After driving around with the bus dripping and spraying oil I finally decided to find the leak. As I did not have a spare bellhousing I dropped the engine and removed the fanshroud. Then I reinstalled the engine in t4 style without fanshroud and cleaned up the top of the block. Wired up a hotwire setup started the engine and revved it a few times until things started getting hot without a fan. Oil started appearing at the front of the oil cooler apparently from the seal to the engine block. So I pulled the engine again and removed the cooler. Using brake cleaner it showed me a crack on the cylinder block basically the front bolt on the cooler is pulling a bit of the block away from the main metal. Did not need more than hand pressure to make the crack move. And you can see the crack going half way round the front oil bore going down from the cooler stand as well. I have a bodge in mind . It probably wont work.... And its not totally JB weld.. But I can almost live with the full leak so anything that reduces the leak will help. Then its off to talk to nice engine people. The leaky engine has new heads and valves so probably replacing just the case will work.
Well done for persevering until you found it. @Joker has a case he's selling. Looks in good nick as well from his photographs
I have fitted the bodge and I dont know if it really works yet - but the bus went up to 70mph 105 degrees oil temp this afternoon after I put it all back and drove it on the motorway to go to Halfords to get some gearbox oil. So far not much sign of oil leaks but in the past when all I have managed is oil cooler seal replacement and cleaning the engine , it has taken about 40 miles to revert to having a drop of oil hanging off every downward pointing corner of the engine when the bus is parked after a motorway run. The bodge is a 10mm long piece of 15mm copper pipe split and trimmed down to 12mm diameter, which is the diameter of the oilway towards the front of the engine where the crack is. The oilway was thoroughly degreased with carburettor cleaner, then the bore of the tube and the copper pipe were both coated in JB Weld. Then the pipe was driven carefully down the oil gallery. It stopped at the 10mm depth because there was a step in the bore at that point - where it switched from machined to rough casting. I used copper because it was the material I had in my garage with the closest match (16x10-6 per degree C) to the thermal expansion of AS41 (24x10-6 per degree C) . The best would have been tin, which has the same thermal expansion as AS41. If the bodge works for a while it will buy time to consider my options . If it doesnt work or only slows down the leak, I have already driven the bus about 24000 miles with the crack and leak so I expect I can carry on..
