497FIREHAWK

My Car Is A 1994 Firrehawk #497 Of 500
Recently In The Past Few Months Ive Been Having Trouble With Overheating Issues. Ive Flushed The Radiator, Changed The Water Pump Twive, Changed The Temp. Sensor Twice, Had The Heads Resurfaced As Well As A Valvejob, Changed The Gaskets Eliminated The Heater As Well As The A/c. And I Cant Go Five Mile Cause My Temp Gauge Goes Up To Between 3/4 And The Red Area? I Also Had A Mechanic Check The Radiator Pressure And It Didnt Go Over "0" Lbs. I Have Also Bleed The System. What Could It Be?????????

davidarel

get a new radiator cap.

00JoeZ28

I'm having the same problem too. Can anyone let some light in on this situation. What could be going wrong? Everything on my '97 SS checks out fine but it does the same thing as 497firehawk's car. What happened to these two fine automobiles?

oneslowz28

How did you bleed they system? You have to fill it up cap it off let it run till it gets to operating temp then open the thermostats bleed screw and you will hear air escape then you open the radiator cap and fill it up until you do not hear anymore air coming from the bleed screw. Close it and run it some more and then open the bleed screw back up and repeat the process until no more air escapes. Remember to put a towel or rag under the bleed screw because you do not want any coolant getting on the opti. If you have the heater system still in then you also need to bleed that with its bleed screw at the same time your bleeding the thermostats bleed screw.

If you didn't follow this procedure than your system is not bled properly and that is the cause of your over heating.

also put your thermostat in a pot of boiling water with a cooking thermometer and see if its opening at 180 degrees. If it does then its fine. I would replace that thermostat as it slows down the water flow in the system allowing the water to "absorb" as much heat as possible. I've had people come to me asking for a new radiator because there car was overheating and the only cause of there car overheating was that they removed the thermostat and it was letting the water flow too fast to provide any decent heat exchange.

Also your cat could be stopped up and needs removal or replacing. Crank it up at night and let it run for a few min and open your hood and if you see your exhaust manifolds glowing red. If they are glowing red then your cat is stopped up.


*edit* I noticed that you said that there cooling system is not pressurizing. This leads me to believe that you do have air trapped in your system and that is what is causing your overheating issues. The system should pressurize. Try bleeding it the proper way and reinstalling the thermostat and see if that fixes it. If it doesn't check for clogged cats with the method I mentioned above. If there fine then I may lean to the Clogged radiator side.

How Often did you change the coolant?

Laymaster

a few years ago I had an overheating issue. Turns out the radiator got "clogged" per say...nothing a flush would do, but only like 1/3rd of the radiator was cooling the engine. New radiator and all was good.

bitchin94

I'ld just buy a 160 degree thermostat and you would be done that is what i did to my stock LT 1 and it never hits half way on the temp gauge also turning on your A/C will kick on your fans this should cool it right down.

oneslowz28

with the system not pressureizing the thermostat isnt the problem. he either has air in the system or has a clogged radiator could be causing the overheating as well but im leaning to the air in the system

CamaroFan71

My car did the same thing. Took off the top fan shroud and the radiator was caked with dirt and leaves. Blew all that out and now it runs just fine again.

00JoeZ28

Once mine starts to act up though, it starts making bubbling and gurrgling sounds. And the hoses start to bounce around. seriously. And yes I have bleed the system.

Dave '97 Z28 M6

Fans working?

xpndbl3

fans not working or radiator cap defective? possible air bubbles in the system due to the flush could cause this as well.

oneslowz28

you have either a blown head gasket or a cracked head.

Heatmaker

You did all that work, but never bothered to try a new radiator?

Injuneer

Please post only once, in the appropriate forum. I'll merge this with your identical thread in "LT1/LT4 Engine Tech".

00JoeZ28

The motor is completely rebuilt and my heads checked out fine man. And I know it's not a head gasket either. Maybe I didn't fully pressurize my system, going to try today. Just got home. This motor has just been started but only twice on a fresh rebuild. I haven't even been able to fully heat cycle the engine, let alone even start the break-in period.