Radiator Hose

[timkins]

I have a 32 Ford with a 355 Chev motor that has a new Walker Radiator in it. I drove the car about an hour last night and parked it and opened the hood. After about 45 minutes I went to close the hood and noticed the upper radiator hose was flat. I cracked the radiator cap and released the vacuum and the hose returned to the normal shape. I drove the car and parked it and when I checked this morning the same thing had happened. I have never seen this before and my question is, is it normal? I have an overflow catch can but obviously the cap is not releasing to allow the water to flow in the can. Is there a remedy for this or just drive it.

[Charlie Chops 1940]

Faulty cap or the hose needs a spiral wound wire inside.

[unklian]

Try a different cap.

[wayne petty]

a few questions..

are you running a thermostat and some kind of bypass hose or circuit??

so the coolant inside the engine is actually circulating around past the closed thermostat until the coolant has picked up enough heat. then the thermostat opens and allows the coolant trapped behind the closed thermostat to be exchanged with the cooler coolant in the radiator.  the thermostat closed when the cooler coolant circulated past the thermostat.. allowing the coolant circulating inside the engine to pick up heat again.. so the cycle continues.. thru the bypass hose..

this allows the coolant stopped in the radiator to be cooled either by ram air or by the fans pulling or pushing air thru..

without a thermostat.. the coolant will circulate faster and faster as engine speed increases... the fast flowing coolant cannot be cooled by electric fans.. sometimes not by ram air thru the radiator..

this causes a runaway cooling system..

now.. lets talk about your flat hose issue..

as the engine warms the coolant..  the coolant expands taking up more space in the cooling system..  this is pushed out thru the coolant recovery type of radiator cap and into the coolant recovery bottle...

when the engine is shut off and starts to cool... the coolant contracts and pulls the coolant back into the radiator to keep it filled..

if your radiator cap is not allowing this reverse flow.. it will collapse the hoses as you describe..

please verify that with the radiator cap off.. that you can blow some pressure into the overflow tank and cause the coolant inside to refill the radiator..  

if you have a hand pumped brake bleeder pump.. you might try that..   if there is any sediment in the overflow tank.. or other junk.. it can plug the hose... if you are using clear vinyl hose.. you might want to search out some 9/32 windshield washer vacuum hose.. thats usually the correct material for this overflow and is usually stiff enough to prevent kinks and collapsing..

if your radiator is partially empty.. or you have drained it slightly. you can blow into the overflow hose with the cap on to verify the pressure required to reverse the flow..

if you have a radiator pressure tester with the radiator cap adaptor.. and a hand vacuum pump..   yep thats a LOT of tools..  you can apply vacuum to the radiator cap to check the reverse flow..

some radiator hoses are too thin for proper operation in a coolant recovery system without an inner spring to stop the collapse..

lastly.. do you have any empty easy to swap coolant passage threaded ports in your manifold.. to see what's happening.. in the cooling system... one could use with clamps on the hoses... a 50 or 100 pound pressure gauge..  as there is mechanical pressure built up behind the closed thermostat that actually increases the boiling point of the coolant needed around exhaust ports and exhaust valve guides to prevent localized overheating from pushing the coolant out the bottom hose  and into the revcovery tank..

[Mikej]

You might not have enough water in the radiator. Normally the cap opens and water goes to the overflow. When it cools it sucks it back in. Sound like it is opening and letting steam out but not opening to let air or water back in. Could end up collapsing your upper tank.

[Arnold]

a few questions..

are you running a thermostat and some kind of bypass hose or circuit??

so the coolant inside the engine is actually circulating around past the closed thermostat until the coolant has picked up enough heat. then the thermostat opens and allows the coolant trapped behind the closed thermostat to be exchanged with the cooler coolant in the radiator.  the thermostat closed when the cooler coolant circulated past the thermostat.. allowing the coolant circulating inside the engine to pick up heat again.. so the cycle continues.. thru the bypass hose..

this allows the coolant stopped in the radiator to be cooled either by ram air or by the fans pulling or pushing air thru..

without a thermostat.. the coolant will circulate faster and faster as engine speed increases... the fast flowing coolant cannot be cooled by electric fans.. sometimes not by ram air thru the radiator..

this causes a runaway cooling system..

now.. lets talk about your flat hose issue..

as the engine warms the coolant..  the coolant expands taking up more space in the cooling system..  this is pushed out thru the coolant recovery type of radiator cap and into the coolant recovery bottle...

when the engine is shut off and starts to cool... the coolant contracts and pulls the coolant back into the radiator to keep it filled..

if your radiator cap is not allowing this reverse flow.. it will collapse the hoses as you describe..

please verify that with the radiator cap off.. that you can blow some pressure into the overflow tank and cause the coolant inside to refill the radiator..  

if you have a hand pumped brake bleeder pump.. you might try that..   if there is any sediment in the overflow tank.. or other junk.. it can plug the hose... if you are using clear vinyl hose.. you might want to search out some 9/32 windshield washer vacuum hose.. thats usually the correct material for this overflow and is usually stiff enough to prevent kinks and collapsing..

if your radiator is partially empty.. or you have drained it slightly. you can blow into the overflow hose with the cap on to verify the pressure required to reverse the flow..

if you have a radiator pressure tester with the radiator cap adaptor.. and a hand vacuum pump..   yep thats a LOT of tools..  you can apply vacuum to the radiator cap to check the reverse flow..

some radiator hoses are too thin for proper operation in a coolant recovery system without an inner spring to stop the collapse..

lastly.. do you have any empty easy to swap coolant passage threaded ports in your manifold.. to see what's happening.. in the cooling system... one could use with clamps on the hoses... a 50 or 100 pound pressure gauge..  as there is mechanical pressure built up behind the closed thermostat that actually increases the boiling point of the coolant needed around exhaust ports and exhaust valve guides to prevent localized overheating from pushing the coolant out the bottom hose  and into the revcovery tank..

 Very good points Wayne!A lot of people just do not understand this.
I remember when it was thought to be better to take out the 'stat.
Sure..and that is why they started making restrictor plates to go in place of the stat
 When I was involved with taxi fleet maintenance..a lot of cab owners would take out the stat..then pretty much spend a fortune replacing the entire coolling system..being sold heavy duty this and that..
most of the cars were propane and ran like crap after that because the convertors were hot water powered..and needed the hot water trapped in the block for longer.Then  someone would put the stat back in
 Winter was the best time for this..IF it was cold enough..the car would start fine with what was left in the convertor..IF it stalled..then the plugs would ice up and could not even be removed.
 Gradually poured water..gradually warmer..into frozen engines to thaw them out..heaters under the car..in the engine compartment.Some just had to go inside to the warmth.
 Thanks for the memories

[timkins]

Thanks for the replies and suggestions. I added about a quart of water as the radiator was down and then I put a new radiator cap on but the weather has not been helpful to check and see if this was the problem. It has been raining for the past week here in upstate New York. Again thanks for the suggestions and I will let you know what happens when the weather breaks.