my 2001 Ford Explorer has started overheating but there is no steam or water running out and when I turn the heater on I get slightly warm water what can I do? the temp gauge will go to hot and after a while will drop down then go back up to hot what kind of damage am I doing to my car?

Lots of risk for damage. You probably have a leaking head gasket. The water is going our your tail pipe, the slightly warm ?water? coming out of the heater (warm air maybe) is due to low antifreeze level. Get some antifreeze/water and get the level up to the proper level. You want to avoid overheating, that will add $$$ to the repair bill. Get this to your mechanic and have them take a look.

Overheating will kill your engine. As said, fill it up and never let it get to the red and go to the mechanic straight away. Better yet would be have it towed.

I concur with the advice above to have it towed to a shop for an assessment of what’s causing the overheating. Think positive, it could be a simple fix, like the coolant level is low, thermostat on the fritz, or an air bubble in the cooling system. Or it might not be so simple. But one thing is certain, continuing to drive it in this condition is likely going to be more expensive than the fee for getting the problem properly diagnosed.