Step 2: Radiator Removal and Thermostat Swap

1. Alright, go ahead and carefully work the radiator (with fans attached) out of the car. You will take the assembly to the right a little and up. It’s not too hard. There is a 1″ black rubber line clipped to the left side of the radiator at the top. Unclip that and manhandle it a bit as you’re removing the radiator as needed. Congratulations.
   
2. Transfer the hard line (that goes to the coolant overflow tank) to the new radiator.
3. Transfer the fans to the new radiator.





4. Transfer the bottom main hose over to the new radiator or install your new one if you bought a silicone radiator hose set. Clamp it of course.




5. Now for the thermostat. If you’re not installing one, skip this step and the next 2. The blue lines in the picture to the right are pointing at bolts which you cannot see. If my memory is right, they are 10mm, and once broken free can be removed easily with your fingers. Those bolts hold the thermostat “housing” in place. The thermostat housing is nothing more than that pipe you see in the picture with the coolant draining from it. At any rate, keep your catch can in place underneath that area and remove the bolts and the housing. More coolant will pour out.
6. Insertion and removal of the thermostat is difficult without either a mirror or a digital camera with an LCD viewfinder, but I suppose it can be done. Grab the thermostat with your fingers and pull it out of the block while taking a close look at its orientation as you get it removed. It is only wedged in there with a gasket around its diameter. Set it aside.
7. Install your new thermostat into the block so that the little beady pin thing (see picture) is at 12 o’clock and the thermostat is facing the right way. It will most likely fit tightly, but make sure it is seated in there well. Reinstall the thermostat housing with the 2 bolts and torque them to 5 ft/lbs or go ahead and crank down on them and strip the threads in your shortblock if you like adventure.

Step 3: Install the Radiator

1. Working from the right a little, just as you removed it, get the radiator in place. It should have 2 pegs on the bottom which slide into the lower radiator mounts (rubber). If you need to, get under the front of the car to confirm this. I did.
2. Attach the lower radiator hose to the thermostat housing tube and clamp it
3. Plug in the fans
4. Install the 2 upper radiator mount brackets to secure the radiator in position
5. Attach the 2 left-most (small) hoses that go to the coolant reservoir
6. Install the upper radiator hose



7. Install the plastic coolant overflow tank to the right of the radiator and connect its hose to the hardline mounted on the radiator (the other end should already be connected from the step above)
8. Attach the thick hard rubber hose on the left top of the radiator to the clip. See picture to right.
9. If it’s not already, remove the coolant reservoir cap.
10. Pour a small amount of coolant into the reservoir (a pint or so)
11. Shake the Subaru Coolant System Conditioner (small blue bottle) very well and pour it into your bottle of coolant. Shake it up a little to mix it in.
12. You have two options at this point. Option 1: Fill the system completely via the coolant reservoir (this is what I did). Option 2: Unhook the top radiator hose on the block end, raise it up, and fill a gallon or so that way before reconnecting the hose and proceeding with filling via the coolant reservoir. For the sake of this article, I am proceeding with describing Option 1.
13. At your discretion, begin pouring coolant and/or distilled water into your coolant reservoir. Stop after a half gallon or so and check under the car for leaks of any kind. Fix the leaks if there are any. I had none.
14. Continue to add another half gallon or so (whatever mixture you choose)
15. Make sure the car is in neutral and start the car (be careful if the car is on jack stands, etc). Let it idle and proceed to the next step



16. Continue pouring coolant and/or distilled water into the coolant reservoir at a slow rate. You will see bubbles rise to the surface as the air is expelled from the system. Keep an eye on the coolant level in the reservoir though while the car is idling. It only takes a few minutes before the system will start trying to overflow from heat while your cap is off. If it happens, turn off the car, get the cap on as fast as possible, and clean up your mess while waiting 45 minutes before proceeding.
17. At some point, you will have the cooling system stabilized and air-free with the reservoir cap in place. Your car should be able to idle and drive just fine without overheating. When you take the car for a test run around the block, bring some coolant and/or distilled water with you in case you need it. If you do need it, remember not to pop the cap on the reservoir while the system is pressurized and hot.
18. After a run around the block a few times, take the car out for a few miles and back, let it cool down fully, remove the reservoir cap, start the car (let it idle), and add any coolant/water necessary to top off the system. Check for leaks a second time.
19. Most problems (overheating) after an install are a direct cause of air still in the system. When cool, remove the reservoir cap, idle the car, watch for bubbles, add cool/water as necessary…. etc.

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