Written by: Methanoxide
This is a guide so if any damage is resulted from following this, it's not my fault!
This guide is for changing a thermostat on a manual transmission Paseo. California cars and automatics are different but you should still be able to use this guide. You will also have an EGR system that might be in your way.
Reasons for changing a thermostat:
- Your car is overheating. Your thermostat could be stuck closed not allowing coolant to get to the radiator to cool down.
- Your car runs too cold. Your thermostat is stuck open constantly keeping your engine 'cold'.
- You don't have heat in the winter. Either the thermostat is stuck open or the one you have in there is opening up too soon. Get a 190F for the winter then.
Before you start you need a list of things:
- Bucket to catch coolant
- Star and flat screwdriver
- 10mm & 12mm socket w/ ratchet
- New thermostat and rubber gasket
- 320 grit wet-or-dry sandpaper
- Clean shop rag
- Floor jack
Jack up the front of your car. Remove the passenger side splash guard, and set the bucket up to catch your coolant.
Refer to the next image to locate the radiator drain plug. Make sure your bucket is centered to catch the coolant. This is not necessary, but it drains the coolant faster.
Undo the drain plug slowly until the coolant starts to come out. You don't need to fully remove the drain plug. Once it starts to seep out you can remove the radiator cap to make it flow faster.
Start removing the intake piping in order to access the thermostat housing located below your distributor.
After all the bolts and screws are removed take the top portion of the air box off and remove the cold air duct. Next you need to remove the lower portion of the air box.
Now your ready to get the thermostat out! First remove the rad hose and disconnect the water temperature sensor.
** CAREFUL HERE BECAUSE SOME COOLANT WILL STILL DRAIN OUT FROM THE BLOCK/HEAD. HAVE YOUR BUCKET READY TO CATCH SOME MORE. **
Get your 10mm socket and undo the two nuts holding the thermostat housing on.
Once its all disconnected slowly remove the housing revealing the thermostat.
Before you install the new thermostat you should give all the surfaces that the rubber gasket touches a good cleaning. Use the 320 grit wet-or-dry sand paper to remove and gunk. I don't recomend a course grit sand paper because the housing is aluminum and scratches easily.
Remove your new thermostat and gasket from its packaging and put the rubber gasket on the thermostat.
Carefully put the new thermostat back into the housing and put it back onto the engine. Make sure the hole in the thermostat flange is facing up (if it has a hole).
Now reverse your steps to put everything back together.
Once everything is back together, keep your car up on the jack and fill up the radiator and overflow bottle with some new engine coolant. Turn your heat on inside your car on full blast with full heat and start it up.
Check for any coolant leaks.
If there are no leaks, let your car idle until it reaches temperature. Keep your heat on full blast. What your doing is trying to get all the air bubbles out of the system and by keeping the radiator higher than your heater core and idle air controller it will force the air bubbles out. You can occasionally rev the engine to help it.