If anyone is interested, there's a really good step by step instruction guide at Volvospeed for the replacement of the radiator

http://volvospeed.com/Repair/Radiator850turbo.php

I have just replaced my radiator today and I thought I'd extend on these excellent instructions:

1. Remove the two top screws that secure the fan to the shroud and loosen the two bottom screws as well. Tie and secure the fan with a thin used hose so that it doesn't slide down.

Removing the fan this way by pulling it away from the shroud gives about an inch and a half gap to allow the intercooler outlet enough space to clear the fan shroud, so that the intercooler/radiator sandwich can drop down.

2. Secure the retaining clips for all 4 oil lines to the radiator with hose clamps.

3. On Nissens radiators, for RHD cars, if you're importing the radiator from the US (which means the radiator is designed for US model cars), a hole needs to be drilled for the right side bolt that secures the airconditioning radiator to the radiator itself. Best to fit a putty knife in the gap between the plastic edge of the radiator that needs to be drilled through and the oil tank directly below the hole to be drilled. This would prevent damage to the oil tank from an accidental drill through.

4. I have not found the need to replace the gaskets on the oil lines to the radiator but YMMV - be prepared with new gaskets on hand just in case you need to replace them.

5. Only use quality radiators - Nissens or Behr.

I wasted 5 hours last weekend when I installed a defectively designed Taiwan made radiator (Moto Kool brand here in Australia) that had such a small opening in the oil intlet and outlet lines that the engine oil inlet line blew off due to a build up of excessive oil pressure. Oil seeped out from the oil filter as well. It was a major waste of a lot of time time and an almighty mess to clean up.

Do it once, do it right, with the right quality part. Lesson learnt.

I eventually installed a Nissens radiator shipped in from the US (couldn't find one locally) hence point no.3.

6. The 850 T-5 needs 7 litres of coolant. I had to drive around with the low coolant indicator flashing a few times, with the overflow tank cap removed a few times at stops along the drive before I could get all 7 liters put in. There must have been a massive air pocket in the coolant flow path.

7. Removal and replacement of the radiator can take up to 4-5 hours if you're doing this for the first time.

Hope this helps someone with a RHD 850 T-5.