the terminator is very small
.

But it is still an awesome movie

I think the thermistor may not be seated properly unless you skipped the "heat tightening" step.

All E3Ds are sold as kits. When in doubt, you *could* ask an experienced user to assemble one for you, but 3D printers have a learning curve as it is. If you have already invested your money into your unit, invest your time in learning the machine. It can seem daunting at times, but it's worth making a mistake here or there to have the knowledge for future reference.
No matter the hotend, it can still clog if not assembled right or being used with improper settings. I have clogged mine a couple of times, but since the E3D is a superior hotend, I was always back to printing in no time.

You can see for yourself by looking at the assembly guide on e3d-v6 webpage.

so in my case look like it wasn't properly assembled.

for ABS and for PLA each time I did change filament type.

maybe the termistor yes, it's kinda very tricky to assemble...

Elmoret is there a way to buy one already assembled?

Heat is likely the issue and not from assembly.

my hot end clog every time it stop or slow extruding (if that make sense...)
I have try both ABS and PLA (I did clean totally the hot end between changing type, acetone, and gas flame and a good blow of compressed hair)

I extrude, then if I stop, I have to retract the filament cut the tip and start again.

The picture is from the filament after a clog, they form very rapidly.