99 Ford Explorer won't turn over

See if your crank case is full of coolant by draining the oil pan and pull out spark plugs to see if coolant is in on top of the pistons by adding some oil back in oil pan and draining the radiator first if oil pan had coolant in it and then turn engine over by hand or short burst by starter, you may be hydro-locked and continuing to try to start it could lead to broken/bent rods or pistons but by doing that above will get it out so you can repair it. If so you may just need intake or head gaskets and new thermostat and radiator cleaned and check fans/relays/ fuses. Get codes read to see if anything is subject.

Just purchased a new re-manufactured 4.0 OHV engine from Ford with a 100,000 mile warranty. Cost of engine is 2600 bucks, not including labor. It's complete including intake manifold, spark plugs, water pump, and oil. New Motorcraft injectors are about 40 bucks each. Get an estimate to repair the current engine then weigh the difference in price compared to a new engine. Repairs to engines are not cheap. If things like heads have to come off or heads rebuilt, if probably to invest in an engine

This is the best idea, because doing the work yourself or sending it to a shop for the work to get done to the engine does not mean its fixed and it can mean money spent and no good results but re-manufactured with warranty means after the install it will make it 100k even if they have to replace it ten times. Keep all records, labour too. It would be better to let a shop do the install so you have installation records to satisfy the warranty if need be in the future.