I have had a good look at it and have worked a solution. To cut a long story short I had the engine reconditioned and returned last week so I thought I would check it over. Of course a few things were not fitted properly at their workshop.
Got underneath last night, removed tin under cylinder 1/2 to find air flow control thermostat wasn't connected to the rod. Fan shroud internal flaps in this instance are open and therefore cable to oil bath is pulled up opening the butterfly. So I connected the thermostat and this pushed the oil bath cable out to close butterfly. Although I am not sure how the wire is fitted to the clip but I have fitted it anyway, for completeness it would be nice to know how it is actually fitted...my van is totally original ('cept for a few period items fitted by the original owner) and I want to keep it the way the German engineers designed it.
That also means fitting the heat exchangers to their respective cables, refitting the engine bay surround rubbers correctly, refitting the steel fuel pipe bulkhead grommet and further along the pipe the bit of rubber to stop contact wear of the pipe against the fan shroud. Correctly fitting the accelerator cable (only 3/4 fully open!!!). Took it for a spin around the hills and it appears to all work, engine bay feels cooler now. Come the cold weather all these measures should in theory operate as the engineers intended.
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