The line going from the water pump to the radiator keeps shriveling up like all the water is being sucked out of it. It make a horrible sound as a burst of water (or maybe air that got stuck in the lines) bursts through then stops and shrinks again, much like sucking on a straw that is clogged. I replaced the radiator because it had a hole so I dont think thats the problem. I'm thinking it might be the water pump but I'm not sure. I'm trying to take it off but I'm having a little trouble with the last bolt under the crank pulley
( https://www.rx7club.com/2nd-generation-specific-1986-1992-17/water-punp-crank-pulley-help-629448/ )

Any help would be great.

 

I was going to say air.. but on a 91, it typically works itself out pretty well.... Make sure yout t-stat is working correctly. Probably not your water pump, if its creating a vacuum, its pumping... Have you done anything to your cooling system lately?

 

i had a small leak and i put some StopLeak in there but when i put the new radiator in i dumped out all the old coolant and put new in. I thought there was air in there too so i filled the over flow to normal and put some directly into the radiator. I took the radiator back out today to look at the water pump. I dont have anything after market on it.