My standard disclaimer: I am a n00b. My 86 Z28 is my first Camaro, as well as the first car where I am doing my own work.

I have a 305 with 4 bbl carb, rebuilt, with about 65000 miles on it. I am seeing the temp range of the motor all over the map and need some advice.

Driving at speed yields a temp of about 160 on the gauge. Prolonged stop and go or sitting in rush hour will make the temp creep up to 220 (midway on the gage) and up to 240 at times (evily close to the red zone). Am I seeing symptoms of a bad thermostat? With a good thermostat, what should I see as normal operating temp? The midpoint of the gauge (220)? I also don't seem to hear the fan kick in... it should be pretty noticeable on such a large motor, right?

Thanks for the guidance as I improve my "Car Guy" mojo.

 

A new stat is certainly cheap enough to give it a shot, but expect no miracles. It is more often a clogged up radiator, bad water pump, inadequate or non-functional fan system when temps start creeping up in stop-n-go traffic.

Also, don't overlook the state of tune of your motor. Ignition timing that is retarded or advanced from where it should be, running lean, etc. can all contributor to throwing more heat at the cooling system than it is capable of getting rid of.

Last one, and it's almost a knee-jerk reaction around here to overheating problems.... do you have the plastic "chin spoiler" under your radiator support? Is it properly attached and in good condition? These little pieces of plastic are critical to proper cooling in a 3rd gen.

 

I do have the air dam on and in good shape.

 

Don't worry too much about it, stock the fans don't come on until 230* and even then they don't always come on. Stop and go traffic hits these cars hard because the bulk of the cooling air is directed up and through the radiator by the airdam. Since you're running at 160* driving then I'd guess your tstat is working fine.

You have options, you can look into an aftermarket fan switch that will activate the fans at a lower temp, or you could go over to thirdgen.org and read ******* fan articals and learn how to hotwire the fan or setup manual switches. You can also hotwire the fan to run constantly whenever the key is on (my personal current choice) but it might cause the fan motor to die more frequently.

Don't worry too much about the radiator, if its still the original, one of the side tanks will likely crack in the next couple years.

 

The radiator is newish as well (less than 2 years), current to the engine rebuild.

So do I worry or not?? LOL If the fan doesn't kick in until 230, what should I expect the "normal" operating temp to be? What are other owners' experiences? Should I only worry about too much heat if the temp gauage red lines?

(I'm really appreciating all the tips and info I am getting.)

 

Oh, you have the electric fan(s)? Turning them on at a lower temp is fairly easy. You can buy aftermarket fan switches that kick them on at lower temps than stock. It's bascially replacing the factory fan switch that is screwed into the pass. side cylinder head between #6 & #8 spark plugs. This is for single fan systems.

On dual fan systems (TPI engines) one fan is controlled by the ECM and the other is controlled by...... oh, I forget, I think it's when you kick on the A/C or something like that. Go read a tech article over on thirdgen.org about "ultimate fan control" or some such title. It describes exactly how your fan(s) work, what turns them on and off, etc.