Surely IFR flight is assumed to include icing conditions - so this is clearly a no-go item then? Apart from which it strikes me as being one heck of an assumption that Wing-Body Overheat is the entire story - how do you know there is not a great deal more to the problem until the engineers have checked it? Plus - you're willing to launch on the cer taintythat there are no icing conditions en route or during any possible diversion (unless it's a very short VFR flight you simply cannot) you'll be able to 100% guarantee avoiding them? I think departing with such a significant defect would be highly questionable and probably not legal.