All four rad. Hoses sucked tight!?

jakesbackyard

jakesbackyard

Member
So I go out to the shop and notice the radiator hoses are sucked in tight. The motor had just cooled down (2hrs) after a five mile cruise. See previous thread. What the heck is going on? Any ideas? I also lost 3 oz. of oil out the breather on the cruise. (another previous thread) I have a pop can tucked under the vent to catch it. I'm trying to figure out the overheating problem before I tear off the pan.

I loosened the rad cap to relieve the hoses. It started right up. One thing keeps leading to another and I'm guessing that one small (or large) problem might be the cause of all. Any ideas?

Thanks, Jake
 
With a little searching I guess I found the problem. When a warm engine cools a vacuum is created and sucks the hoses in. Since I made my cap air tight and have one of Skip's valves on the overflow it created a vacuum. I guess I'll have to find a low pressure cap for it to relieve the vacuum on cool down.
 
Its a simple fix leave off the band aid 3 lb valve. If you are worried about loosing coolant during high speed operation just install a coolant recovery tank. The radiator has to have a vent of some kind.
 
A vented pressure cap and even if it is over the 3# it doesn't matter the Skips 3# valve will relieve the pressure and vented cap will take care of the vacuum problem.
Vergil
 
You probably have Skip's pressure valve on your radiator overflow pipe with a pressure cap. As the engine cools a vacuum forms in the radiator tank sucking the hoses in as air can't get past Skip's valve. Just release the cap and they will go back to normal. Always check before you start up as the fan will hit the hoses, as least it does on my `35.

Shadetree
 
Wait a minute - most normal caps have a valve to allow air back in as it cools - if a coolant recovery setup is used, it sucks the coolant back in.

Just use a normal cap in good working order and it should be ok.

It's normally a smaller lighter flap valve in the middle of the cap. You can normally lift it with your fingernail to see if it is stuck.

Mart.
 
I'm with Dick on this one...You're referring to your 35 right? There is no relief valve built into an original 35 radiator cap. Toss the 3 lb relief valve gizmo on the overflow and run the overflow into a catchcan. This will mean your entire cooling system is always full. Brian
 
....and if you want to be relieved of your relief valve, I could sure use it on my Model A....
 
You must log in or register to reply here.
Back
Top