow arrow).

Once the nut and connection are removed you can thread the resistor (red arrow) out so you can separate the wiring (yellow arrow).
Figure 18

Once the nut and connection are removed you can thread the resistor (red arrow) out so you can separate the wiring (yellow arrow).

Installation is the reverse of removal, but a trick is to super glue the metal plate that goes between the resistor and shelf along with the bolt that goes into the resistor in place first, it makes installation a lot easier.
Figure 19

Installation is the reverse of removal, but a trick is to super glue the metal plate that goes between the resistor and shelf along with the bolt that goes into the resistor in place first, it makes installation a lot easier.

Bookmark and Share

QUICK LINKS
About Us
Careers
Pelican Parts, Inc.
1600 240th Street
Harbor City, CA 90710
Order Online or Call:
888-280-7799
CONNECT WITH US
NEWSLETTER
Sign Up for Pelican Pit Stop News & Special Offers
Page last updated: Sat 4/29/2017 03:17:30 AM