it is worth checking the dipstick rubber tube --- not what's in your picture but in that area --- there were some around that weren't 'viton' and deteriorated quickly
looks like this
https://www.justkampers.com.au/catalog/p...gKhPfD_BwE
looks like this
https://www.justkampers.com.au/catalog/p...gKhPfD_BwE