i have an 89 iroc and i got it back on the road about a month ago. it was warming up on idle so i decided to start changing parts to make sure it was running good. over the past month i have replaced and added the following things.

-Month old Failsafe thermo 180
-New autozone Radiator
-New autozone waterpump
-Radiator flush (flushed twice with chemical and about 7 times with regular water, had lots of rusty water)
-Water Wetter
-Full strength Antifreeze mixed with distilled water to about a 60/40 ratio
-Sucked the air out of the system for any air pockets

<---- that's me at this point.

i drove it on the freeway and at first it was well under the mid 220 line. then it slowly but surely started creeping up. it got to the third line right before the red zone. i put it in neutral and got off the free way and let it cruise till i hit the stop sign and waited for about a minute. it started going back down, i stepped on it a bit since i had just ran seafoam in the car and it ran the temp down, then i cruised in 5th gear and it started going back up. Someone please help me, any ideas or suggestions? I understand these cars run hot, but not this hot. whats average temp? between 180-220? I've been reading that air damns help tremendously so im going to purchase one. any help would be appreciated

These cars are bottom breathers. You must have the air dam to direct the air into the radiator in order for them to cool. Mine broke years ago while on the highway and my car started to overheat within minutes. I have since put a slightly bigger one on that I modified to fit and haven't had a problem since. Also I would recommend checking your timing. Im assuming your fans do come on. might want to look into having them come on at a lower temp with a chip or a different temp sender

I know the higher engine temp was to help improve emissions but these cars are on the edge of overheating constantly. If this is tbi there is a list on the forum with napa part numbers for cylinder temp switches. I find that on at 200f and off at 185f keeps the engine around 2-210 all the time .

sounds like your missing the air dam like said above

LOOKING FOR THAT THREAD WITH THE NAPA PARTS FOR MY TBI???

I would say invest in a gauge that reads accurately. I chased an overheating condition on my car for months. Ended up going in circles. How could all these new parts still have the car overheat. My factory temp gauge would do the same thing, slowly climb on me. Well, I ended up buying an inexpensive electric temp gauge and just tapped into the factory sending unit. The car never overheats. I ended up putting a more reasonable fan switch back in because the one I had installed from Jet, had the fans coming on too low of a temp, since I thought the engine was running hotter than it was. Long story short, those factory clusters are starting to get old, and do weird things with age. If your radiator cap isn't blowing off steam, and the car isn't running differently, I'd bet you the gauge is faulty. My car runs at about 170' on the freeway on a warm afternoon with a 180' tstat and 4 core radiator, dual spal fans. Never gets above 200'F around town.