Hello. I'm replacing both radiator hoses on my 68 Sport Coupe. The new lower hose does not have the spring in it to prevent collapse but the old hose does have the spring.
Is the spring no longer necessary? If so, would that be due to better hose materials?
Also, are the original tower type hose clamps reuseable or is it advisable to install new ones? Thanks, Joe.
I was running my 406 to do the cam break in and the lower hose without the spring was flattening and restricting coolant flow. The hose was new so it would probably be one of the improved design type. When you are driving there is no way to see if that is happening. I like to err on the side of safety and would hate to overheat an engine due to a $15 hose not performing as advertised. IMO the spring is being left out to lower production costs.
Fluid flows from top to bottom of the radiator where it's returned to the block.
A hot cooling system pressurizes to up to the psi rating of the rad cap.
Flow through the system is regulated by a thermostat.
What would cause the lower hose to collapse?
First vacuum would have to form within the system. To get a vacuum condition going I think the t-stat would have to be closed and the water pump bypass plugged. I guess a plugged radiator core could do it too.
Possibly a high volume water pump might pull coolant from the core faster than it can supply it.
Once an engine is up to temp and the t-stat is open there should be very little risk of collapsing the lower hose. I'm thinking it all comes down to a properly working system.
Here is the official word from Gates: ‘’Molded radiator hose construction has been upgraded with more robust compounding and thicker hose walls, this has negated the need for the spring in molded coolant hoses. Originally the spring was inserted @ manufacture to compensate for collapsing.’’
According to the comments that were received on this topic, it sounds like it would be a good idea to put in the spring anyway. Thanks for you input. Joe.
Weak bottom hoses are a common cause for running out on open road.
Yes DJD I do follow your logic, I even used to have the same opinion. ....till I got hit with the issue many yrs ago...even a stock pump draws enough water from the bottom and the radiator does have enhough restriction with this volume of water flowing thru to create a big enough pressure drop between radiator and pump to suck a weak hose in.
I cant rem the actual figure as to the galls/min a stock pump can put thu, but I do rem being very suprised....Smokey, yrs ago covered this subject....hence why he recommended a restrictor replace the thermostat if it is not used, otherwise there is enough water passing thru the radiator fast enough to have the temps to high at the bottom...water doesnt cool down enough.
I found this out when I had the soft bottom hoseandtrouble shooting, removed the thermostat and ran very hot.....
Found Smokeys notes, replaced bottom hose, still ran way too hot, put in a drilled thermostat, all fine....over the yrs come across exactly the same on peoples engines.
I don't know, but the stock replacement one I got from Advance felt like I could collapse it by putting my hand over one end and sucking on it. I've got a high flow pump so I gave it back and got the Gates flex hose instead which had a spring inside it. If you look at the lower hose for a '69 on Gates' website, it specs the flex hose.