I own 95toyota 4 runner. I need help on.the best process to drain,and refill engine coolant. I thank every body for any tips and advice I recieve.

Fernando, there is little that can be done to the valve as far as service. It exists in an ugly environment and deteriorates. Just replace it.

first do this when engine is cold, i know its obvious but its always good practice when giving advice to be thorough,then remove the rad cap, there will be a drain tap/plug at bottom of rad undo a let coolant drain out, the rad is usually held in place by 4 bolts 2 each side loosen these off then remove top and bottom hosesfrom rad, and depending on fitting type lift rad straight up , if does'nt lift up remove the bolts and lift rad away.install is a reverse top up with COOLANT not plain water run engine once refilled and look for bleed screw(s) on the hoses/engine body to let air out ,if has an electric fan ie turns on and off not running all the time wait for the fan the cut in an turn off engine allow to cool for at least an hour and slowly remove filler cap to check coolant level top up if required repeat until no more coolant needs to be added .Good luck

4 Cylinder Thermostat Removal

1. Drain the coolant by opening the drain cock or removing the lower radiator hose. Remove the lid to speed up process

2. Remove the throttle body cover on turbo cars

3. Remove the bypass hose and the pressure pipe between the Intercooler and the throttle body on turbo cars

4. Rempve the screw that holds the coolant pipe to the water pump

5. Remove the screw that holds the coolant pipe in the front left of the engine

6. Remove the hose to the throttle body pre-heater

7. Remove the thermostat housing and remove the thermostat

8. Refit in Reverse

4 Cylinder Thermostat Removal

1. Drain the coolant by opening the drain cock or removing the lower radiator hose. Remove the lid to speed up process

2. Remove the throttle body ccover on turbo cars

3. Remove the bypass hose and the pressure pipe between the Intercooler and the throttle body on turbo cars

4. Rempve the screw that holds the coolant pipe to the water pump

5. Remove the screw that holds the coolant pipe in the front left of the engine

6. Remove the hose to the throttle body pre-heater

7. Remove the thermostat housing and remove the thermostat

8. Refit in Reverse

Check the freezing point of the coolant you are removing just to make sure the coolant is antifreeze.Usually you would refill with full strength coolant if just draining and refilling the rad.

hi sounds to me that your rad is blocked or sprung a leak first drain the rad and then refill with a rad flush run the engine for about 15 mins then drain be careful it will hot /when your engine is cool fill useing rad weild or another brand run this for another 15 min drain and refil as normal if this dose not work i think your looking at a new rad hope this helps if so please give me a rating best of luck pete

Slap on those vinyl gloves because the ethylene glycol in antifreeze can cause skin damage - however we recommend this because the antifreeze feels like engine oil.With your catch pan in place, remove the radiator drain plug and collect all old coolant. Immediately dispose of the coolant as required by environmental laws - if you are to surrender the old coolant at a waste management facility, be sure you use containers which can be properly sealed to avoid spillage, etc.To expedite the draining process, remove your radiator fill cap to allow air to enter the system.
Also be sure to remove all coolant from your radiator reservoir. We suggest you use the gravity siphon trick - just be sure not to ingest any coolant.

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Watch the old coolant as it exits the system - this will give you a good idea of your vehicle's cooling system condition.If you see metal flakes, oily surface, white flakes, etc .. you can make a diagnosis of your engine's coolant system.
Essentially, if you see anything but coolant and some very minor debris, it can indicate the early signs of cooling system failure.When all coolant has been drained from the radiator, replace the radiator drain plug and then fill the system with plain tap water to dilute remaining antifreeze in the engine block.
With the cooling system refilled with tap water, replace the radiator fill cap and run the engine allowing it to reach operating temperature.When the engine's cooling fan turns on, it is an indication that the vehicle's thermostat has opened, allowing the freshly added water to circulate through the engine thus diluting the remaining coolant. Allow the engine to run for a few minutes before shutting it off.
At this point, you can either wait until the engine cools off, or take fate in your own hands and continue the flushing process.Repeat the draining process being sure to once again collect and dispose of all waste coolant.
At this point, if you have opted to purchase a radiator flush kit, you should refill the cooling system with tap water and add the caustic fluid as directed.
Run the engine for as long as the radiator flush kit calls for (usually less than 10 minutes).

