I'm not familiar with Lister diesels, does the dipstick 'live' in the dipstick port or do you put it in only to take the oil level measurement? could it be throwing oil out of the dipstick hole if it is not sealed? I had a similar problem with a Yanmar 2GM20
which Installed to replace a 1GM10
, I noted that the dipstick was a lot shorter on the 2GM
than on the 1GM (lower down the block) but didn't connect the dots when i then installed an oil level sight gauge which originally just had a tube which just sat in the dipstick hole without sealing it. Had worked fine on the 1GM but threw oil everywhere on the 2GM
due to the lower position. Solved
the problem by removing the sealing 'bung' from an old Yanmar
dipstick and forcing it over the tube, allowing it to be sealed into the hole.