[RedP85]

In a recycler (pick & pull, j/y, whatever you call it), or used in the Wanted section here, or other fb groups.
These parts are no longer available at the dealer.
As stated by gamble above, seems also to be missing the fan (item 16361)
itself that normally mount on the front of the assembly above, unless you have an aftermarket electric fan to cool the radiator.

 

[RedP85]

No it's not common.
If the water pump seize, the straps will slip on the the pullies, and rupture from wear before the steel pullies shows any sign of wear.
By the way, from your pic of 2 spare parts above, the left part is a part if that assembly in front if the water pump. The right side part is the bender/idler of the timing belt, behind the front engine cover.

 

[RedP85]

that is the pump for our engine. it includes the sealing gasket, and the 4 studs needed to mount the pullies. These sems to have shreaded from your intial pic.
You still need the other parts of the pullies.
Since you have an electrical fan, you don't need the "coupling" item 16210 above, but need to make sure the nuts on the studs are secure on the pullies if you don't have one. The center bump in the studs might prevent the nuts to go in enough to properly clamp the pullies. You could use 2-3 washers to replace the missing thickness from the "coupling" flange.

 

[RedP85]

MK2 TSRM On-Line

Or pdf download: here

 

[RedP85]

I've posted it in various locations, numerous times.

 

[RedP85]

First, take good note of where nuts and bolts goes. They are not all same lenghts. There is a diagram just for that.
Use same coolant color as what was there. Green, Blue, or Red with proper mixture.
To fill and burp, having car ramps helps : have the front higher, leave rad cap out, pump the lower rad hose to pump some air out. Start car. Bubbles should come out. Run until car warms-up, so thermostat open and really bleed the engine. Top rad as nessesary.

 

[RedP85]

Heat to max or min really has no effect. As as soon they valve by the wiper motor opens (at 30degC) it fully circulate coolant in the heater core. What change the temp inside is the blending flap.
But it is still a good practice for any car.