My 41 flathead plym p12 special deluxe overheated and overflowed out of radiator at idle today after 15 minutes. I Fill 2 inches below cap line .. Temp gauge maxed out than stuck at high end.... is there a fix or did I break it. Any experience on this. Temp should run between 160 to 180 I have read. 50/50 coolant mix non pressure cap thermostat 160 or 180 I have a new pump and a flushed system...running too lean possible....altitude is 5000 asl in Colorado.??Thanks if anyone can help... My granpappy passed and I lost the brains of the old school mechanic.