I’m not familiar with the JTS but I’ve seen this on another car. It had positive crankcase ventilation, as I believe the JTS does. When the control valve failed too much vacuum was applied to the crankcase and a whistle developed from the oil filler cap as air was pulled past it. (It might be designed to do this to warn you of the valve failure.)When ticking over the engine makes a strange noise like someone trying to play a recorder. If I remove the dip stick or oil filler car the noise stops. It must be related to crankcase pressure. It's not coming from the PCV valve. Any ideas???