If you have a hot running engine, the below information might help to alleviate the problem. Overheating can be caused by a multitude of other things from improper ignition timing, to spark pre detonation because of gasoline quality. It is difficult to diagnose these conditions long distance.
If the engine coolant passages are clogged or have a layer of rust or slime on them, that they will not properly cool the engine block. For this, I would suggest that you use either a commercial coolant system cleaner, or a home made brew that I have used successfully.
I first clean out the heater core by removing the two heater hoses. I drain the heater core through the return side of the heater core hose, by lightly pressurize it with air. I never exceed 10 PSI of air, since I don't want to damage the heater core. By blowing through the return hose, you are actually blowing the crud in the heater core out of it. Then with a garden hose, I run water through the return heater hose till it runs clear.
Remove the lower engine to radiator hose and drain the coolant from the engine block and radiator. Then remove the thermostat. This is located under the top of the engine at the base of the upper radiator hose. Usually it has 2 or 3 bolts holding it into a steel goose neck. You can take the goose neck to the auto parts store for them to match up a new gasket, and while you are there, buy new heater hose, upper and lower radiator hoses, and the water pump by pass hose if your car is so equipped.
Once you have the entire system drained, and the thermostat removed, then reinstall all the hoses, and put about 2 pounds of Arm and Hammer washing soda into the radiator, and fill with water. You might have to use some water just to get the washing soda into the radiator. Fill the radiator to the top with tap water, reinstall the pressure cap and then start the engine. Allow the mixture ample time to circulate at a fast idle. This should take about 30 minutes. Then shut the engine, and remove the lower radiator hose and drain into a container. Be careful not to get scalded. Reattach the lower hose when the engine has cooled.
Wait for the engine to thoroughly cool before adding water. If you put cold water into a hot engine, you will crack a head or engine block. When the engine is cooled down, fill with water again, and run until the engine is warm to the touch. No need to get this rinse water very hot. Drain as above, and again wait for the engine to cool. Then put 2 boxes of baking soda into the radiator and fill with water as above. Run this for a few minutes until the engine is warm to the touch. Drain as above. You are now finished with the block cleaning process.
Remove the upper and lower radiator hoses, and then cut off the heater hoses about 3" from the heater box, and leave the rubber hose on the heater core nipples. This is important so you don't damage the heater core. Now, using a new single edge razor blade, cut along the length of the heater hose being careful not to go too deep on the first cut. You want to relieve the tension that is holding the heater hose to the heater core nipple. Once you have fully slit the heater hose, using a small flat bladed screwdriver, insert it into the cut on the hose, and gently pry the two sides of the hose apart. You want to be careful not to pull on the hose itself, but to gently peal the hose off the nipple. Once you have the hoses off the heater core nipples, then carefully clean the nipples so they are smooth with no traces of the old rubber sticking to them.
Blow out any water that is in the heater core and engine block now.
Using the old heater hoses as a guide, cut new heater hoses to the proper length, and install on the engine block and tighten the clamps. On the heater core nipple, you will have a more difficult time getting these to slip on. You can use any water soluble lubricant, or do as the old timers did, and use some spit! Don't forget to put the clamps onto the hose before you install the hoses. Replace the thermostat and upper and lower radiator hoses. Replace the water pump by pass hose if your car has one. I prefer the molded hoses to the universal flex hoses, but both will work. The new molded hoses no longer come with a spring in the lower hose, so you might consider using the original spring from the old hose in the new hose. The auto parts stores say that the spring is no longer needed. I have no opinion on this claim.
I suggest that you purchase the 50/50 premix anti freeze rather than mixing your own. It is premixed with PH neutral de-mineralized water. If you want to mix your own, then purchase de-mineralized water for mixing. Tap water today has too many minerals that are not good for the cooling system. You now have a clean cooling system that should serve you well. If you change coolant every 2 or 3 years, then you will not have to do this cleaning again. One of the reasons to change coolant, is that the water pump lubricating properties of the coolant start to break down with time. The freeze protection of the coolant will always be present, no matter what the age of the coolant.
