Overheating issues

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Still need to have your overflow canister vented to the outside air to allow expansion coolant to move freely into it, and also allows coolant to freely return to the radiator when it is cooling back down.

Right now you have a 100% pressurized system, making it hard for expanding coolant to get out, as the overflow canister is pressurized too without being vented to the outside air.

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George Jets said:
Right now you have a 100% pressurized system
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BTW with out a vent you have a bomb. The pressure will build to well over cap pressure then something will give.

The rad core?
The tank seams?
Freeze plugs?
Hoses?


I have been burnt on my arm with boiling radiator fluid, not fun.

You would be better off to remove any recovery system and just keep an inch of air above the coolant in the rad top tank.
 
Now you all have new wondering about my overflow it has a cap on it but not sure if its vented well enough. Here's the one I have.

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Matts440 said:
Now you all have new wondering about my overflow it has a cap on it but not sure if its vented well enough. Here's the one I have.

View attachment 1716113316
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Pop that little hose off at the radiator and blow in it. You'll know right away if it's vented or not. If it's not, drill a small hole in the cap to that overflow bottle or in the bottle itself.
 
Still need to have your overflow canister vented to the outside air to allow expansion coolant to move freely into it, and also allows coolant to freely return to the radiator when it is cooling back down.
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Forgot to mention, I left the overflow off yesterday.
 
mopowers said:
Pop that little hose off at the radiator and blow in it. You'll know right away if it's vented or not. If it's not, drill a small hole in the cap to that overflow bottle or in the bottle itself.
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Thanks my friend tested it tonight and no venting, will swap the fitting to the bottom to pull or overflow into it and drill a vent hole through the cap or just cut the bottom part off and let the side hole where I did have it connected open.
 
I do not know why everybody is concentrating on the overflow. Nice to have one, but the lack of one is not causing the OPs problem.
 
It was about 90 degrees yesterday and I drove it a bit around town. It did start to overheat, but the system is filled with the cleaner and mostly water.
 
Summit carries one for about $84. This is the same one that I have used on start up and through break in. You may or may not be surprised at what it catches. Later on I removed it and reinstalled the regular hose. It's your new radiator, but you have already driven it.
 
To say a system is not vented when it has a pressure release cap simply isn't true. The pressure valve on the cap IS the vent. As for the overflow tank, the same applies. If it has a pressure release cap, it IS vented, it is just NOW an extension of the radiator tank.
 
RustyRatRod said:
To say a system is not vented when it has a pressure release cap simply isn't true. The pressure valve on the cap IS the vent. As for the overflow tank, the same applies. If it has a pressure release cap, it IS vented, it is just NOW an extension of the radiator tank.
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If the cap is vented to the overflow and the overflow is not vented would the system be vented?
 
92b said:
If the cap is vented to the overflow and the overflow is not vented would the system be vented?
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The radiator is vented to the overflow. The overflow is not vented. "Most" overflow tanks are not completely sealed. Their caps fit loosely, so they are not completely sealed and they do vent, even if not designed to do so. There are some aftermarket tanks like the little plastic ones Summit sells with the drain valve on the bottom are not vented at all but are completely sealed, but the radiator vents TO the overflow tank, so the radiator in those cases is vented, just not the overflow.
 
RustyRatRod said:
The radiator is vented to the overflow. The overflow is not vented. "Most" overflow tanks are not completely sealed. Their caps fit loosely, so they are not completely sealed and they do vent, even if not designed to do so. There are some aftermarket tanks like the little plastic ones Summit sells with the drain valve on the bottom are not vented at all but are completely sealed, but the radiator vents TO the overflow tank, so the radiator in those cases is vented, just not the overflow.
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So if I understand post 82 correctly functionally he has a closed system.
 
92b said:
So if I understand post 82 correctly functionally he has a closed system.
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If he is using a standard radiator cap with a pressure relief valve, it's closed but vented through the cap.
 
This is interesting, a 2003 Dodge Caravan Overflow Tank with a high water Neck/Vent.

So same way the Caravans are set up, Vented Radiator Cap that allows expanding hot coolant into the Vented Overflow Tank.

So this setup would be a vented system.

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RustyRatRod said:
To say a system is not vented when it has a pressure release cap simply isn't true. The pressure valve on the cap IS the vent. As for the overflow tank, the same applies. If it has a pressure release cap, it IS vented, it is just NOW an extension of the radiator tank
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The radiator cap is vented no argument there.

BUT... If the overflow bottle does not have a vent or a pressure cap then the entire system is no longer vented.

On top of that, if the overflow cap is a pressure cap at 16 lbs and the rad cap is 7 lbs the system is 16 lbs
 
Dana67Dart said:
The radiator cap is vented no argument there.

BUT... If the overflow bottle does not have a vent or a pressure cap then the entire system is no longer vented.

On top of that, if the overflow cap is a pressure cap at 16 lbs and the rad cap is 7 lbs the system is 16 lbs
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The radiator vents at 7PSI.
 
RustyRatRod said:
The radiator vents at 7PSI.
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For the system to work properly The radiator has to be able to displace an indefinite amount of expanding fluid or the pressure will rise above rating of the cap. A system without a vent in the overflow tank can't do that. When the pressure in the radiator vents into the tank it equalizes the pressure between the two. When that happens any additional expanding fluid will cause the pressure in both the radiator and the tank to rise until it finds the weakest point in the system and makes it's own vent.
 
The overflow tank is vented. It is atmospheric pressure, acting through the vent, that 'pushes' the coolant back into the rad.
 
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