So, apparently no-one else has had the problem of the overflow tank going empty? The car doesn't overheat, seems to run fine, no water in the oil, new water pump, new overflow tank. ANY ideas?

 

Gotta get it pressure tested and look for leaks among the cooling system components. Test the cap as well

 

Seems no one in this area has the equipment to test a Volvo, and they don't want to spend the money for the equipment for the small number of Volvos in this area. The cap was replaced with the new overflow tank. My wife says its worse when she does a lot of start and stops. I'm wondering if it could be some type of pressure buildup that is back flowing out when the car is shut off.

 

why would it take special equipment to pressure test a Volvo versus any other car. My indy tech pressure tested my S40 for me, no questions asked (found a leaky thermostat gasket). So the coolant has to go somewhere - Does the HVAC have a sweet smell to it when you first start up (ie sign of a leaky heater core)? Is there any staining or water marks around any of the hoses, on the radiator (coolant could be leaking then boiling off a hot surface before it drips)? Any white smoke (particularly on start up after a warm up or an odd smell to exhaust? (leaky head gasket or turbo seal?). Try feeling around the carpeting for any dampness and do a good look under the hood, particularly around hoses and radiator seams and fins.

 

If it's that bad of a leak, you shouldn't even need a pressure tester. Just a visual inspection should find it. Unless it's getting into the combustion chamber, of course.

 

I agree. A good visual and smell inspection including a direct look at the heater core is called for. If nobody will diagnose it who is physically present, we'll sure not be able to do much for you on the internet.