Appreciate the replys. I am convinced the leak is through the pressure cap on the passenger (uk car) side reservoir. The clear pipe consistently steams up. I have removed the pipe from the reservoir and blown compressed air through it with small pieces of paper towel to dry it out. I can replace it and run the car for 30 miles and it's full of condensation again. The cap has been replaced and the temps according to an ODB tool never exceed around 104C but still the level slowly goes down. There is no build on the floor or in the engine base cover or any trace on the radiator etc. Other B48s run at over a bar of coolant pressure but the cap is rated 1 bar and I can't help but wonder if it's marginal. Im tempted to just keep letting it go down until it either stops going down or overheats!

Its a MY25 - picture here

https://tinyurl.com/MY25LEAK

Thanks once again

Rob

Last edited by Rob B; 07/05/25 08:17 PM.