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Radiator replacement - best way to tighten olive joints?

Currently replacing some radiators due to springing small leaks. 8mm CH system, so 15mm (half-inch) valves with adaptors and olives.
I've heard that you should hand-tighten the joint over the olive, and then half-turn more with a spanner - correct?
Also, seems to be some dispute about whether to use PTFE tape on olive joints - or maybe jointing paste instead? What's the views folks?

Update 4th Jan 2012
Many thanks to all assistance, reinforces what I thought! Cheers, guys!

Update 8th Jan 2012
Well, took it all apart and reassembled using 10-12 turns of PTFE where applkicable, and jointing compound on compression joints - and it all works without a single leak!
Thanks to all for their invaluable assistance, I now know how to ensure leak-free raqdiator replacements for the future!

6 Answers from MyBuilder Plumbers

Best Answer

you should only use PTFE tape where the thread makes the seal


Answered 3rd Jan 2012

The tightening of the joint, as you have be suggested is correct.

In any event, do not over tighten ! !

I have been in the trade over 30 years and my ppinion of the use of P.T.F.E. over olive joints is :

It's a bit / D I Y ! !

Use Boss white / hawk white paste, for potabale water joint, or something similar !!!


Adrian Hagger


Answered 3rd Jan 2012

Hi Alan,

I would use hawk white joint compound on the actual olives and inside the radiator valve, check out you tube ( normally diy advice on there )

With the screwed tails going into the rad use the PTFE.

Many Thanks.

James Eastman
James Gas Services



Answered 3rd Jan 2012

use jointing paste


Answered 3rd Jan 2012

Hi,use ptfe tape on threads of fittings then tighten up finger tight, then tighten with shift spanner holding the other side with spanner or water pumps give them a good tighten, all should be good, best wishes colin.


Answered 3rd Jan 2012

Yes hand tight and half turn no need for ptfe and definitly no paste,if when you fill the system you have aslight weep on the nut just nip it a touch more.


Answered 3rd Jan 2012

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