How the heck do you add coolant? Do I really need to take off the tire and remove the wheel well?

Or, can I remove the top of the thermostat housing and add coolant that way?

 

You can just remove the tstat cap and add or if you have time, just pour into the tank at the fire wall and let it drain down. It takes a while but then you will have the tank up to the proper level also.

 

If you try to remove the cap on the tower, you are liable to break it, unless it has been replaced by an aluminum unit.

As larueb says, use the screw cap on the header tank at the rear of the engine compartment, and do it when the engine is cold.

 

If you are doing a drain and refill, you basically "must" fill it through the tower cap at the front of the engine. And, yes, if the cap is old, it will probably crack. Go buy a new one. If you fill through the surge tank only, the engine will likely try to overheat suddenly due to trapped air. If you must fill through the surge tank after a drain and refill, a good idea is to run the engine with the heater on, and speed the engine up to circulate the air out of the system. You can be fairly certain you are good when the floor heat is good and warm! I would still watch it carefully the first few miles driven. And, check it again after it cools off to see if it needs additional topping up. If you are just "topping up", adding through the surge tank is the proper method.

 

Yes, I have an aluminum thermostat housing. My kitty was very, very well taken care of prior to my adopting her.

THANKS GUYS!!

 

I removed the cap and kitty drank about 24 ounces of filtered water.

 

Yours may be a kitty, but mine is a motor car.

 

Not sure exactly what the coolant tank setup is on a 99 but 28oz is alot of lost fluid. The low coolant sensor usually triggers when down 4-6 it's very sensitive.
If you didn't see a warning light indicating this you might want to check the sensor and it's wiring connection, also that water has to go somewhere you may want to pressure check the system as well.