Maybe someone can help me. 92 rs camaro 305tbi everything is stock except for the headers and exhaust.
New correct rotation water pump
New aluminum radiator and cap
Custom fan shroud with dual 12 inch fans with switch
New 160 thermostat
New o2 sensor
New fuel filter
Fuel pressure is good at 11.5 psi
No check engine light
All air dam are intact nothing is missing or crack
No ac and condenser is out of car
50/50 water and antifreeze mix
Lower bottom radiator has a spring
Standard tranny
Check plug and it's running correctly
Check the head gasket and it's good.
Here's my problem, if I leave the fan on all the time it runs cool around 180-190 in traffic or highway, but as soon as I turn off the fan when I'm on the highway the temperature climb up to 240-250, the only way I can get the temperature to go back down is by turning on the fans and leaving it on. Is this normal for the third generation camaro, I had other cars and never had this problem. And no the water doesn't boiled or leak. Help me

 

Sure sounds like an air flow problem. A car driving at 50 MPH should have twice the air flow that that a stock fan would give.

 

"Custom fan shroud with dual 12 inch fans with switch".
What kind of a fan shroud is it? If it's one of those nifty flat aluminum ones (not tapered), then that may be your problem. I know a couple of guys who had a flat shroud with overheating problems. After suggesting they remove the shroud, the overheating issue was solved. Reason is, incoming air hits the flat wall that is the shroud, and flow through the radiator is stifled. And this was with cars that have an open grill like mine. Your car gets air from down low via the air dam, and it needs all it can get.

 

I made the shroud myself and yes it made out of aluminum and it's not flat it has a one inch depth with some air flaps on it, it was still running warm even with the original fan on it, I though this shroud will fix it but it didn't. I beginning to think its how these camaro where made, you have to leave the fan on.

 

I think so too now. Long as I leave the fan running it won't go pass 200

 

The point I am trying to make is that no fan should be able to flow more air then the car should have flowing above 45 MPH. If you have ever run a dyno you know that even the best cooling systems need help with the car sitting still. We had a 220v 48" fan we put in from of cars to try to get air flow equal to about 60 MPH.

If the problem is air flow while you are moving over 45 MPH the fan is a helping the symptom but not fixing the problem. You need to figure out why you don't have a mass of air running through your radiator.

 

I don't know I think all third generation just dont flow enough air as it is....but I will keep trying different things and see what will work...

 

I have similar setup you are taking about, as far as aluminum rad and dual elec fans etc etc, I have none of the shrouds behind the front bumper, and no shroud around the fans, I have never gone above 180 degrees neither in traffic or on the highway, and my fans are never on going down the highway