On changing the oil ready for lift out,I noticed a slight seepage of oil from the oil cooler. This is a plate type mounted on the side of the engine. There are a feed and return pipes that go into the cooler at each side and one is seeping oil.I am led to beleive that you need to remove the cooler to change the O-ring.I have a w/shop manual but unfortunately its for the earlier model which is an aluminium cooler, mine is pressed metal.Anyone had experience of this type and can offer any advice would be appreciated.