Engine oil cooler removal refit engine in situ

[carreraplanes]

Hi,

I've traced an oil leak to my engine oil cooler. I think it is either the 'O' ring oil seals where the cooler mates to the crankcases or a leak in the matrix of the cooler itself. It looks as if it could be removed without removing the engine (after draining the oil). Is that so? The worst part to me looks like installing the seals when refitting the cooler. It appears that you cannot reach them but their positioning is crucial so as not to repeat the problem. Any thoughts?