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Once again, drain the cooling system, collecting all waste fluid. This is the last time you will be required to collect engine coolant during this process.Now that the cooling system is empty, replace the radiator drain plug and refill the cooling system with distilled water only. The reason that you should only use distilled water at this point is to avoid mineral deposits which will deteriorate your cooling system over time.
Once the cooling system has been completely filled, start the engine to allow the water to circulate. Once again remove the radiator drain plug. As the engine runs, pour fresh distilled water into the radiator fill hole at the same rate that it exits the system.Continue this process until the water being drained from the radiator appears to be clear and free of debris. Once you are satisfied with the drain water's appearance, stop the engine and allow all remaining water to drain out.Replace the radiator drain plug and prepare to mix your distilled water and coolant.
Be sure to mix your coolant to the ratio recommended by your manufacturer. In most cases, the ratio is 50% distilled water and 50% coolant.
As a tip, mix the coolant and water in a third container being sure to observe the proper ratio.As you mix your water and coolant, use your hydrometer to measure the specific gravity - this will give you a good idea of whether or not you are mixing the coolant and water properly.
Once you have mixed enough coolant and water to fill your engine's coolant system entirely, grab a funnel and place it in the radiator fill hole.Fill your radiator at a rate of no more than:
{ 1 L/min. \ 1.1 US qt./min. \ 0.9 Imp. qt./min. }.
Continue the filling process until the coolant reaches the bottom of the fill neck. Now fill the radiator reservoir to the full mark.
With the radiator fill cap still off, start the car and allow it to idle. As the engine runs, continue to add coolant as air escapes the engine and cooling system.As you top up the radiator, be sure to "burp" the cooling system by firmly squeezing the radiator hoses (both upper and lower). Continue to squeeze and release the hoses to help push any errant air bubbles out of the system.
Once you are unable to fill the radiator any further, replace the radiator fill cap and stop the engine - you are finished.

COOLANT CHANGEON THE RADIATOR (LOWER DRIVERS SIDE FACING THE MOTOR) THERE IS A PLASTIC LIKE PLUG THAT YOU TURN COUNTER CLOCKWISE ABOUT 3/4 OF A TURN, THEN YOU CAN PULL IT OUT ABOUT 1/2 AN INCH THIS WILL DRAIN THE RADIATOR, THEN YOU CAN PUSH THE PLUG BACK IN AND TURN IT UNTIL YOU FEEL IT LOCK BACK IN PLACE. REFILL RADIATOR WITH 3 PARTS COOLANT TO 1 PART WATER.
1998-'99 Intrigues equipped with the 3800 engine have a specific process for replacing antifreeze. It is somewhat of a lengthy process and you should refer to your owners manual for doing this. After you empty and flush your system with water (garden hose), only fill the system with green 50/50 antifreeze, NOT Dex-Cool. Avoid Dex-Cool. If you bring your Intrigue to a shop to get serviced, make sure and inform whoever doing repairs and/or leave a note (clearly visible) to NOT use Dex-Cool if they're doing any work pertaining to cooling system.

FIRST OF ALL YOU HAVE TO DRAIN SOME COOLANT.JUST ENOUGH SO COOLANT WONT FLOW ALL OVER ENGINE.AND COOLANT TO EXPENSIVE ON THE GROUND.TO GET TO THERMOSTAT.YOU HAVE TO DISCONNECT CONNECTORS TO MAF EGR IDLE SPEED CONTROL AND IAT SENSOR.. REMOVE THROTTLE AND SHIFT CABLES FROM BRACKET.REMOVE AIR FILTER ASSEMBLY WITH MASS AIR FLOW SENSOR.REMOVE BOTTOM PORTION OF AIR FILTER HOUSING.REMOVE COOLANT HOSES FROM THROTTLE BODY.THEN REMOVE THROTTLE BODY ASSEMBLY.YOU HAVE TO DISCONNECT SMALL COOLANT HOSE TOP WATER PUMP.REMOVE SMALL BOLT THAT HOLDS METAL COOLANT LINE TO WATER PUMP.THIS LINE HAS TO BE MOVE JUST ENOUGH SO YOU CAN REMOVE THROTTLE BODY.ONCE THROTTLE BODY OUT THE WAY YOU CAN REMOVE THERMOSTAT.BESURE WHEN YOU PUT EVERYTHING BACK TOGETHER.REPLACE THROTTLE GASKET AND THE COOLANT HOSES COME OFF THROTTLE BODY BESURE TO USE OLD COOLANT HOSES MEASUREMENTS FOR NEW HOSES MEASUREMENTS MAKE SURE YOU BUY THE CURVE HOSE FOR THROTTLE BODY. DONT TRY TO USE STRAIGHT HOSE IT WILL KINK AND CAUSE NO COOLANT FLOW.WHEN YOU ARE DONE.FILL COOLANT BACK TO CORRECT LEVEL AND BLEED COOLANT SYSTEM.

Hope you didn't run your car much when it overheated. this could mean trouble if you did. But as suggested, replace the thermostat.drain the coolant if it has any left, below the thermostat level. It is located at the end of one of the radiator hoses . the housing has a bleeder screw at the outlet of the housing. then remove the housing. the thermostat is located underneath. be careful to replace it the same direction. Clean the contact points on the engine and the housing.And place a little bit of silicone gasket sealer on the gasket and the housing . Make sure the thermostat is settled on the engine part. Carefully replace the housing. And reinstall everything back. refill with coolant half/half water and coolant.Start the car and let it heat up. Then bleed the system with the bleeder screw turning it counter clockwise until all that comes out is coolant. refill radiator again and repeat. Until radiator is full.