Just changed the water pump and now the engine is getting hot with coolant in it.

you have overheated the engine maybe thermostat or water pump fault

Sounds like your coolant is not circulating for some reason. Typically it's the thermostat that blocks the flow. If turning on the heater inside helps the car not overheat then your coolant is not flowing. Other issues can be a water pump that isn't working, air in the system that has not been bleed out, engine head broken (blocked).

Yes, you are running hot from leaking all your coolant out. No one can tell you where it is leaking without looking at it. Could be a hose leaking, the radiator, a bad head gasket or intake gasket, the water pump...if coolant is leaking from the front of the engine, that could be the water pump or radiator hose or a water pump gasket. Pretty common for the water pump to leak when it is worn out, that's how you know when to change it.

When you fill the radiator and overflow tank back up to full, does the engine still run hot? If it does, I would not advise running it-have a shop diagnose it before more serious damage occurs. Head gasket repairs can get very expensive-that is the danger you are facing, and if the head gasket has already gone bad from overheating, continued running of the engine can cause you to have to replace the engine. Overheating is a major cause of early engine failure.

Try to determine where the leak is, from where it drips off the engine. The coolant constantly circulates from the engine to the radiator and back into the engine. The heater hoses circulate coolant from the engine to the heater core in the heater case and back into the engine. Besides the overflow tank, these are the only places coolant would be on the car. The engine can leak coolant from a lot of places, but if leaking to the outside, you should be able to spot where it is coming from. Good luck.

could be water pump. Check weep hole on water pump body to see if its dripping. if it is, then your pump seals are bad. Now, if coolant is leaking from engine, it could be from water jackets or engine drain plug. this all depends on where you're seeing coolant leaking from. Also, if it's not registering as hot, you might want to look at the coolant temperature sensor.

REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.IF CAR OVER HEATING WHILE IN MOTION.MORE LIKELY ITS THE THERMOSTAT,LOW COOLANT IN RADIATOR OR COOLANT SYSTEM,BAD WATER PUMP,WATER PUMP WEEP HOLE IS LEAKING, WATER PUMP NEEDS REPLACING.CHECK ENGINE OIL,IF OIL LOOKS LIKE MILK SHAKE YOU HAVE LEAKING HEAD GASKET.IF CAR IN PARK AND OVER HEATS WHILE IN A LONG TRAFFIC LINE OR.BANK DRIVE THROUGH COOLANT FAN NOT TURNING ON, BECAUSE THE ENGINE COOLANT TEMPERATURE SENSOR FAULTY.CODE SCAN CAR FOR FAULTY COOLANT FAN RELAY OR FAULTY PCM. CHECK COOLANT FAN FUSE, AND HOT WIRE THE COOLANT FAN TO MAKE SURE ITS WORKING.IF COOLANT FAN DONT WORK WHEN HOT WIRED. COOLANT FAN NEEDS REPLACING. REPLACE BOTH RADIATOR HOSES, REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.BUY NEW COOLANT ADD 50/50 WATER AND COOLANT.IF ENGINE OIL HAS ANTIFREEZE IN IT.REPLACE ENGINE OIL AND OIL FILTER TO KEEP FROM LOCKING UP THE ENGINE.GET CAR FIX.DONT KEEP DRIVING IF IT KEEP OVER HEATING,ENGINE DAMAGE WILL OCCUR.I HOPE INFORMATION I GAVE YOU WILL FIX PROBLEM.PROBLEM COULD BE LEAKING RADIATOR HOSES BUT CHANGE THERMOSTAT THATS FIRST THING I WOULD CHANGE BECAUSE IF IT CLOSED, ENGINE WILL OVER HEAT AND CRACK CYLINDER HEAD OR CRACK PISTON, COOLANT NEED TO CIRCULATE THROUGH THE ENGINE TO TAKE AWAY THE HEAT FROM ENGINE.

