Cooling System

[Timothy B.]

Re: Cooling System

Leif,

The car does not have it's original style radiator, you only need one radiator cap (RC-26) and that should be on the supply tank. IMO, it looks like the radiator overflow tube is connected to the supply tank but the cap in the radiator should be defeated. If the coolant expands in the radiator it should flow into the supply tank so the radiator is not damaged.

Look for some pics of cars with the original radiator and supply tank to see what the set up should look like.

See what others say about this set up, I guess if the radiator pressure cap opens fluid will flow to the supply tank so it may be fine as is.

[Steven B.]

Re: Cooling System

And the water should be distilled. Steve

[Leif A.]

Re: Cooling System

Tim,

It's definitely a replacement and your comment about "if the radiator pressure cap opens fluid will flow to the supply tank" makes complete sense to me. Interested to see who else chimes in and what the consensus will be. Thanks for your valued insight.

[Duke W.]

Re: Cooling System

It looks like Micky Mouse designed that setup. To which nipple on the expansion tank does the radiator cap overflow hose go to, and where does the expansion tanks other nipple's hose route to.

The overflow nipple on the expansion tank is open to the atmosphere unless the cap relief valve opens up.

I recommend you look into A Dewitts ...316 radiator.

Duke

[Roger G.]

Re: Cooling System

It looks like Micky Mouse designed that setup. To which nipple on the expansion tank does the radiator cap overflow hose go to, and where does the expansion tanks other nipple's hose route to.

The overflow nipple on the expansion tank is open to the atmosphere unless the cap relief valve opens up.

I recommend you look into A Dewitts ...316 radiator.

Duke

mickey%204.jpg"Aww gee whiz, all you do is put it together"

[Leif A.]

Re: Cooling System

Duke,To answer your question, the actual radiator cap over flows to the supply tank 1 o'clock nipple (in the picture). The 3 o'clock nipple's hose routes down by the frame for any excess overflow (expansion). I didn't do the restoration on this car but the setup seems to work. Esthetically it may not look correct and it sure wouldn't win many flight points...but it does work. So, the question remains...the radiator has the RC-26 15# cap and the tank has the RC-15 15# cap, is the radiator going to be safe? When this radiator has any issues, I will certainly look into a Dewitt 316 radiator...thank you.

[Michael W.]

Re: Cooling System

It looks like someone has attempted to re-purpose a supply tank as a coolant recovery tank. As configured, it won't do much in that respect as there's no way for the coolant to be drawn back into the rad after shutdown..

[John C.]

Re: Cooling System

the actual radiator cap over flows to the supply tank 1 o'clock nipple (in the picture). The 3 o'clock nipple's hose routes down by the frame for any excess overflow (expansion).

Leif

If the 3 o'clock nipple on the supply tank is being used to release excess coolant from the system, your radiator system is not even pressurized. This nipple is directly open to the atmosphere.

You can probably get away with the crazy system you have, but to be pressured the overflow from the radiator must go to the 3 o'clock nipple on the supply tank. The nipple at 1 o'clock on the supply tank should be used to pressure relive the system to atmosphere.

John

[Duke W.]

Re: Cooling System

Duke,To answer your question, the actual radiator cap over flows to the supply tank 1 o'clock nipple (in the picture). The 3 o'clock nipple's hose routes down by the frame for any excess overflow (expansion).

As others have stated, I don't see how this can work satisfactorily. Having the nipple at 3 o'clock open to the atmosphere means the system won't develop any pressure. I expect it must lose coolant every time you drive and leave coolant drops under the car when you park. In OE config. this nipple is connected with a hose to a nipple on the top RH side of the Harrison radiator. Its purpose is to vent vapor to the expansion tank.

A 50/50 antifreeze/water blend boils at about 230F at sea level atmospheric pressure. A 15 psi cap raises it to about 265F.

The 1 o'clock nipple is also open to the atmosphere unless the pressure relief valve opens up.

If you reverse the hoses, it should work better. Make sure the cap on the radiator is firmly seated and never open it again. Check/add only from the expansion tank cap.

Many owners who have a copper radiatior in place of the OE Harrison or DeWitt's reproduction report high operating temperatures because a copper radiator of the same dimensions has about 30 percent less heat transfer capacity.

Duke

[Leif A.]

Re: Cooling System

John and Duke,

I will reverse those two hoses...your information is very much appreciated and once explained by both of you, it makes logical sense. Thanks to all for your insight and kind assistance.

[Michael W.]

Re: Cooling System

I'm not sure I agree or possibly I don't follow one of the subtleties.

If the rad has a 'regular' cap on it, the system will pressurize just fine. If the rad is overfilled or the system pressure exceeds the cap's rating, air and/or coolant will be released via the tube leading to the external tank. Assuming the cap and tube connections on the external tank permit the flluid to enter, the tank pressure will increase up to the rating of that cap at which point it too will release but this time dumping coolant on the ground.

What's not clear is after the initial release of coolant to the external tank, how does the coolant return to the rad after the engine is shut down and allowed to cool? As it stands, I believe only air will be drawn back to the rad head space, making the external tank ineffective and redundant.

[Leif A.]

Re: Cooling System

Great point, Michael. I'll be awaiting a response...learning something new every day

[Joe C.]

Re: Cooling System

The following only holds true if the heater hose is no longer teed into the bottom of the tank and the 5/8" nipple is plugged or capped.

You have to connect the lower 1/4" hose from the former supply tank, but now expansion tank to the nipple leading to the radiator cap, and replace the radiator cap with a "closed system" type, or convert the "open system" cap to a "closed system" cap. Once you do this, you can either cap the upper 1/4" nipple on the former supply tank, but now expansion tank or run the hose down between the frame rail and the inner fender. If you cap the upper nipple then you'll need a tank cap that's vented; if you run a drain line, then you can use your RC-26 cap.

Fill the newly created expansion tank about 1/2 empty or 1/2 full depending on your state of mind.

If you're looking for originality than you need a new radiator, and you also need to lose the splash shield on the compressor.

If you want to know how to convert an original "open system" style rad cap to a "closed system" style cap, then contact me privately.

[John C.]

Re: Cooling System

I'm not sure I agree or possibly I don't follow one of the subtleties.

If the rad has a 'regular' cap on it, the system will pressurize just fine. If the rad is overfilled or the system pressure exceeds the cap's rating, air and/or coolant will be released via the tube leading to the external tank. Assuming the cap and tube connections on the external tank permit the flluid to enter, the tank pressure will increase up to the rating of that cap at which point it too will release but this time dumping coolant on the ground.

What's not clear is after the initial release of coolant to the external tank, how does the coolant return to the rad after the engine is shut down and allowed to cool? As it stands, I believe only air will be drawn back to the rad head space, making the external tank ineffective and redundant.

Michael

Normally the supply tank is teed to the heater hose. This is how the overflow into the supply tank is returned to the system. This is also how any pressure in the system would be lost if the overflow hose is connected to the 3 o'clock nipple on Leif's supply tank.

Leif, to understand how your system is working we need to know if the supply tank is still teed into the heater hose.

John

[Joe L.]

Re: Cooling System

Great point, Michael. I'll be awaiting a response...learning something new every day

Leif------


My recommendation on this is quite simple: obtain a DeWitts reproduction of the GM #3155316 radiator and return your cooling system to completely stock configuration. Yes, the radiator is expensive but it's the only configurationally and functionally correct way to go.

Trying to "Rube Goldberg" the already "Rube Goldberg" set-up you have is foolhardy.