67 327/350hp Cooling System Question

[bobmanx]

Hi all, still learning........ Is there a "correct" method to filling a C2 small block cooling system after all radiator hoses, heater hoses and thermostat have been replaced? Does it fill from the expansion tank or ? There has to be a method to get all the air out and antifreeze in, other than just pouring it in the expansion tank and waiting for it to displace the air. Whats the secret to getting it "full" or a proceedure so there's no damage to the motor by trapped air? The factory manual says very little, other than "replace/fill with approved coolant".

Thanks for all help and suggestions, Bob

 

[JohnZ]

Bob, I've always used this method, never had any trapped air problems. Remove the thermostat housing from the intake manifold (leave the upper hose connected to it, just push it out of the way for now), and remove the thermostat. Fill the system through the opening in the intake until the level rises near the top of the opening, install the thermostat, install the housing and tighten the bolts, and then fill through the expansion tank until the tank shows half-full. Leave the tank cap loose, start it up and let it idle until the thermostat opens (upper hose will get hot right away when it opens), then let it idle for another five minutes and shut it down. When it cools off, add coolant as required at the tank so it's half-full when cold, and you're in business.

I use a plastic radiator funnel with 1/4" holes drilled in the end - it stands up by itself in the thermostat opening, bottomed out in the hole; simplifies filling, and you can monitor the level as it rises in the manifold passage:

 

[bobmanx]

Thanks JohnZ, I thought that you and other C2 owners that are regulars here on the C2 area might have a easy way to get this accomplished and keep air out of the system. I will give it a try.

Thanks for the info, Bob

 

[jerrybramlett]

I just drill a 1/8" diameter hole in the thermostat.

 

[Hib Halverson]

Take it from JohnZ. He knows his stuff.

The method he lists is the way I've done coolant fills on Gen 1 SBV8s for as long as I can remember. It works quite well and eliminates most air in the system from the "get-go".

 

[bobmanx]

Hib and Jerry, I'm new to Corvettes, been raised on imports. There is a lot that is new/different and not wanting to cause myself any problems that could be avoided, I ask first and proceed with caution. JohnZ's and others responses are greatly appreciated. Thanks for the inputs...........

Bob

 

[magicv8]

When I worked for dealers in the 60s, I just put coolant in the expansion tank and ran the car. I still do it that way - no problems. I try not to make a technical TourDeForce out of things the service manual considers to be obvious.

Usually, owners look at a complicated procedure (like setting up the rear wheel bearings) in the service manual, and try to short cut the factory procedure. I am surprised to see it go the other way on coolant refill.

Having said that, I am the guy who uses a spin on filter so I can fill it before starting the engine. I don't do that on my new Pontiacs, only on my old Corvette.

PS All of the above is my o-pinion, and no offense is intended. I love the paint job on that intake Johnz.

 

[bobmanx]

Magic, thanks for the response, no offense taken and I'm sure none taken by others. Thats why I asked for C2 owners input as to what they do. I'm sure that there are more ways to refill a smallblock cooling system. What I wanted was info from people that work on their C2's and what did/didn't work from their experiences.

As I said, I'm new to Corvettes, but not to things automotive, imports, and not all water cooled. Still have a few air cooled but thats a different place. I really appreciate Corvette owners that maintain their cars responding to my and others questions about how to repair, maintain, restore, and modify Corvettes.

Thank you all for helping to educate the new guys, thats what the hobby is all about and makes the owner and wrench time more enjoyable.

Bob