Hi Guys, Thanks Bruce you're right it's a balanced system, need to check each part. Yes, the cooling fans were out for about an hour, got the new relay & they're ok now. The surge tank has actual cracks in the plastic that are leaking steam, pressure, coolant. Definitely not holding pressure. That's why I was wondering if no pressure alone like leaving the pressure cap off & driving around in hot weather would cause overheating by itself.
Thanks JD, yes, coolant leaking from overflow hose & tank. Tank has bad leak at both hose connects, plastic has failed. Going to test the