I replaced the upper and lower radiator hoses on my 91RS 5.0 two years ago and they collapse after extended driving. There is ample fluid in the overflow tank and radiator, no leaks, does not run hot (180+- w/cool fan switch and t-stat+ chip mod). Upper and lower get warm as if coolant is flowing. When she sits over night the hoses appear okay. Normal or just crappy / soft upper and lower hoses? Could the water pump be the culprit, radiator or what? Thanks for the advise!

IIRC, those hoses should have the wire/spring-type support inside them, correct?

JamesC

JamesC, thanks for the reply.

Neither the upper or lower hoses have the sprial wire. Probably doesnt help them keep their shape. I'll check on some new replacements and keep that in mind when selecting hoses.

I checked the car after it sat over night and the hoses were still deformed, collapsed. Unscrewed the radiator cap which relieved pressure and the hoses returned to their correct form. Could the radiator cap pressure rating be too high? It's a 16lb, and the book calls for a 15. Could it be so simple? Probably replace that too.

Thanks for the feedback.

Same thing happened to me. I just got hoses with springs in them and it fixed the problem.

Same thing happened to me. I just got hoses with springs in them and it fixed the problem. Whoops sorry for the double click/post

Where did you get your hoses from? Gates no longer carries a lower rad hose for my car with a spring in it. They said the compound used for the newer hoses is good enough. I have a high flow pump and mine were collapsing so I am using the gates hose and transferred the spring to the new one and a flex hose on top. However I have gone to a 22psi cap and the flex hose is bulging. I will have to switch to braided line hose or custom fab one.

IIRC, Carquest carries them--or they used to.

JamesC

Yes, the lower hose number is 21324 but I just went to buy one and it no longer comes with a spring. I emailed gates and they said no more springs. The compund they use now should not collapse the hose. Thats what they told me.

If it's a problem, you can buy the springs separately..

Where at?

I'm trying to remember where.

LOL...I checked everywhere and all the parts stores here dont carry any.

It wasn't specifically for an automotive application, it was bulk lengths of anti-collapse spring at an industrial supplier somewhere.

Did anybody find a hose with a spring yet or find where to purchase the spring at? My car has been doing this with the lower hose at WOT.

Only the inlet hose to the water pump requires a spring-supported hose. I'm too new to the 3rd gen scene or I'd tell you if that is the upper or lower hose...usually the lower one though. The pump creates a suction in the connecting hose...without the spring it will collapse and could cause engine overheating. The other hose (usually upper) does not require a spring. I'm sure you could use one if you wanted but I think its better not to.

The lower hose should have a spring. The spring is needed if the water pump is pumping so hard it sucks it the lower hose shut--the upper hose has pressure from the pressure side of the pump. If the hoses are collapsed while it cools down, check the overflow hose and overflow container...to make sure they aren't plugged. If not, replace the cap. The cap should allow flow from the overflow container as the antifreeze cools down and creates a vacuum in the cooling system--I think this is your problem. This could happen while it's running as well....cooling system creates enough pressure to push past the cap...then cools down and wants it back. Working correctly, it also helps keep air out of the cooling system. The PSI of the cap is how much pressure it takes to allow antifreeze out of the cooling system to the overflow (what you need is the other way around), so the PSI should not be a factor.