[RM955I]

You're probably right - that crossed my mind too.

There's still oil coming through and the cap has been on and off numerous times as I either syringe the top layer of floating oil out: or, I've had the cap off and the expansion tank out a few times and rinsed it with hot water and detergent.

I was due to give it a proper flush using dishwasher tabs (dissolve one, add it to the tank, let the car idle for 30 mins and then cool and drain...repeated 2 or 3 times; then a good rinse. I just didn't get to it as the weather was terrible at the weekend.