Final precaution. The coolant and drained water contain poisons, that will make children and pets sick, and possibly fatal if ingested. Make sure to properly dispose of all drained components.
If the engine coolant passages are clogged or have a layer of rust or slime on them, that they will not properly cool the engine block. For this, I would suggest that you use either a commercial coolant system cleaner, or a home made brew that I have used successfully.
I first clean out the heater core by removing the two heater hoses. I drain the heater core through the return side of the heater core hose, by lightly pressurize it with air. I never exceed 10 PSI of air, since I don't want to damage the heater core. By blowing through the return hose, you are actually blowing the crud in the heater core out of it. Then with a garden hose, I run water through the return heater hose till it runs clear.
Remove the lower engine to radiator hose and drain the coolant from the engine block and radiator. Then remove the thermostat. This is located under the top of the engine at the base of the upper radiator hose. Usually it has 2 or 3 bolts holding it into a steel goose neck. You can take the goose neck to the auto parts store for them to match up a new gasket, and while you are there, buy new heater hose, upper and lower radiator hoses, and the water pump by pass hose if your car is so equipped.
Once you have the entire system drained, and the thermostat removed, then reinstall all the hoses, and put about 2 pounds of Arm and Hammer washing soda into the radiator, and fill with water. You might have to use some water just to get the washing soda into the radiator. Fill the radiator to the top with tap water, reinstall the pressure cap and then start the engine. Allow the mixture ample time to circulate at a fast idle. This should take about 30 minutes. Then shut the engine, and remove the lower radiator hose and drain into a container. Be careful not to get scalded. Reattach the lower hose when the engine has cooled.
Wait for the engine to thoroughly cool before adding water. If you put cold water into a hot engine, you will crack a head or engine block. When the engine is cooled down, fill with water again, and run until the engine is warm to the touch. No need to get this rinse water very hot. Drain as above, and again wait for the engine to cool. Then put 2 boxes of baking soda into the radiator and fill with water as above. Run this for a few minutes until the engine is warm to the touch. Drain as above. You are now finished with the block cleaning process.
Remove the upper and lower radiator hoses, and then cut off the heater hoses about 3" from the heater box, and leave the rubber hose on the heater core nipples. This is important so you don't damage the heater core. Now, using a new single edge razor blade, cut along the length of the heater hose being careful not to go too deep on the first cut. You want to relieve the tension that is holding the heater hose to the heater core nipple. Once you have fully slit the heater hose, using a small flat bladed screwdriver, insert it into the cut on the hose, and gently pry the two sides of the hose apart. You want to be careful not to pull on the hose itself, but to gently peal the hose off the nipple. Once you have the hoses off the heater core nipples, then carefully clean the nipples so they are smooth with no traces of the old rubber sticking to them.
Blow out any water that is in the heater core and engine block now.
Using the old heater hoses as a guide, cut new heater hoses to the proper length, and install on the engine block and tighten the clamps. On the heater core nipple, you will have a more difficult time getting these to slip on. You can use any water soluble lubricant, or do as the old timers did, and use some spit! Don't forget to put the clamps onto the hose before you install the hoses. Replace the thermostat and upper and lower radiator hoses. Replace the water pump by pass hose if your car has one. I prefer the molded hoses to the universal flex hoses, but both will work. The new molded hoses no longer come with a spring in the lower hose, so you might consider using the original spring from the old hose in the new hose. The auto parts stores say that the spring is no longer needed. I have no opinion on this claim.
I suggest that you purchase the 50/50 premix anti freeze rather than mixing your own. It is premixed with PH neutral de-mineralized water. If you want to mix your own, then purchase de-mineralized water for mixing. Tap water today has too many minerals that are not good for the cooling system. You now have a clean cooling system that should serve you well. If you change coolant every 2 or 3 years, then you will not have to do this cleaning again. One of the reasons to change coolant, is that the water pump lubricating properties of the coolant start to break down with time. The freeze protection of the coolant will always be present, no matter what the age of the coolant.
Final precaution. The coolant and drained water contain poisons, that will make children and pets sick, and possibly fatal if ingested. Make sure to properly dispose of all drained components.
