I am new to this BB, and have cooling problems like so many others. I just bought an 89 IROC Z-28 a couple weeks ago--350 TPI--700 R4, with a lot of performance mods already done. Supposedly--balanced, blueprinted (bottom end stock)--heads port, polish, CC, ports matched, mild cam, Edelbrock throttle body w/24# injecters, TPIS runners, MSD ignition, custom chip--Ed Wright Automotive in Tulsa (anybody know if he actually programs them, or if this is just where the previous owner got it from?), hooker headers, 3" (?) system to rear bumper, air pump and plumbing left OFF, 2000 Stahl TC, tranny redone-shifts hard and converted to manual shift only--with B + M Slapstick shifter, aluminum driveshaft, 3.73 posi, subframe ties, strut tower cross brace, 17" Budnik wheels and Comp T/A's, alarm, stereo, ETC.

I have pretty much read through all of the FAQ's, articles and threads, and understand all of it (even though it's been a few years since I've been "hot rodding" I'm just an old fat guy--51, that refuses to get old!) both in theory and pratical application.

The cooling problem is that if A/C is turned on during the day, (live in HOT AND HUMID Houston, Texas) the temp will start climbing up to 250 or more (if I would let it!). If I turn it off , even in slow city driving, it will go back down to about 210/220 by the cheap after market gauge that previous owner installed, (instead of fixing in-dash gauge). I checked that both fans were running (replaced both of them just for good measure--one was questionable) replaced the 180 stat with the same, (I think it might have been sticking when I first got it--car had sat for a while), I have checked to see that I have good water flow with Rad cap off. Air dam underneath is in postion and in good shape.

With all of this in mind, I temporally wired both cooling fans in a closed loop, so both fans are running 100% of the time when key is on. Still does the same thing! On freeway it runs 220/230 with A/C on, with it off around 200/210. I guess by simple trouble-shooting techniques, this should tell me that either the fans are not pulling enough air, or the 2 row radiator (good flow and fins clean and straight) is just not up to the job because of the performance mods? I even removed the rubber strip on back of hood, to try and get some air flow through engine compartment and reduce ambient temp. All it did was make my windshield fog up easier with A/C on!

Suggestions Please!
Go to better fan/fans (if so, can anyone suggest what brand and type or configuration?), or is it time to go to alum. rad (again, can anyone suggest what brand or type would be the hot tip?)? Is there a 3 row non-alum. rad available for this --straight bolt -in?

If A/C system (although it seems to work good even in day time Houston weather) is in need of freon, will that make the A/C coolant hotter than normal that is going through the cooler on front of rad and effect the total cooling system enough to cause this?


Also, quick question about external tranny cooler. There is one on front lower right (passenger) side of rad. Is it better to run lines through rad AND external cooler, or is it OK to run it JUST through the external cooler? I suspect the previous owner set it up through the external cooler only, as it is now, thinking it was contributing to the total overheating problem.

I'm sure y'all (that's one of those Texas expressions) will see a lot more posts from me in the future, since there is a lot of stuff that I am not happy with the way they were done or other stuff that I want to do in the future. I'll try not to make a pest of myself, and ask too many stupid questions, but I figure if I ask the people that have already gone through it , it will save me a lot of time and energy--something I am running low on!!!

Wish this BB had a "spell chucker" on it!

 

Since Willie seems to be "The Man" (read your articles--impressive) was wondering if U had any thoughts on this one!