If it isnt meshed correctly and there’s reduced tension, then the tensioner indicator will not be in the correct position ….this would show up when the engine is turned over by spanner….I hope it's just the angle of the photo, that waterpump doesn't look meshed to me - if it isn't. it'll sort itself out but there will be reduced tension...
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Handy to know as my mate has an Impreza lump in his T25 VW van...Even though it looks hard it's one of the easiest to do, once the crank pulley is off.