I just started the firbird for the first time in 17 years. I had the motor completely rebuilt, I even replaced all bolts. I put the motor together but,I had everything machined, resized, replaced new all down to the new four core radiator, seven blade fan and thermostat. My problem is "OVER HEATING". It ran for 15 min. and go to 230 deg. I didnt have the shroud on. The clutch fan came on at 220 deg. Tomorrow im going to run water over the radiator as its running and see what happens. Ill also time it. Im just venting.....Joe

Congrats Joe on finally firing her up! I bet it is the best sound you have heard in a long,long time! Don't worry, i'm sure you will have the overheat problem licked soon enough. Did you fully bleed the cooling system? An air pocket will make it run hot. Congrats and goodluck!

David.

Dave,
How do you fully bleed the cooling system? I just filled it up and watched to see the thermostat open and topped it off.
Oh and yes, God the motor sounded tough. Nothing sounds better than a PONTIAC!!!!!!! It sure got the nieghbors attention.... Joe

joe, take off the radiator cap, start her up and keep squeezing the top radiator hose till you do not see anymore air bubbles in the radiator.

A simple trick to get the air out of the system is to drill two or three 3/16" holes in the thermostat plate. This lets a small amount of water circulate continuously, and eliminates virtually all the air from the system.

Q

A simple way to prevent an air pocket in the block is to have the themostat out before you fill the radiator. Start putting in antifreeze & water mixture in radiator & watch the level of fluid reach the intake crossover & fill until it leaves enough to install the themostat & water neck. Then fill to the cold fluid level in radiator & you are done! This will prevent an air pocket in cooling system.

Steve

Congrats Joe!!
This must be a pretty darn exciting time for you. Don't worry about the temp issues, there are plenty of us here to tell you all sorts of things to do about that.

I but a new ignition modual in the mallory unilite dis. Needles to say $94.00. It only lasted about 2 hours and it went bad. Ill see what the parts store says tomorrow. I tried to put the new fan shroud on but its for a camaro.... not a firebird. I pulled the thermastat out and started it up in the driveway still gets past 225. I took a house fan and placed it in front of the radiator. It did help but i still had to spray water on the radiator to cool it down. Its not the water pump because the water was moving fast through the radiator. Ill get the right fan shroud and see what happens. It was in the high 90degs. outside when I did start it. I might even go with a helper elect. fan.. Thanks Joe

If the engine is rebuilt it will run a little hotter because of friction. I was just "burping" my cooling system yesterday. I was amazed at how much air was stuck in the system. You really need to be running a shroud to help direct airflow through the radiator and not around it. On my A/C car there is one seal missing at the bottom lower left of the radiator support (front of car). All the hot air from the engine bay blows out through this opening because it's the path of least resistance. The same will happen if you don't run a shroud. All the air will flow around the radiator instead of through it. I need to fix this because the hot air will only get recirculated through the radiator again. Congratulations on firing up the new engine.

G.J.
1968 350 Coupe

Congats joe, on starting up you engine. I am in the process of building mine back up. I will be paying close attention to how yours is coming along. The last time i built my 400, I also had heating problems.
Wade