Install Guide: Zero/Sports Cool Thermo Thermostat

**edoperformance** · 09-17-2007, 03:49 PM

Hello again from EDO Performance!

Today we have for you an installation guide for the Zero/Sports Cool Thermo Thermostat. It is being installed on a 2002 WRX, but the procedure will be the same for any other 2002+ Imprezas as well as most other Subarus.

The Zero/Sports Cool Thermo Thermostat Fits any 1992 and up Subaru has a valve opening setting of 160*f (71*c) which is 12*f (7*c) cooler than the stock thermostat setting. This allows the cooled water to circulate back from the radiator into the engine faster and keep the overall temperature cooler.
The need for a more efficient cooling system is even more vital with today’s turbocharged Subarus, such as the WRX and the STi. The factory cooling system has to work even harder now that it is being used to cool both the engine’s oil and the turbocharger. This added strain on the cooling system can result in increased coolant temps leading to many negative side effects, one of the most unwanted being detonation that causes the vehicle’s ECU to adjust timing, resulting in a loss of power. A hotter running motor also generally has a shorter lifespan than a cooler motor.
We gave this thermostat a test run in a 2002 WRX on a hot day and recorded full-throttle temperatures at an average of 24*f cooler with the Zero/Sports thermostat (196*f before, 172*f after). This thermostat isn’t just for modified vehicles; it can benefit even a stock car. The design of this thermostat allows it to open completely in the event of a thermostat failure, the stock thermostat will fail closed and cause the vehicle to overheat. The Zero/Sports Cool Thermo Thermostat is such a simple upgrade with substantial benefits; you can’t afford not to use it.

1. First thing you will have to do is get the car up. Jack stands, ramps, or a lift, whatever’s handy. You will need to let the car cool for a good 30-60 minutes before starting to work on it.

2. While the car is cooling off, you can pull the plastic skidplate out from underneath. It’s held in by a few 12mm bolts and plastic clips, the clips can be removed by prying the center up with a screwdriver.

3. Once the car is cool, you can start draining the coolant. There are 2 ways to do this. The first is the method listed in the Subaru service manual seen here:

This method works just fine, except that the drain plug you open spills coolant all over the subframe which makes it hard to catch in a bucket, making a big mess everywhere.

4. The second method is a bit easier and cleaner. At the bottom of the radiator on the drivers side you will see where the lower radiator hose connects to the thermostat housing. To drain the coolant, remove both radiator caps (only one on some models), place the widest bucket you can find under the thermostat housing, then after removing the hose clamp, remove the hose as slowly as you can. Coolant will start to pour out pretty fast so you will want to get the end of the hose right into the bucket. Coolant inside the motor will be draining slowly out of the thermostat housing too.

5. Once all the coolant has drained out, you can remove the thermostat housing. It is held in by two 12mm bolts. One can bee seen easily in the picture, but the other is hiding behind the inlet for the housing.

6. Once the housing cover is off, you will be able to see the old thermostat. It might tale a little work to pry it out, and there might also be some more coolant hiding behind it waiting to pour out so keep that bucket handy.

7. Insert the new Zero/Sports Thermostat oriented the same way as the stock one fit inside the housing. Replace the cover/bolts and torque to 10 ft/lbs. Reattach the lower radiator hose to thermostat housing and retighten hose clamp.

8. Follow the instructions In the service manual page seen earlier to refill the system with coolant.

9. Enjoy your cooler running Subaru!

If you would like to request an install guide for any of the other products we carry please fee free to contact us!

-Kevin
AIM: EDO Kevin

joSTIzel · 09-22-2007, 09:38 PM

excellent writeup! would'nt have known the t-stat is located underneath... THANKS!!

JD_STI · 09-22-2007, 10:00 PM

nice guide. So will this cause longer warm-up times?

