95 trooper overheats but replaced thermostat,radiator,cap,hoses.

My first guess would be air in the cooling system. For some reason liquid coolant is not flowing thru the engine.
As the engine warms up, the heater hoses should get hot and then the radiator hoses. If you take the thermostat out, you should be able to run the engine and see coolant flowing in the radiator, depending on the make and model.

I have the same model, and had the same problem 2 years ago- random overheats. Problem turned out to be the thermostat installed upside down. The thermostat should be fitted so the operating part with the spring goes up into the engine block. A similar problem I have now is overheats and coolant loss out the expansion tank overflow, specially during wide open throttle driving. Also bubbles in the radiator. Seriously suspect head gasket failure.

replace thermostat.then bleed coolant system, this is how you do it.fill the cooling coolant system with 50 / 50 dexcool and water to raise boiling point,straight water will evaporate boil away cause engine to overheat catch fire thats why you need 50 / 50 mixture antifreeze and water.to bleed coolant system first fill coolant system until coolant stay at the full cold mark on the the coolant overflow jug,then you start engine allow it to idle,place the heater and ac control in any ac setting except max and the temperature control to the highest setting,run engine until lower hose to water pump is hot. with the engine hot run the engine speed up to 3000 rpm and allow it return to idle, repeat this 5 times. slowly open the bleed valve on the thermostat housing or look for bleed valve at the water pump heater hose.open bleed valve for 15 seconds to expel any trapped air.then top off the coolant as necessary,and when top radiator hose hot thermostat open up.keep adding cooling to overflow until coolant level stop at full cold mark dont over fill coolant.if engine seem like overheating while looking at cooling gauge turn off engine wait a while until cool off add more coolant until coolant level stay stable and dont drop any.when open radiator overflow cap use large rag over the radiator cap to keep from getting scald open radiator cap a little at a time but dont open radiator cap until engine cool down first.replace the radiator overflow cap, thermostat,and engine coolant temperature sensor and check the cooling fans fuses and relays see what happens.

I might need a little more information to accurately diagnose situation but I always like to start with the thermostat.(touch top radiator hose if it is cool with temp reading high its probably thermostat) This device is supposed to open up when the engine reaches operating temp. to allow coolant to flow. If it is stuck it could easily cause the overheating condition you are experiencing. Some more info such as does it only overheat when sitting still or will it overheat when moving down the road. If only when sitting still I would suggest a problem with the cooling fan. If it is a gradual increase while driving based off the age of the vehicle I might suspect a clogged radiator. If this dont help try telling me more about it and I will be happy to provide more insight.

ENGINE NOT GOING TO START IF GET TOO HOT FIRST THING I WOULD REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP THEN ADD COOLANT UNTIL COOLANT LEVEL CORRECT THATS WHEN THERMOSTAT OPEN UP AND TOP HOSE HOT.CHECK FOR LEAKING RADIATOR HOSES CHECK TOP RADIATOR HOSE CHECK BOTTOM RADIATOR HOSE.CHECK FOR LEAKS AROUND THE RADIATOR LOOK DOWN BELOW COOLANTS FANS CHECK FOR LEAKS AT RADIATOR CORES OR LEAKS AT THE RADIATOR PLASTIC SIDE CONTAINERS. CHECK FOR LEAKS AT WATER PUMP WEEP HOLE AND CHECK FOR LEAKS AT THE HEATER HOSES AROUND ENGINE BLOCK TO THE HEATER CORE HOSES. THERE IS A REASON CAR OVERHEAT.IF CAR OVERHEAT WHILE DRIVING YOU HAVE FAULTY THERMOSTAT OR LEAKING OUT COOLANT OR BLOWN HEAD GASKET.IF ENGINE OVER HEAT WHILE SITTING DURING A LONG IDLING PERIOD.YOU COULD HAVE FAULTY COOLANT TEMPERATURE SENSOR OR FAULTY COOLING FAN FUSE OR RELAY.HOT WIRE COOLANT TO SEE IF IT RUNS IF NO REPLACE FAN MOTOR. IF YES FAN MOTOR COULD HAVE FAULTY WIRE OR PCM FAILURE. CHECK ENGINE CRANKCASE IF OIL LOOKS LIKE MILK SHAKE ENGINE HEAD GASKET LEAKING.

