 Blown Head Gasket?
Just went through similar problems with my daughter's 1994 Mazda Protege with automatic transmission and 1.8 litre dohc engine. We constructed a jumper wire [through a 10 amp fuze] and plugged it into the main paddles under the fan motor relay, in the fuze box. Radiator cooling fan came on, so we knew the cooling fan wasn't the problem. We then installed a new relay and presto: problem solved ($14.99 part from AutoZone).
If you are getting hot coolant blowing back into the expansion tank, it is possible that you have blown a head gasket. Is the liquid in the catch tank green like antifreeze, or is it now frothy and cream-colored? Does the liquid in the catch tank smell like antifreeze, or does it now smell kinda like gasoline or exhause fumes? If it is frothy and cream-colored and smells like something other than antifreeze, the head gasket may be the problem. There are a couple of compression tests you can run. First, and simplest, is to get a pair of them big plastic pliers, and -- with the engine running -- pull one spark plug wire at time, paying attention to how much of an RPM drop you get when you pull the wire off the spark plug. If you get no RPM drop, or less of an RPM drop than on the other three cylinders, you could be in the neighborhood of where the head gasket is blown. A more sophisticated test would be with a compression guage, which you mey be able to borrow from an auto parts store. For this test, be sure to first remove the high tension wire which runs from the coil to the distributor. Next, remove all four spark plugs. You can then screw your compression gague into each spark plug hole, one at a time, then crank the engine, repeat for next cylinder, etc. When finished, compare psi readings for all four holes. If one of them is like non-existant or way lower than the other three, then the head gasket could be blown in the neighborhood of this cylinder. I hope a blown head gasket is not your problem, because if it is, you will have to pull the head, take it to a machine shop where they can check for cracks (dye and/or magnaflux), and check to see if the head is now warped. In any event, you would probably want to have them mill the head, to make sure it is perfectly flat, else more blown head gaskets. I hope this is not your problem, but when you get coolant blowing out of your expansion tank, it generally means that pressure from a piston is the reason, and the cause is a blown head gasket. Because it is somewhat expensive to fix, don't rely on what you've just read. Get a second opinion. And a third and a fourth.
PS: My 1998 Contour LX runs just fine, and its been hotter than hell in Houston lately. | 
