I have used UV dye as my coolant was dropping every few days. I have found a leak at the coolant pipes that go into the bulkhead/heater matrix, I have bought new o rings but have been told these are really tricky to get to re seal. Anyone had any experience on changing the alu pipes to rubber and can tell me where to get the heater matrix adapter and what hoses/fittings I will need? Thanks in advance 

'O' rings are not that hard to fit. You have to have clean and dry surfaces around the pipe. As a retired Instrument technician in Industry we always used  a small amount of silicone grease on the 'O' ring to stop it getting pinched. Sometimes if the pipes cannot be changed,a small amount of sealent can be put on the 'O' ring,to make a  good seal.The 'O' ring suppliers always said sealent was'nt needed,but they had never been in a situation where machine down time  costs money.Not sure if they can be used in your situation.