(Still) leaking oil cooler union

[Doc007]

The right (as you look at it) oil cooler union whose pipe goes to the top of the triangular dry sump tank still seeps a little when the engine is up to temperature. I've tried removing, cleaning the mating surfaces and threads putting it back together but had no joy.

Any suggestions?

I was thinking of replacing either the oil cooler (£100) or the pipe (£150) but am not sure which is likely to be the problem.

I'm also not whether the OE pipes on the Caterham website would fit my oil MOCAL cooler.

[ScottR400D]

That's quite surprising IMO because there's no pressure in that pipe so it begs the question of how bad the leak would be if it was under pressure. The implication is that it's quite a fault on the fitting somewhere. 

As for changing the cooler or the pipe, if the damage is on one or other mating face then that's the one to change. 

If it's on both they'd both need changing. 

If you can't see any damage then it's hard to know. 

I wonder if something like this is available over here?

It appears that they are, earls.co.uk

[ScottR400D]

Wasn't it the other one that was leaking earlier?

[Doc007]

Yes, Scott. It was!

But removing/cleaning/reattaching seemed to do the job on the LEFT.

[ScottR400D]

It might be worth trying the clean/reseat again on the RH one