Angled radiator valve 10mm and stem elbow 10mm

[mrbzu]

Hi,
My radiator had a leak on stem elbow which is over 20 years old. To stop leak I cut the pipe and put push fit stopper.

i bought 10mm angled radiator valve with 10mm stem elbow. If I put olive thatcomes with valve on stem elbow and tight the valve,the elbow is very loose and comes out of valve. I am not sure what I am doing wrong here. Can you please help. ? Surely all are 10mm pipes, valve and elbow

Do copper olive is the solution not sure?

 

[Aquarius]

Might not be tight enough into valve? Hand tight or spanner tight?

 

[SimonG]

I'd bin the hideous plastic stem elbow and get a chrome one. Lot more aesthetic.