300tdi oil pipe coupling

Hi guy's,
Having a right drama with my oil pipe coupling,where the oil pipe goes into the coupling which is attached to a sump type container,

i've just changed the Oil seal, which is the reccomended one, but its still ****ing out oil,

i'm looking at getting a new coupling and metal washer, that bolts onto sump, just incase its u/s and not allowing the nut on the cooler pipe to allow a full fit.

Where does the oil come from which runs through these pipes?
i know they go from the radiator, and through the engine, then to this sump / cooler.
has anyone had these problems before?

Thanks for any help

Bemmy

oil cooler pipes on a 300 tdi run from rad side to oil filter housing ,cooler pipes are prone to leak where rubber hose is crimped to steel ,not expensive to buy new

James,
Thanks for your speedy reply, the leak is where the pipe connects (via a male & Female screw type coupling) onto the filter housing.
Where does this oil come from james is it engine oil?

Many thanks

Bemmy

yes unions are available but may just need nipping up 24mm or 15/16 spanner iirc

James,
Cheers will give that a go during week.

Bemmy