i have a 01 sunfire with 115K

ive had an over heating issue for a while now
first time i noticed it i added more coolant and it seemed the prob went away
a few months later it overheated where the temp went all the way up to high
pulled over for a few min and let it cool down drove 2-3 min to home and let it sit
noticed the whole container was nearly emptie so i added more coolant
drove fine for a few weeks
the normal operationg temps were right in the middle
a few days ago i noticed it started over heatting again...well kind of the temp is about 3-4 lines above the mioddle
im pretty sure i have no leaks
where do i start?
could it be the fan?
air bubble in the line?

I'd do a compression check first, you may have lost the head gasket. Then check the water pump is actually moving fluid...

Actually.. you could just have an air bubble in there that the system needs purging... check that too.

is there anyother signs of a bad head gasket? or malfunctioning water pump?

i know on my old car i had the same problem and it was air in the line, there is a valve that can be opened to let any air out.. do sunfires have this as well, if not how would i check for air bubbles?
tyhanks

i just noticed that my car heats up in a matter of 3 min after its turned on
i also noticed that the fan doesnt turn on

waht is the diagnostics of this problem
is a bad fan a common problem?
how much is a new unit?

not necessarily.

if there is no coolant, or air bubble, your temp readings will be off, and can cause fan malfunction.

If your car is waroming up that fast, you either
a) have no coolant
b) coolant is not circulating, either water pump is brokded, or T-stat is stuck.
c) cooland has no passage to go....ie dexcool mud.

I would pressure test the coolant system to check for leaks. maybe put some uv dye in it first, so you can see it easier.
Then, once the car warms up, see what the temp is on the upper rad hose.....then the lower. are they the same, or close?? is one piping hot, and the other cool to the touch??