when the A/C is on the 2 big fans run.. you may have a problem with the
little fan further towards the front of the car.. it is supposed to turn on
around 230 degrees...

troy

A/C turns on both fans.  The most likely culprit is debris between the A/C
condenser and the radiator.  I have no idea how the stuff gets into such a
small space, but the radiator on my '91 was about 25% blinded with an
assortment of what looked like straw, fur (?), and other material.  I
flushed the cooling system with a heavy duty cleanser, cleaned out the air
passages in the condenser and radiator, and it cools fine now, even in 100
degree summer weather.

Does the '93 have the LT1?
It's a urban rumor that the reverse flow
cooling system is more prone to T-Stat failures
from the design.... I've gone through a couple
through the years on my '94. Then went to PowerStats
and haven't had a problem since.

You have several problems.  I have a 92 and had the same problem last
summer.  First, the radiator is not up to the task of cooling the car.
Go to MidAmerica.com and get an all aluminum radiator.  Second, change
all the clamps to worm type.  Those clamp on that cam from the factory
let air enter the system when the car sits.  Changing the clamps is good
for five degrees.  Get an inspection mirror and look at the back of the
waterpump and I can almost bet it is leaking if you have not replaced it
recently.  Change your radiator cap as it is long overdue and go with
the highest pressure you can get from the dealer.  Yes, go with a low
temperature thermostat 180 degree.  If you try the 160 route it will not
work and the car will heat up.  The water circulates too fast.  Flush
the catch tank and system.  Do, not backflush the system unless you are
in the mood to change the heater core.  The heater core is really thin
and any excessive pressure in the system will make it spring a leak.  I
know as I have replaced several heater cores due to people backflushing.
 Go with a 50/50 mix of water and demineralized water.  Distilled or
deionized are fine.  Go with normal anti-freeze and not the five year
stuff as it does not cool as well.  Replace your fan relays and if your
fan still does not come on get a power programmer for your car to turn
the fans on sooner.  A 93 has an embedded chip so you have to get the
programmer as you cannot remove the EPROM.