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! Even sometimes at idle the hose would pulse. Now the ONLY thing I haven't replaced is the water pump and radiator. 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. The engine is not really over heating either, it stays at 1/2 way up on the temp guage and every now and then goes to 3/4 way up. It is not boiling over/steaming

My question is what do you think it may be?

thanks a ton
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