CAUTION
If the radiator is filled to the top with coolant and the engine is run without the radiator cap in place, the coolant will expand and spill over as the engine warms up.

• Drain some coolant into a clean container until the coolant level is below the thermostat housing.
• Remove the upper radiator hose connection from the thermostat housing.
• Loosen the housing bolts and remove the housing.
• Remove the gasket and scrape it carefully from the surface of the housing and the mounting surface on the engine. If the gasket remains on either of the surfaces, there will probably bea coolant leak after reassembly. Some engines use a rubber O-ring to seal a thermostat housing.
• Compare the size of the thermostat to the old one. They are of different sizes, types, and temperature ratings.
• The temperature rating is stamped on the sensing bulb on the bottom of the thermostat. The temperature bulb faces the block.
• When replacing a thermostat, be sure that the thermostat fits into the groove in the block or outlet housing. If the thermostat is installed upside down, the engine will overheat.
• Install the gasket.
• Reinstall the thermostat housing. Refill the system and run the engine or pressure test to check for leaks.
• When the engine has reached operating temperature make sure the thermostat opens.
• You should be able to see coolant circulating within the radiator.
• Another way of checking thermostat operation is to feel the top of the radiator hose or use a thermometer or multimeter with a temperature probe to confirm that the coolant is warming up.
• If the engine is overheating, but the top hose is still cool to the touch, the thermostat is stuck closed and must be replaced.

NOTE When a paper gasket is used and the recess is in the thermostat housing, it is a good practice to position the thermostat into the recess and glue the gasket to hold it in place. If it falls out of its groove during installation, the outlet housing can be cracked or a coolant leak will result. Before tightening the water outlet housing, try to rock it back and forth to be sure it is flush. Housings are often cracked during this step.

head gasket is blown

Your radiator efficiency has been reduced by (what is called) blossoming. Blossoming is electrolytic growth of crystals inside radiator duct passages. This typically occurs in the older Troops as gradual overheating probs cause the vehicle to run low on coolant, then water is being used to top off system repeatedly, acid levels in cooling system rise as the coolant protectants degrade and the inside of the radiator ducts 'blossom' with small crystalline growths that reduce the radiators flow and ability to cool the engine. Flushing and blowing out the radiator are temporary fixes. Replacing the radiator is the permanent fix. You did the right thing by replacing the water pump, tstat and radiator cap. An old, original water pump usually fails soon after the radiator is replaced. New Trooper radiators are fairly cheap, $85+. The replacement can be done by any backyard mechanic or DIYer in under and hour. You know the typical warnings about the toxicity of antifreeze and the deadly affects on pets who drink improperly disposed coolant. Good luck to you. It's an easy remove and replace. Your Trooper will thank you with many cool running miles. -Geoff

First off, while the car is cold, remove the radiator cap, and start the car. Let it warm up, and make sure the fan kicks on, and make sure the thermostat opens up. There is no danger in doing this. The cap is off, so no pressure can build in the radiator or burst out. That only happens when you remove the cap when the car is hot.You will see the coolant flow throught the radiator if the stat opens. If the fan doesn't come on, I would say you need a fan. If the fan comes on, and the coolant DOES NOT flow, you may need a water pump, or by chance, your new thermostat is bad. Also, without flow, that could indicate the radiator is bad. Flushes are good, but not always right. If you wait again til the car is cold, take the cap off the radiator, and get a bucket to drain the coolant in by taking the bottom hose off. Stick a water hose in the top and make sure water comes out of your bottom port. Hope it all goes well.

COULD BE COOLANT SENSOR,HEAD GASKET,CHECK THE TIMING,THE PROPER MIXTURE OF COOLANT,WATER PUMP.DID YOU HAVE IT CHECKED OUT?ANY LEAKS?HEAT WORK WITH FAN?