I have a 98 expedition and it is using alot of

you obviously have a leak. try running with the radiator cap on 1st click so it doesn't build pressure. If it quits leaking, you probably need a radiator. 1800 radiator seems to have the best prices on quality parts.

i myself had this problem it cud be your thermostat malfunctioning a clogged heater core or a leak in the cooling system or even worse a bad head gasket . does your overflow tank blow out coolant? check your oil look for water if no check your coolant over flow tank does it smell like exhaust? if oil is good and overflow tank smells fine you have eliminated bad head gasket few right.so then you check thermostat make sure its not sticking open or closed .check heater core if you have heat thats good . so best case sinario its the water pump atleast was the case with mine in summer ran water in it but water evaporates quickly as expected but as winter approached i added antifreeze right then and there the water pump started to squeel and leak antifreeze out the weep hole located on the top of water pump i replaced water pump and have not had a problem since hope this helps good luck

Clean the injectors and check spark plugs.

I drained my system out and ran a water nozzle into the coolant jug. this will help get any slime/grime out. They make a coolant cleaner you can use. I rushed plain water through until it came out white. But while I did this i had my engine running to circulate the water at a hot temp to loosen up other grime. leave hose in for 5 min while water is pushed through. go cut car off and let it drain for 2-3 minutes. plug your drain hole and put in Antifreeze not the 50/50. Pour in the whold bottle and rest with water. 1 gallon of antifreeze and fill with water.

It could consist of skipping, engine cutting off or hesitates from starting, idling . Bad gas gives numerous signs, the best way I have found to deal with this is, Buy a octane booster 104, go to the gas station and put a couple of gallons of high premium in to tank to disperse the water in the gas. They also make a liquid to take water out of gas which also goes into the tank.

Get a tin of a good quality Radiator Sealant or a couple of packets of Ce-lit and apply them to the problem

Once you have stopped the leak go back to the stadard mix of Anti Freeze to Water

most likely the heatcore is the problem, The heater core is just a small radiator the uses the water from the engine to heat up your car. it is nice but since it is just a radiator it can become clogged by engine debri. the best method I found is to unhook the two hose going to it and pour water through it first, if it is really slow then that is the problem, the way I fix it is blowing air through it at low psi, and also using a little water. blow lightly back and forth and in no time it should get out all the debri. pour alot of water throught before you hook it up, I did about a gallon.

If the fuel gauge drops off when you are driving then its a sending unit problem that means you have to drop the tank and replace the float and sending unit. This is a common problem for alot of cars because of cheap gas. If you have to drop the tank check the fuel pump canster for dirt because of cheap gas. Replace the fuel pump strainer and fuel pump filter. If the car or truck has about 100,000 miles you might want to change the fuel pump at that time also just to cover your back. If you take it to a shop they will charge you at least $900 to start. But if you do it yourself it will cost you about $200 dollars maybe alittle more.

you have a leak somewhare in the system, i would check the suspinsion air bags on the rear first cause thay dry rot over time and start leaking