We just got a 94 Z28 and its an awesome and clean car. The only issue is that the car gets pretty hot and we can't figure it out and don't know much about these engines. There's no signs on head problems. The secondary fan doesn't want to turn on unless relay is jumped even with new ones. And primary only turns on low. Thermostat is new and good. Going insane trying to figure it out. Gave up daily driver for it. Oh and part store gave a relay for it that don't go in fuse box but can't figure out where it goes and its got 3 relays and bled system. It boils out when AC is on.

 

pull the top radiator support off and look in front of the radiator. Mine had a plastic shopping bag covering more than half the surface.

 

Well now we've changed the ect sensor with no change there's nothing in the fan or radiator and it still gets hot even when fans are forced on.

 

What temp are you calling "pretty hot"? You need to get both fans working like they should be. If there is not any blockage of air, there might be some in the cooling system or the water pump is not pumping well (impeller might be slipping on it's shaft). All hoses hooked up and going to the right places? Proper and operating thermostat?

 

what does the filler neck on the radiator look like when you take off the rad cap (when cool) is it "gunky looking"? gets hot when? 20mph and faster? city traffic? dexcool likes a sealed up system. is your air dam in place?

 

The neck is clean and it'll get hot at any speed even just idling. And the air dam where the radiator is is removed.

 

as shoebox asks-what is "pretty hot"? what is the gauge indicating?

 

It gets to the red then we instantly shut her down and let her cool completely. Is there a way to check the waterpump? We got the fans working right now but it got to 3/4 on the gauge and was holding for a bit even with AC running then I hit a bump in the road and the oil pressure dropped low and the temp got up to the red in a couple of blocks. Did notice the oil gauge runs barely over the red on the bottom at a warm idle and not even the first line when at regular speed and not sure if that's normal

 

have you installed the correct "2 stage t-stat" for an lt1 cooling system? other than that-i would wager your radiator is plugged.

 

If I am reading it right, the air dam removed, you arent talking about the black air deflector on the bottom of the nose? If thats what you are referring too, you most surely need to replace it! I ran my car with it off on 1 trip on the highway, and I ended up having to pull a fuse to throw a code and get my fans to stay on to keep it cool enough to get home! Might want to check it out!

 

The thermostat is just the 185° one that the parts store said was the right one and the air piece I was talking about is the black piece that's set back underneath it some.

 

Yes, you NEED to replace that! Without that there is no airflow reaching the ANGLED radiator. 100% sure you will find your solution by replacing the air deflector, which sits about...2 feet back under the nose, i believe its a row of 8mm bolts, pretty simple, and makes a big difference

 

Sounds wrong. The stock thermostat in an LT1 is 180*F. It has to look like this:

Courtesy of Shoebox

http://shbox.com/1/tstat.jpg

 

how is your coolant? is it diluted somewhere around 50/50? it isnt just straight coolant? did you bleed the system of trapped air after the stat install?

 

So the thermostat that we were given is like the one that shoebox says and shows as wrong it looks just like an ordinary thermostat and yeah we bled the whole system when we installed it. We're going to try to find a thermostat that looks like the one Shoebox shows for it and see if it solves our problem today.