I am still getting gunk in the expansion tank even after a full coolant flush and change. I was going to see how it goes, but I think it may be time for a new oil cooler even after 65,000 miles only on the car.

Where would be the best place to purchase one and what sort of price should I be looking to pay?

Around the £120 mark from VX
http://www.omegaowners.com/forum/YaBB.pl?num=1211220529

DTC wrote on 17. May 2011 at 08:52:

I am still getting gunk in the expansion tank even after a full coolant flush and change. I was going to see how it goes, but I think it may be time for a new oil cooler even after 65,000 miles only on the car. Where would be the best place to purchase one and what sort of price should I be looking to pay?

Its got nothing to do with the mileage, its more about how well the cooling system has been looked after

ask on here i got one which was good