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Radiator hose air bleeder



I was reading an article on the 'sharkwerkes' site about cooling system tips and air in the upper radiator hose on the C3's. I have had some overheating problems on a '68 and I think I may have this problem and wanted to see if anyone knew anthing about a bleeder valve. I have been unable to find anything on the web. The article was written by a Larry Barickman, a.k.a. silvervetteman. If anyone knows anything about this or where to find bleeder part for a radiator hose please let me know,
bleedin' air

I'm just a girl...but couldn't you achieve the same thing by elevating the front end of the Vette, and elevating the upper radiator hose/cap side a little higher as you fill it? It may not get ALL of the air, but would not be a weak link in your cooling system, either.
(plumbing, every fitting is another leak waiting for the right pressure to happen)
Re: bleedin' air

78SilvAnniv said:
I'm just a girl...

:L That's ok, Heidi. ;)

Seriously, I just read somewhere about elevating certain cars when performing the brake bleeding procedure, and I don't see why that couldn't help when bleeding the cooling system. At least it can't hurt. :gap
Thanks for the advice. I had not thought of elevating the car when filling. The whole problem comes in with the fact of not having a cap on the radiator and filling through the expansion tank.
other methods

There are other ways of getting the air out without having to lift the car on its side.

1. take off the cap when the car is cool, start the car and have someone rev the engine to about 1500 rpms or so. If you look inside the radiator you will see the level of the water drop. Fill until full, whatever is left over will go to the overfill tank. Its possible to force the air out that way

2. you can bend the tubing downward and force the air to go into the radiator and clear it out that way.

or you can do both at the same time.

also check of you have a bad or old clutch that could cause overheating. Sharks are known to run hot about 210 on average though ideally you want it to be about 180-190

hope that helps


Your cooling system should self-purge itself of air if all the hose connections are correct and not leaking. Each time you run your engine the heating of the cooling fluid will cause it to expand. This causes the radiator cap to release the pressure and force liquid or air (when present) into the expansion tank. When the system cools the fluid contracts, the small reverse flow valve in the center of the radiator cap releases and fluid flows into the system from the expansion tank.
If you examine where the flow from the expansion tank to the radiator is located in the tank, it should be below the level of the coolant in the tank preventing it from allowing air to return to the radiator. This insures that eventually these cycles will remove virtually all the air from your system. If your radiator cap, any hose or other component leaks, this may allows air to re-enter when the system cools and the air will not be purged.
If you monitor the level in your expansion tank, it should rise when the engine is warm and fall when it is cool. Showing that coolant is being pumped in and out by the expansion and contraction of the coolant. If you do not see this happening you should look for leaks in the system.
There should be no need for a purge valve on a system with an expansion tank when the system is working properly. Let me know if you have a problem checking your system for proper operation.

Since the upper radiator hose is above the level of the radiator cap I suspect that the system will not self-purge completely. I've tried raising the front of the car with some sucess. My diveway is at an angle too so my car was raised a lot from level. With raising the car and pushing the upper hose down you can get the system closer to full.
My mom's 1990 Lumina has about 3 real cool looking purge valves that screw into the water outlet neck, block and heater connection, but I'm not sure what use they would be in the case of a C-3.
This may help

I saw a couple of interesting posts this morning by GreyGhost on the Aftermarket Review board that I printed off to save. One was Filling Your Radiator and the other was something like Cooling Sytem Troubleshooting Tips.

I just love this place!

72 Bluz
As I had cooling system issues a short time back I did some research myself on this topic. Many new cars do have a oneway valve for bleeding air but I checked with Chevy dealer and not one available for older cars.

Raising the car is one method. Another and what I did is to remove the thermostat housing while filling the radiator until the fluid starts to flow out of the thermostat housing on the intake manifold. Then reattach thermostat and housing. Furthermore, your thermostat has a very small bleed opening in it. I drilled this bleed opening just a little to make sure air could move from behind thermostat. In most cases air should purge from system but not always.


Another way

There is another way to fill your cooling system that will eliminate most of the air pockets. First fill the system as much as you can in the normal conventional way. Turn your heater on and disconnect the heater hose. Fill the system to max through the heater hose. This is usually the highest level in the entire cooling system and will insure you obtain maximun fill results. Reattach heater hose and make sure the expansion tank has enough coolant in it to do it's job. Periodically check the level in the expansion tank after a few hot to cold cycles. All air should be eliminated through these cycles.

Thanks for all the advice. I was able to get some air out by disconnecting the overflow hose from the radiator to the expansion tank. I'll have to wait for some more hot weather to see if she runs any cooler then. Thanks

Unless you let the water mixed with the coolant in your system was allowed to sit out for a few hours, it will have air dissolved under the pressure of your water lines. This air will be released from the water for a period of time and will appear even if it looks like you have it all out. Remember the bubbles from nowhere in the old waterbed, or the bubbles that form in the ice cubes. So it is very important that you keep checking the level in your expansion tank since the cooling system will drink coolant during the period it takes to release all of the air that was in the city water. As for any tubing above the radiator cap, this is common. One reason to turn your heater on high is to obtain coolant flow through it. The movement of the water "entrains" the air and carries it through the system. As the coolant flows though the radiator, its flow slows due to the larger cross sectional area. This causes some of the air to escape the entrapment and float up to the radiator cap, thus purged on following cycles. Finally purging the complete system over time. Now some systems have had design flaws, but I do not believe your vehicle is one of them.


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