Hi everyone!:
After a nearly 2.5 year hiatus in my v8 install, I resurrected the install project. Many factors have prevented me from completing the install during this time(full time student, advancements at work. Etc.), however I have resumed the project with new vigor. My current problem is that I have an overheating issue. I MUST SAY that this problem is in the very early stages and that I'm pretty sure that there may still be some air in the system.

Technical stuff: Car has never been driven yet, 327 SBC, conventional water pump with Archie drive, new radiator from 1987 corvette installed . On 2 occasions I have started this car and after 10- 15 minutes it gets hot (240*), BUT the heart of my post is during both of these attempts the radiator is STONE cold. I have put approx 4.5 gallons of coolant in the system. Does this sound like an air lock?? any help or insight will be greatly appreciated. !!!

Hooter

It is most likely an air lock. With the waterpump installed upside down, the coolant inlet to the pump must "jump over a hill". If there is air in this location, the coolant will not make the jump and will not circulate any coolant.

My SBC pump has the rear raised about 6" for a variety of other reasons, but it provides a level path for the coolant to enter the waterpump.

Engine HOT........ Radiator COLD

At this point, no matter what engine is in the car (or what car you have the engine in), you have a lack of coolant flow.

Fill & bleed the cooling system & make sure the 'Stat is not stuck closed.

Next time you test it the 2 heater hoses up front where they connect to the heater core, to see if one or both are getting warm.

Archie

Did you fill the system with the car level to the ground, or did you fill the system with the car's nose or tail raised?

I had an issue with my car when i did a swap. first it turned out that the coolant tubes under the car were mistaken for a jack point... the second issue was that i filled my system on level ground.

after that, i just drained it. and did the following:

1) I got the nose of the car about 3 ft higher than the rear with some ramps (the higher the better, i assumed)

2) I got a buddy at the rear to burp the T-Stat, while i poured coolant in with the hose leading to the T-Stat clamped off. This made the coolant travel into the engine first, then up to the T-Stat. When it filled the engine, we replaced the T-stat and housing.

3) He unclamped the upper coolant hose, and I started filling the system again from the front of the car at the rad.

4) when it gurgled out, he reclamped it, attached it to the T-Stat, and started it up. burped the T-Stat and the rad at the front for a some time while still on the incline. then took it down to level to make sure it wasnt overheating.


Good luck, and check if the tstat is working properly.

As long as you take all the caps off, you don't have to tilt the car at all. With one fill point at the rear and the cap off the radiator, just pour water in at the rear until it is about to dribble out the front. Install the cap on the radiator and continue to fill from the rear.

The high point at the waterpump that Fieroguru discussed could also cause issues. Just leave it open until water comes up to the edge and is about to dribble out, then make the connection, snug the hose clamp and continue to fill.

You'll have to make allowances for the thermostat as well.

Guru,Arch, JCUIOT,Will;
After going over this system again I was able to extract about a quart of air from the system, after all of this, the next run cycle included circulation to the radiator and no overheat.

quote Originally posted by fieroguru: It is most likely an air lock. With the waterpump installed upside down, the coolant inlet to the pump must "jump over a hill". If there is air in this location, the coolant will not make the jump and will not circulate any coolant.

Guru, I looked closly at this and I noticed what you mean. do you thing drilling,tapping and adding a bleeder to th new "top" of the WP impeller housing would help this?

thanks again to all, I'm really getting excited about this project again!!!!

hooter

[This message has been edited by hooter (edited 01-28-2009).]

The main air pocket of concern would be in the actual inlet hose. You could put a small section of pipe in there and add a bleeder screw to it.