DIY : GT500 Thermostat Change

Couldn't find one of these when I looking for a how-to on changing the thermostat, so I thought I'd take a few minutes to snap some pictures while changing it. It was super easy, took maybe 20 minutes start to finish, and is a great way to help your motor run cooler.

Tools needed:

Siphon pump (bought at Home Depot for $12)
Bucket
Ratchet
8mm socket

Step 1:

Remove cap to coolant tank. Use siphon pump to empty coolant out into a container.




Step 2:

Loosen 8mm bolts holding thermostat housing together



The bottom bolt is in an awkward spot... careful when removing it, it would be very easy to drop into the abyss

Step 3:

Pull thermostat housing apart (A few drops of coolant will come out), and remove the old thermostat




Step 4:

Put rubber o-ring around new thermostat, and replace.




Step 5:

Replace thermostat housing and bolts. Tighten bolts down - they are 8mm and threading into aluminum, I'm not sure what the torque spec is on these but DO NOT be Hercules when tightening these down



Step 6:

Place container with coolant in it above the level of the coolant tank, and use siphon pump to transfer it back over



Step 7:

Start the car, make sure there are no leaks, and change your fan settings!

 

It can only be done via a tuner - I believe you can do it from the Xcal3 without needing a laptop or anything, not sure about other handhelds. The car will still run cooler on the highway, but for it to really take advantage of the thermostat, you'll need to set the fan to come on at a lower temperature so that it will run cooler when sitting in traffic and at low speed, too.

 

Reische recommends setting it to high 188°/low 182°.