All the info is in this thread but to summarise. I fitted an A/C system 2 years ago. Have had the bus on dyno at Leons after carb rebuild, the A/C compressor takes 5hp rwhp. At Christmas I tow a 400kg trailer and 14 foot SUP board on roof to so expect a lot from the old girl. This thread was about the missing flap and how re-instating it made no difference so I do suspect the internal oil cooler.