Ok I now own this ford ranger 88 2.9 litre, and at first my top radiator hose was collapsing when the engine was shut off and cooled down. Well I replaced the thermostat, upper hose, and radiator cap and that stopped that problem.
Well today I was out messing around under the hood checking things out and I decided to rev it up by the throttle body. While reving it up I noticed the TOP radiator hose is collapsing, and the more rpms you gave it the tighter it would collapse! Now the ONLY thing I haven't replaced is the water pump. The pump that is on it MAY be original since it says motorcraft on it. However I really dont see how a new water pump would cause this problem to stop.

My question is what do you think it may be?

thanks a ton
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same problem here with the collapsing hose . . . . since my theory of it being an old hose that just can't hold up and collapses under pressure anymore has just been debunked . . . i hope someone can help us out lol
how dangerous to the cooling system is/can this be?

 

Well I replaced the upper hose with a new one but not the lower because I didn't have time at the moment and had nothing to catch my antifreeze. The lower one I am not having a problem with collapsing, its the top new hose

 

You probably need an anti-collapse spring inside the hose. Some hoses are very robust and resist collapsing better than others.

The lower hose can collapse from engine vacuum. Anything that restricts your cooling has the potential to damage the engine.

 

Well The top one shouldn't do that since its not the suction hose right? If anything the lower one should collapse, not the top since the water pump pulls water from the radiator to the lower hose, up through the engine, and back up through the top hose into the radiator. I don't see how it would be a reverse water pump either since the top hose gets WAY hotter then the lower hose. Meaning its a normal rotation pump. I am just cluless on why the top hose would collapse!

 

ditto

its my top hose thats collapsing like when you suck on a straw inside of a wendy's frosty . . . its just gets real skinny . . . totally baffled as well

 

If you look at older cars, you will find many that had springs inside the upper radiator hose. The upper hose lives in a harsh environment since the themostat blocks coolant from flowing through it until the engine is warmed up. In any case a spring will address the issue.

 

when u take the rad cap off does the hose spring back. the rad cap is supposed to let the system suck in coolant from the recovery tank. if the hose seems fine (top rad), then check the small rubber hose to the inlet on the rad (take it off and blow a small burst of shop air through). if thats fine then replace the rad cap. only try this if u r sure that the hose is fine. a spring will not fix the problem. either replace the hose or find the problem. then if you want to waste your money and time on a spring go ahead but if you just add it now you may be masking another problem.

 

If you are talking about the "small hose" that leads from the filler neck of the radiator to the overflow bottle I have made sure that was free of obstructions and even disconnected it with the engine running one time. Still same results (collapsing Upper rad hose, while reving), I also replaced the rad. cap with a new one. I guess there is always a chance of a bad cap though... I would rather not put a spring in the top hose since there is obviously a problem and I don't want to have a bigger prob down the road like you said..

 

it sounds to me like there is a restriction in the head or pump itself that is causing to much pressure differential. is all the air out of the system? try taking the thermostat out and seeing if the problem is still there. do you get lots of heat out of the cab heater? *first* try pinching off one of the lines to the heater core (pass side firewall) and see if that makes a difference if it does then the passage from the water pump to the head is restricted and the flow is comming from the pump through the core through the head and to the rad. let me know what happens please. this is a long shot but in theory it could happen.