Upper Rad hose quite hard ( Issue? )

[Barry_Calgary]

Hi All,
My 440 73 Roadrunner seems fine and does not overheat and in fact with my 160 t-stat
it runs a little on the cool side. What i'm curious about is the upper rad hose gets quite hard
after being driven up to operating temp. I thought that perhaps the rad cap may need to be changed as it has a 14-16 PSI cap so I bought a replacement and the hose is basically the same. T-stat and rad are basically new.
Is this typical as the bottom hose is a lot cooler and you can squeeze it quite easily.
Thanks

 

[multimopes]

Not sure about the upper hose getting hard. Are you thinking the cap is sticking closed? Is the rubber old and dry or does it have on internal spring? I do know that the lower hose being "squeezably soft", can lead to a potential overheating problem. I have had that problem years ago. It rears it's ugly head when you are at highway speed and it sucks flat and you notice your temperature gauge going up. So you pull over and check under the hood and at idle it looks normal. All you need to do under that circumstance to see it is to manually open the throttle and that's when you see the hose suck in restricting coolant flow. I would recommend changing out your lower hose with a reinforced one before you get this unexpected surprise. There is conflicting info here in the heating and cooling forum regarding using a 160 degree stat. Many say it should be a 180. It's a matter of choice as we oldsters used to put 160's in for summer and went back to a 180 for winter.

 

[PurpleBeeper]

When the engine is warmed up, the cooling system is under about 15psi of pressure, so the hose(s) inflate like balloons. So, if the upper hose is hard when hot & flexible when cool you don't have a problem (unless it's a very, very old hose). What multimopes is saying is true about the lower hose. The cheap ones don't have a spring & the good ones do have a spring. (coil of thick wire inside that you could pull out with your hand if you pulled really hard). You want the ones with the springs inside. Otherwise, when the hose gets old/soft it can "suck in" and block off your coolant flow.

 

[Barry_Calgary]

Sounds good thanks for the replies, I was just worried about how hard the upper hose is when hot, as far as the bottom hose I will have a look at it, would I be able to feel the spring inside when squeezing it?

 

[multimopes]

Yes, if it has one and hasn't corroded away. If you feel it break when squeezing you better change it before starting the engine. I (had) a real good one a few years back where the spring was not just inside the hose, it was inside the rubber wall of the hose. You could not see it. The hose was sort of corrugated with smooth ends that you could cut a few inches off either end. If you go to buy a replacement hose and they tell you they don't make one with a spring; you're being hosed!