audifan
A2OC Donor
If you are careful insert an extension bar straight through the ports that had the upper two rubber pipes. That may give you a bit more leverage and something to grip hold of. There is a chance the housing is brittle due to age and may break coming off, spray some hot water onto the area at the back where it fits to the block, then wiggle each end of the extension. If still refusing to budge then even more carefully apply a lever onto the ends of the extension bar either alternating on the ends or both together. I think the housing or seal has bonded itself to the block due to oil or diesel. It does look like it is not secured to the block as only the two points hold it on.