One of two things: 1)Heater core may be plugged - on most vehicles you can switch the heater hoses around to reverse the flow of water to try to remove the blockage. This will be a temporary fix however because the foreign material will be in the coolant system and will eventually plug the core again. If you try this and it helps I would suggest flushing the coolant system to remove any loose material. 2)Failed water pump - Sometimes the impeller on the water pump gets corroded to the point where it will not move the coolant correctly. The solution for this is to change the pump. You can do some troubleshooting buy A)draining enough coolant from the system to drop the level below the upper of the two heater hoses B)remove the upper heater hose on the engine end and position the open end higher than the engine, allow coolant to drain to the point where it naturally stops C)Have a friend start the vehicle breifly and see if coolant flows from either the hose or the fittting it was connected to. If coolant flows from the hose, the core is not plugged. If coolant flows from the fitting, the water pump is working. If coolant doesn't flow at all, try switching the ends on the core if possible and repeat test. If the coolant still doesn't flow, you probably need a water pump.

Mitsubishi Galant/Mirage/Diamante 1990-2000
Water Pump - REMOVAL & INSTALLATION

1.5L and 1.8L Engine





Fig. Water pump and related components-Mirage with 1.5L (4G15) engine



Fig. Water pump and related components-Mirage with 1.8L (4G93) engines

1. Disconnect the negative battery cable.
2. Drain the cooling system.
   

CAUTION Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Remove the engine undercover.
2. Disconnect the clamp bolt from the power steering hose.
3. Remove the engine drive belts.
4. Support the engine with the appropriate equipment and remove the engine mount bracket.
5. Remove the timing belt. Refer to the timing belt procedure in this section.
6. Remove the power steering pump bracket.
7. Remove the alternator brace.
   

NOTE The water pump mounting bolts are different in length, note their positioning for reassembly.

1. Remove the water pump, gasket and O-ring where the water inlet pipe(s) joins the pump.
   

To install:

1. Thoroughly clean both gasket surfaces of the water pump and block.
2. For 1.5L engines, install a new O-ring into the groove on the front end of the water inlet pipe. Do not apply oils or grease to the O-ring. Wet the O-ring with water only.
3. For 1.8L engines, apply a 0.09-0.12 in. (2.5-3.0mm) continuous bead of sealant to water pump and install the pump assembly. Install the water pump within 15 minutes of the application of the sealant. Wait 1 hour after installation of the water pump to refill the cooling system or start the engine.
4. Install the gasket and pump assembly and tighten the bolts to 17 ft. lbs. (24 Nm). Use care when aligning the water pump with the water inlet pipe.
5. Install the remaining components in the reverse order of removal.
6. Fill the system with coolant.
7. Connect the negative battery cable, run the vehicle until the thermostat opens and fill the radiator completely.
8. Once the vehicle has cooled, recheck the coolant level.

1.6L and 2.0L (SOHC and DOHC) Engines



Fig. Water pump mounting-2.0L DOHC engine shown

1. Disconnect the negative battery cable.
2. Drain the engine coolant.
   

CAUTION Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Remove the timing belt. Refer to the timing belt procedure in this section.
2. If necessary, remove the alternator brace from the water pump.
3. If necessary, remove the timing belt rear cover.
4. Remove the water pump mounting bolts.
5. Remove the water pump, gasket and O-ring.
   

To install:

1. Install a new O-ring on the water inlet pipe. Coat the O-ring with water or coolant. Do not allow oil or other grease to contact the O-ring.
2. Use a new gasket and install the water pump to the engine block. Torque the mounting bolts to 8.7-11 ft. lbs. (12-15 Nm). Install the alternator brace on the water pump. Torque the brace pivot bolt to 17 ft. lbs. (24 Nm).
3. If removed, install the timing belt rear cover.
4. Install the timing belt. Refer to the timing belt procedure in this section.
5. Install the remaining components.
6. Refill the engine with coolant.
7. Connect the negative battery cable, start the engine and check for leaks.

I really hope this help (remember rated this help).

could be waterpump?
i was going to say rad fan,but if so heater would be hot.
lack of coolant will make heater core to blow cold,if engine heats up with full coolant,usually means poor or no circulation.
water pump?
run engine with full coolant,at operating temp.with rad cap off and look in rad cap hole and see if there is movement of water inside rad.
[rad fan will not come on if water is not circulating through rad water pump?]

Did you change you ECT (ENGINE COOLANT TEMPERATURE SCENSOR) ?

if you see the water leaking form the front side of the engine usually from the water pump since the pump is not running you also wont get heat, bit when you pressurise the sys you are forcing the hot water into the core and you have heat, it is the water pump.