Hi, hope I can help. The pump is sucking in air on the intake side. There are a few possibilities where this can happen.
There is an o-ring under the fitting where the inet hose attaches, many times that leaks after distrubing the pump. The other possibility is the pump shaft seal, if the seal is dried out and the belt is a little too tight it will suck air in past it, especially cold.
Check the nipple o-ring first.
Ok that might do it.
If not unbolt the inlet nipple where the hose fron the resevoir attaches to the pump
The o-ring will be very hard and shrunken
Does the part on the pump, where the hose attaches look like it can be removed from the pump?
see the inlet joint? o-ring under there
Ok, your car has a different pump on it.
You need to remove the pulley and get a new front seal, that should solve the problem