Oil cooler leaking at engine block....

[wasp]

Hi all
Has anyone had this problem....heres what happened..
Did oil changes yesterday all went well except when tried to unscrew the oil filter,instead of the oil filter unscrewing off the treaded shaft,the threaded shaft unscrewed from the engine block releasing the oil cooler...So i removed the filter from shaft ,cleaned the matting surface between block and oil cooler,re inserted shaft tru oil cooler and back into block and tightened it up.Then replaced oil filter as normal,and refilled engine with new oil.
Start engine up ,small leak from cooler to engine block.
so took apart again,replaced rubber seal between coller & block,retighted threaded shaft this time with socket n wrench so tighter (cant find any torque settings in haynes comic),road test and yep its still leaking still !!
any ideas?
Dave aka wasp
oh its 406 hdi 1999 110 wiv 255k miles

[plod]

There is the possibility you may have "overtightened" it and distorted the seal thus causing a leak

I had the same problem that the shaft came out when doing my filter, but didn't have a big enough socket 27mm IIRC, but had a 27mm spanner but couldn't get enough purchase on it to do it really tight, and haven't noticed a leak, so maybe that's it?