**edoperformance** · 09-24-2007, 10:04 PM

no it wouldn't cause longer warm up time. The thermostat will open earlier after you car warm up

09-17-2007, 03:49 PM	#1
edoperformance Authorized Vendor Car: Zero/Sports TA STi Posts: 550 Join Date: Oct 2005 Trader Rating: (16)	Install Guide: Zero/Sports Cool Thermo Thermostat Hello again from EDO Performance! Today we have for you an installation guide for the Zero/Sports Cool Thermo Thermostat. It is being installed on a 2002 WRX, but the procedure will be the same for any other 2002+ Imprezas as well as most other Subarus. The Zero/Sports Cool Thermo Thermostat Fits any 1992 and up Subaru has a valve opening setting of 160f (71c) which is 12f (7c) cooler than the stock thermostat setting. This allows the cooled water to circulate back from the radiator into the engine faster and keep the overall temperature cooler. The need for a more efficient cooling system is even more vital with today’s turbocharged Subarus, such as the WRX and the STi. The factory cooling system has to work even harder now that it is being used to cool both the engine’s oil and the turbocharger. This added strain on the cooling system can result in increased coolant temps leading to many negative side effects, one of the most unwanted being detonation that causes the vehicle’s ECU to adjust timing, resulting in a loss of power. A hotter running motor also generally has a shorter lifespan than a cooler motor. We gave this thermostat a test run in a 2002 WRX on a hot day and recorded full-throttle temperatures at an average of 24f cooler with the Zero/Sports thermostat (196f before, 172f after). This thermostat isn’t just for modified vehicles; it can benefit even a stock car. The design of this thermostat allows it to open completely in the event of a thermostat failure, the stock thermostat will fail closed and cause the vehicle to overheat. The Zero/Sports Cool Thermo Thermostat is such a simple upgrade with substantial benefits; you can’t afford not to use it. 1. First thing you will have to do is get the car up. Jack stands, ramps, or a lift, whatever’s handy. You will need to let the car cool for a good 30-60 minutes before starting to work on it. 2. While the car is cooling off, you can pull the plastic skidplate out from underneath. It’s held in by a few 12mm bolts and plastic clips, the clips can be removed by prying the center up with a screwdriver. 3. Once the car is cool, you can start draining the coolant. There are 2 ways to do this. The first is the method listed in the Subaru service manual seen here: This method works just fine, except that the drain plug you open spills coolant all over the subframe which makes it hard to catch in a bucket, making a big mess everywhere. 4. The second method is a bit easier and cleaner. At the bottom of the radiator on the drivers side you will see where the lower radiator hose connects to the thermostat housing. To drain the coolant, remove both radiator caps (only one on some models), place the widest bucket you can find under the thermostat housing, then after removing the hose clamp, remove the hose as slowly as you can. Coolant will start to pour out pretty fast so you will want to get the end of the hose right into the bucket. Coolant inside the motor will be draining slowly out of the thermostat housing too. 5. Once all the coolant has drained out, you can remove the thermostat housing. It is held in by two 12mm bolts. One can bee seen easily in the picture, but the other is hiding behind the inlet for the housing. 6. Once the housing cover is off, you will be able to see the old thermostat. It might tale a little work to pry it out, and there might also be some more coolant hiding behind it waiting to pour out so keep that bucket handy. 7. Insert the new Zero/Sports Thermostat oriented the same way as the stock one fit inside the housing. Replace the cover/bolts and torque to 10 ft/lbs. Reattach the lower radiator hose to thermostat housing and retighten hose clamp. 8. Follow the instructions In the service manual page seen earlier to refill the system with coolant. 9. Enjoy your cooler running Subaru! If you would like to request an install guide for any of the other products we carry please fee free to contact us! -Kevin AIM: EDO Kevin This ad is not endorsed by this member. Please register or login to hide this ad. Last edited by edoperformance : 10-05-2007 at 08:47 AM.*

09-22-2007, 09:38 PM	#2
joSTIzel Amateur STI Driver Car: 04 Subaru WRX STi Fav Mod: FMIC Location: LI. New York Posts: 21 Join Date: Jul 2007 Trader Rating: (0)	Re: Install Guide: Zero/Sports Cool Thermo Thermostat excellent writeup! would'nt have known the t-stat is located underneath... THANKS!!

09-22-2007, 10:00 PM	#3
JD_STI Spec C Club Car: 07 STI Fav Mod: Zzyzx Coilovers Location: SoCal Posts: 1,177 Join Date: Jul 2007 Trader Rating: (0)	Re: Install Guide: Zero/Sports Cool Thermo Thermostat nice guide. So will this cause longer warm-up times?

09-24-2007, 10:04 PM	#4
edoperformance Authorized Vendor Car: Zero/Sports TA STi Posts: 550 Join Date: Oct 2005 Trader Rating: (16)	Re: Install Guide: Zero/Sports Cool Thermo Thermostat no it wouldn't cause longer warm up time. The thermostat will open earlier after you car warm up This ad is not endorsed by this member. Please register or login to hide this ad.