800660 – Subaru VA Coolant Overflow Tank

WRX 2015-2021
WRX STi 2015-2021

Congratulations on your purchase of the COBB Tuning VA WRX Coolant Overflow! The following instructions will assist you through the installation process. Please read them BEFORE beginning the install to familiarize yourself with the steps and tools needed. If you feel you cannot properly perform this installation, we HIGHLY recommend you take the vehicle to a qualified and experienced automotive technician.

Parts List

Coolant Overflow
Coolant Overflow Cap
Coolant overflow upper bracket
Washer fluid tank adapter
Washer fluid fill hose
Washer fluid fill cap
Trim stud
m6x10mm flanged hex bolt
m6x16mm flanged hex bolt
(2) m6x10mm hex drive flat head screw
Flanged Hex Nut
6mm flat washer
6mm lock washer
7/8 - 5/8 id Rubber Grommet
(2) 6mm silicone vacuum hose
m6 stud with 10mm hex

Tools Needed

Sockets

3/8"

Hand Tools

Wrenches

Disassembly

Park your car in a flat level area and allow it to cool down.
Squeeze the radiator hoses to make sure the coolant system is fully depressurized.
As long as things are cooled down and the radiator hoses easily squeeze and don't feel as though there's pressure, remove the coolant cap.
pull the hose gently out of the coolant overflow tank, most of the fluid should drain back into the tank. If not lift the end of the hose upward to get it to drain back into the radiator.
On the side of the overflow tank that is towards the headlight (not the radiator) you'll notice the end of the tank is underneath a small tab. press this in to release the coolant tank and rotate it counter clockwise to free it from the fan shroud. you can then lift up and remove it from the car.
Set it somewhere safe, but leave it upright. You'll use the coolant later on.
Locate the windshield washer fluid cap. Using a phillips screwdriver slightly turn the trim clip holding it in place, it should lift up slightly.
With it slightly separated fit a trim tool or flat head screwdriver into the clip to pull the inside out slightly. This should make it so you can now remove the lower half of the trim clip.
Grab the fill tube and gently lift upward. It should release from the lower half of the tank.

Washer Fluid Fill Tube.

Remove the o-ring off of the stock fill tube and put it around the COBB Fill tube adapter.
Gently push this into the washer fill port.
Put the provided silicon tube onto the new fill port with the logo at the top.
You can now put the small delrin fill cap into the tube.

Coolant Overflow Install

Push the rubber grommet into the billet top bracket.
Grab the shorter of the two provided bolts. Push the bolt upwards through the hole the trim clip for the washer fill tube was originally in.
Screw the billet trim stud onto the bolt and tighten the two hand-tight with a 10mm socket on the bolt, and a 17mm on the stud.
STI FMIC Install Only
Install the provided stud with a lock washer and flat washer on the short end into the threaded hole on the side of the overflow.
Using the provided bolt, install the overflow tank to the unoccupied bolt hole on the frame rail behind the headlight. Leave it loose for the time being.
Push the rubber grommet in the top bracket over the installed stud with the tapered side of the holes facing up.
Using an M4 Allen wrench, screw the tapered top bolts into the top bracket.
STI FMIC Install Only
The stud coming off of the side of the overflow tank should provide a point to attach to the brace on the side of the cold pipe, installing through the center aluminum spacer and tightening with the provided m6 serrated nut.
Once you've gotten the top bolts tightened down you can go ahead and tighten the bottom bolt with an M10 socket and extension.
Push the fill tube for the washer fluid into the pracket sticking out from the overflow tank to provide support.
Install the provided length of hose over the factory radiator overflow nipple and run it down into the overflow tank making sure its just missing the bottom (you may need to trim 4"-5" off of the hose for it to fit perfectly).
You can add the coolant from the old overflow tank into the new one at this time. If you're doing a complete refill of the system you'll typically want to keep the overflow around 1/3 of the way full.
Install the Delrin overflow cap.
You're all done! go out and enjoy!