Found the final coolant leak the other day - turned out to be the T-piece from the heater feed pipe to the evaporator - a TINY drip which was dripping down on the exhast manifold (hence the morning steam from the exhaust wrap as it heated up!). On removing the T-piece it was obvious one jubilee clip had been overtightened, and squashed the plastic a bit. Also to me the heater pipe seems to be a big bigger than the T-piece and so is overly squashed anyway. I wrapped the ends in PTFE tape and gently tightened again, and the leak has stopped for now.

I want to change the T-piece anyway now and have seen some alloy versions on eBay so I was wondering if a 20mm/16mm/20mm joiner would be the right size?

Thanks all you gurus!

It's better to plumb the reducer in series with the heater matrix than in parallel and using Tees. Very easy on a GEMS but a bit more difficult on a Thor. 20/16/20 will do the job nicely if you leave it in parallel.

I guess it depends on what 'T' piece they have used...

The hoses on the Thor ones at least are about 19mm ID - so a 20-16-20 should give a nice tight fit... Or LPGshop.co.uk have 19-16-19 versions aswell..

I replaced both of mine with metal years ago - feels a lot more sturdy now! Just need to add up the sizes of CT clamp I need now and to swap all of them!

Thanks guys - it's a good old GEMS Rangie - assume the pipes are the same size? It heats up really well in parallel so will probably leave it like that.

AFAIK the pipes are the same size, yes - just different configuration from where they come off the engine and back into the return/bypass lines..

Thanks - will grab a metal T-piece then - something else to do at the weekend!

All done last weekend - I got the 19/16/19 one - pefect fit - no leak! Woohoo