How to Replace Corvair Bellow Thermostats

 

Every Corvair has two accordion-like bellows thermostats on each side of the engine attached on the lower shroud. If you have no clue where, simply stand back from the rear of the car and look under. You will see two rectangular doors on each side. When the engine is cold, they are closed, when hot, one or both will be open. If the thermostat is bad, the door will simply stay open. This is not a bad thing per se in the summer, but in the winter, it will take longer for the engine to warm up. You can do this without raising the car, it takes around 45 min. to take it off, clean and replace it and reinstall. This method uses no special tools as others require. It also keeps the settings that came with the car avoiding the problem of knowing how to set them.

1. Remove the door post by carefully lifting up the tab, which keeps it attached. With pliers,  pull it out and do not lose the washer on the other end.

 

2. Remove the lower shroud by removing the 5-6 screws holding it onto the block. The shroud may need to budged but it should drop down easily. Since the door is still attached, you will slide it out backwards until free.

3. To remove the thermostat, you need to unscrew the door connecting rod that connects to it

4. Now, remove the thermostat from its bracket. To do so, compress and squeeze it and twist and turn, wiggle, until it is free. This takes a little time, but eventually it will come out. Use a wrench to unscrew the bolt from the bracket.

5. Replace the old bellows with a new one or good used one. Simply insert it into the bracket and attach with the bolt and tighten. Reattach the door and rod by screwing the door rod to the new bellows. This is a bit awkward because of the door still attached, but not an issue. It will look like the photo in Step 2.

6. Reinstall the whole unit by carefully reinserting the door first until the door sits correctly as the other one does. The washer for the rod you took out in Step 1, must be attached before you reinsert it.  The difficult part is once the whole unit correctly positioned, insert the door rod through the hole and into the other hole so it freely moves. You really cannot see it, so it is by feel or location. When done, make sure the door freely opens and closes. Reattach the shroud bolts into their former positions.

You are done!