I have an 85 Z-28 with a ZZ4 carbed,3.73 gears and 5spd. Nothing else done to it so it has 10:1 like it came from the crate. I have a Griffin 2 row aluminum radiator w/ (1) 16" electric fan (cfm's unknown). The motor has an aluminum high volume water pump and a 160 degree thermostat.

Now here's the scenario/problem. I drove it today in the 90+ degree weather in stop and go traffic. It was fine and basically ran @ 180 degrees while driving then the traffic started to move slower. The temp slowly crept up to 230-235. I finally got frustrated and took a side road and opened it up. The car immediately cooled back down to 200-210. It finally went back to about 260 when I got home. I felt the radiator hose and felt the antifreeze boiling (plus you could hear it).

This motor never ran hot when it was in my S-10 with a smaller radiator w/ dual electric fans and a cast iron water pump? What gives?

I am leaning towards changing the fan and putting on a dual electric fan setup with more RPMs or a Ford Taurus fan ( I heard these work great).

Has anybody else had this problem? How did you solve the problem? What size electric fan (part #, brand and price) did you use.?

Has anybody used a Ford Taurus fan before? If so how did it work, cooling wise.

Here are pics of my set up(Just your basic set up):




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One more thing .I don't know if this makes a difference but the fan is not mounted flush to the radiator. It is mounted to the top part of a factory shroud and mounts to a bracket down at to bottom and bolts to the radiator support. There is approx. 3/4" - 1" space between the fan and the radiator.

 

Just a quick thought here. Try reversing the fan wires and see if the fan pulls more air. Get some tissue paper, toilet paper or other light paper and put it by the front of the radiator when the fan is on and see how the fan pulls the paper. When I installed after-market fans in my `88 Iroc I had the same problem, switched the wires and problem solved. If that is not the problem you may want to check out Spal dual fans on a site called Jaycorptech.com. I`m going to try dual fans and shroud from an LS1 and see how they work.