[glend]

Thanks for the info. I did the job today, while I was flushing and changing coolant. I still marvel at the absolute horrible job that someone did designing that thermostat solution for the CRD. How simple would it have been to have a removable top section and a drop in thermostat, like so many others going back decades. I know that some of the LOST guys came up with an inline thermostat, that sits in the hose path to the radiator; not great but way better than the stock design.
As usual, I did it the hard way, because I wanted to check out the intake hose bend and put some anti-chaff silicon tape on some of the hoses that rub a little. So that meant pulling the air box, the intake and turbo boost hose to the intercooler, and all those little hoses that dance around the thermostat and viscous heater. All good.

Note about that intake hose, from the air box neck to the turbo inlet: if your still running oil mist and blowby gases from the crank case ventilation puck into the inlet hose (an original pollution control design), then there is a good chance that oil will degrade the inlet hose over time. The inlet hose has been known to crack down at the 90 degree bend where it goes into the turbo. So performance issues result, the engine sucking in unfiltered air through the crack, and pushing recycled crankcase mist onto the intercooler where it pools and eventually shoots oil into ths engine intake manifold through the EGR flow control valve where it mixes with the recycled exhaust soot and produces CRD mud which coats the inside of the intake passages degrading performance over time; little stuff like that, so you can see it is important. A Provent prevents this problem, and others, by taking the blow-by crankcase gases through a filter and then the oil is separated out for collection, and the gases can be returned to the intake, or or just vented to atmo (which is what I have always done).