I've got a 98 Z28. Ive always had a problem with engine getting hot ever since I got the cat bout 6 years ago. So I installed a manual fan switch that has helped. But now my engine temp climbs fast as soon as I start driving and it stays right around 210 - 230. Even with fans running or on interstate it doesn't cool down. Don't know if it's the water pump going out? Thermostat? Never have changed thermostat or flushed system. So hope that's it. A lot cheaper on the wallet. Any ideas?

 

Normal as thermostat, if OE design, is 195°F to start opening and 205°F when fully open.
Higher temps for reducing exhaust emissions.

Welcome to the Club, John.

 

yep flush it and change the thermostat. test your temp gauge sensor. its by the number one spark plug. have you checked the radiator to make sure its full up.

 

look at 12, 17 and 20 here 4th Gen LT1 F-Body Tech Aids

 

The place I add coolant shows full so I've never looked inside radiator. When I turn off motor when it's over half way on temp gauge you can hear coolant boiling and it sometimes comes out where I add coolant. Im guessing that is the overflow. I'm a real novice at this. Usually just take somewhere but want to do it myself.

 

when the engine is cool or cold take the radiator cap off and have a look inside. it should be full to the rim.

 

your going to need to get some of the coolant out of the overflow tank too. needs to be at the right level or close.

 

Another thing to consider is you timing advance curve. Sounds like a lot of mods to your engine and if the advance curve is not set up correctly you engine will over heat. You may have to reprogram your chip to try a less aggressive timing advance to move the heat out the exhaust port. In the old days we did this with weights and springs in the distributor but now its all an ECU function unless you happen to have a mechanical distributor.

 

sounds like the water pump or thermostat boiling water meens its not cooling right? is it leaking ,I would not drive it until you get it fixed with that aluminum block cant take very much heat could couse other issues fast with over heating ? does your water light come on ever then go off ,its a wavey red light indicating water issues

 

if its low on coolant you will need to bleed the air out of the system. look here https://camaroforums.com/forum/lt1-l...-system-66742/ may want to do it anyways to make sure. air in the system will cause issues just like what you are seeing. also could be you need a new radiator cap. a failing cap can alow air to get back into the radiator. a hole in the hose or pipe on the overflow feed will also let air into the radiator.