[Wg123]

On the Saturn SW2 the expansion tank is pressurized with the system and only has a fill cap on the overflow. The over flow tank is pressurized with a pressure release value for excess. I did think the same, that when I added the coolant when it was cold that it could have expanded when hot and just over flowed but the first time it was steaming over and making boiling sounds. This is all at 1/2 on the dash gauge in which I never have seen my gauge that high in the prior 8 years I owned the car, not even in summer heat sitting at an idle for hours...

Ever heard of a water pump just working poorly without a leak or noise?

Thanks greatly for you help!!!