I also have a 96 z28. Both of my fans come on when I turn on the ac. If one or both of your fans do not turn on, this could be a few reasons. One could be the fan motor is toast, wiring problem, or possibly but not for sure, the computer. If you are interested, read my postings...

Fan Problems

If your fans are not keeping your engine / cooling system cool, then it will boil over. I normally notice the heat rise on the car when its warm out or have been driving a while and come to a stop.


Also a really good write up here from shoebox Shoebox A/C & Fans
Oxy

 

so upon checking the fans, i found the fans on pass. turns on if i unplug sensor on water pump. the driver sid eis on slp switch, alway on. should i wire both together? I'm going to take it to shop on wednesday...

 

I don't think it would be a good idea to wire both together. There is a reason why they are separate. It might also might sent a engine code. Check your relays and the terminals where your relays plug into. I hooked power directly to each fan to see if the motors actually worked. Then the relays and then the fuse box terminals.
Your Camaro is also a 96 so just look at the write up on the relays and terminals and compare.

I'm just wondering if your over heading and loosing coolant while driving down the road.

 

if i disconnect the connecter to the sensor on the water pump. the second fan comes on...

i just notice something the car is a 94 I sold the my 96

 

Oh my bad I thought it said 96. So both fans work then Im thinking your sensor on your water pump is shot. (coolant temp sensor) The pig tail should be supplying 5 volts with your car turned on (engine off). You can check your sensor a few different ways.

1. test with sensor in pump with car cold, then with car hot
2. take sensor out after draining a good portion of the coolant and test in a pot of water on your stove. You can watch the resistance values change.

(test in ohms for resistance)

Completely cold (50-80 degrees F, 5,700 to 2,200 ohms)
Warm running temp (170-200 degrees F, 200-300 ohms)

3. Or just replace (cost in Canadian here is $20.00 for a sensor at NAPA)


Oxy

 

ok guys just got my car back from a local shop. they said they did pressure test, leak down test, block test, and compression test. all test came back good. they chrage me 20 dollars after working on it all day. they said they got a code once during test (code 15). all in all they said they could not find anything wrong with car that would make the coolant low. i will check it again after i cools down. what do you guys think i should do now?

 

I'll say again:

 

i did checkthe hose and shaft for leaks. did not have leak. but do you think it could be the seal around shaft?

 

It's highly possible not to see a coolant leak, but as the coolant cools down outside air is sucked into the system. Just get both, they are not much $ at all.

 

cool i will get them tomorrow..

 

so guys i have replaced the overflow hose and shaft. still same problem. i did notice that the car holds preesure in radiator until released(two days). so when i open top of radiator, water will flow out like its hot. what could cause that? then when driving it fills the overflow more now. the coolant will not over flow nor will car over heat if i leave it running at idle(left for hour), so the problem only happens after driving. what could this be?