Since the weather turned wintery it has been difficult to get outside and figure out why the RB is still mixing coolant and oil.
Thankfully, last weekend a chance finally arose as the skies stayed clear, so I got out there and after bolting the turbo back on (so that none of the coolant or oil lines were left open!) I did a pressure test on the engine.
A pressure test is pretty much as it states, you pressurise the cooling system of your engine and if the pressure stays constant you’re more than likely okay (or looking in the wrong place), but if you see pressure loss you have a leak somewhere.
The coolant pressure test kit comes with a variety of different radiator caps and fittings as well as a hand pump, I found the correct sized cap for my radiator, fitted it, connected the pump and then started pumping to the required pressure.
I left everything for long enough to make a brew and when I came back, sure enough, I had lost pressure.
After leaving it a bit longer it continued to lose pressure after double-checking all of the lines to make sure there were no leaks.
This confirmed my suspicion that the head gasket was probably due for replacing (or worse that there may be a crack in the head somewhere.)