Maybe a silly idea, but if the snorkel inlet tract (Safari or otherwise) was not watertight it would make sense that it isnt airtight either.
Therefore should be a relatively simple test to block the snorkel upper intake, engine should stall. If it doesn’t, then there’s a leak somewhere?
I’ve got a Safari snorkel (came with the car) appears pretty well sealed through the inner guard through to the air box. Mind you I’ve not been in water deep enough to test for water tightness. [tonguewink]

