engine oil cooler

Hi guys,
I changed my oil cooler sometime ago and after starting the car the engine oil was sprayed out from one of the bolts holding the oil cooler; not the housing in place. the repair kit I bought had 2 green rubber 'things that were to be placed on top of the bolt. that is exactly the place where the oil leaks. those 2 green rings are much larger than the head of the bolt, is this normal?
I replaced the leaking green ring with one of the used one; drove the car for approx. two weeks and lost engine oil again

What model Disco is this? If it's a TD 5 the o'rings go inside the cover to seal the matrix to it.

it's a second gen model, year 2000. I mean the 2 green o rings. when I replaced the faulty one I saw that the green o rings where placed on the outside.

Your green nitrile rubber O rings should be under the banjo bolts head and when installed and the bolt tightened shouldn't be seen, as for oversized have you tried fitting them into recess of the main housing first, if as you say they "are much larger than the head of the bolt" then they maybe incorrectly supplied with the cooler kit.

o rings should be fitted in a recess bolt head needs the dowty washer

Hi guys, brought the car back to the dealer to get the engine oil leakage fixed which they did but only lasted a few days. Whilst driving all the engine oil lost again; brought it back to the dealer and they said that it is due to a crack in the oil filter adapter where the oil filter screws in. I very much suspect that since the first time they said it was the gasket which they replaced. I am guessing they did not put the gasket back in properly and thus calling on another part to hide their mistake. Does anyone know of the oil filter adapter getting a crack?