Don't quite understand your question but if you have oil in the water failure of the cooler is quite possible as is a leaking head gasket. The cooler is usually screwed to the block under the filter.

hi

I may have a gas failure on the oil cooler-any tips on cost to replace? Also notice coolant has gone brown.

chrs

me neither. Gas failure?

If you have a failure of a water to oil oil cooler, then transfer would be oil to water as oil pressure is higher. So a dirty, oily appearance to the coolant would support this.

I'd suggest avoiding a secondhand cooler as you can't know it's not as bad as the one you're taking off (it may have come from a car with infrequent oil and coolant changes).

OE is likely to be pricey (it's VW afterall). You could consider bypassing the original and fitting an aftermarket cooler (air to oil) from a motorsport outlet. You'll have to cost it out for value.