Was surprised that the new hose did not come with the coiled wire that keeps the hose from collapsing. The store said they do not have them any more.

http://automotivemileposts..../moldedhosecoil.html

Original equipment molded radiator hoses often were equipped with a coil inside them. Some refer to this coil as a spring, but it isn't really a spring. Actually just a piece of thin metal rod that has been twisted, it was designed to facilitate the installation of coolant on the assembly line, and nothing more.

When the cooling system of a car is completely drained, or in the case of a brand new car under construction, never had coolant in it, there is a considerable amount of air in the passage ways. Normally, when filling up the cooling system, you start the car to circulate the coolant, displace trapped air, and then top it off. On the assembly line, this wasn't feasible, so air in the cooling system was evacuated by essentially pulling a vacuum on it. This also had the added advantage of speeding up the introduction of the coolant mixture to the cooling system as well. The coil in the lower radiator hose prevented the hose from collapsing under this higher than normal vacuum.

Once the car left the factory, the coil served no further purpose. This is why replacement hoses usually do not have a coil in them. Most cooling systems operate at 12-15 P.S.I., which is controlled by the radiator cap. This is enough pressure to allow a normally functioning cooling system to operate efficiently, yet not enough to cause collapsed hoses or leaks in seals if they're in good condition. If the lower radiator hose collapses, it is normally due to a fault somewhere else in the system, and is not necessarily indicative of a bad hose, although an old hose certainly might be susceptible to collapse due to age. Normally, if the hose is in good condition but collapsing and blocking the flow of coolant, the radiator cap is bad or there's a blockage somewhere else causing pressure to build up in the cooling system.

As vehicles with original hoses began to age, the coil would sometimes begin to corrode and deteriorate, circulating tiny pieces of metal throughout the cooling system. We'll leave it to your imagination what this did to water pumps and thermostats.

Having worked in my father's auto shop from a very young age, and then working with my own hands on 50s and 60s vehicles as a young teen, I can tell you that regardless of what that article states, replacement lower radiator hoses DID indeed come with the "spring" in them from the mid/late 50s thru the 60s.

I think it is a feature of the modern pressurized cooling system. I read hundreds of old mechanics books going back to the 1910s, and I remember the mystery of the overheating hotrod. The cooling system looked fine, timing, mixture, and everything looked and tested good. The "hero" mechanic decided to rev and run the RPM to the owner would. Sure enough, the lower hose was sucked closed. Installed coil/spring was installed and problem settled. Pretty sure the magazine was from the mid 50's and the car was a pre war with a post was motor. That would be long before pressurized systems.

quote Originally posted by maryjane: replacement lower radiator hoses DID indeed come with the "spring" in them from the mid/late 50s thru the 60s.

I had installed some lower hoses from late 70's and in to the 80's that had "springs" in them too.

Kevin

At many shops (including ours) when a cooling system is refilled after repairs, we use an "air lift" device which operates the same way as the assembly plants' equipment mentioned in the article. We have found that with most newer cars, the hoses are often quite short or at least do not have any long, straight sections which are where the older hoses tended to collapse if they didn't have an internal "spring". The sharp bends and even built-in tee or y-connections are usually rigid and tend to resist collapsing under vacuum.
I assume that the spring is no longer necessary in these hoses.