How to bleed a system without a reservoir?

[Evilmethod666]

So my current setup is fairly standard water blocks for CPU/GPU, 2 rads and a pump/reservoir combo. If i want to do any maintenance i can drain the system then refill via the inlet port on the Pump/Res and leave one of the top ports on the res open to bleed all the air out the system nice and simple!

I'm looking to downsize to a Meshify C and will no longer have room for my current pump/res combo so was going to mount a D5 with top just under the graphics card. The pump top has 2 inlets and 2 outlets but I'm not sure how i will bleed the system as i can't leave one of the ports open to vent any air in the system with the pump running?

My rads have the standard two ports

 

[Undesirable]

You need something like an inlet port using a t-fitting and tubing sticking out above the highest point of the loop, which can be closed by bunging up.

 

[LuckyBenski]

You need something like an inlet port using a t-fitting and tubing sticking out above the highest point of the loop, which can be closed by bunging up.

This. I'd recommend getting a ball valve fitting too, incredibly handy even for the few occasions you'll be opening and closing the loop. There's always more time spent filling or draining than you expect!

It would alternatively have been useful to have a radiator with extra ports as your highest point, my 360mm rad has extra ports I open to bleed air from.

Remember that you need two openings to fill/drain, one for fluid/air in and one for air/fluid out.