Q: Overheating and boiling out the reservoir.

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The issue started with a heater hose busted so i replace it and it was still overheating. Second thing i tried was the thermostat still overheated. Third thing was bypass heater core still overheating. Now i replaced the water pump and still overheating. From what i know i only have left to change is the radiator which i have just dont want to put it on and it no be it. The coolant looks clean and green so its no dirty. I squeeze the left bottom hose while its cooling from overheating and i hear it go back to the reservoir. I squeeze the top right going to the thermostat and same but hose is much hotter. What ends up happening it that it overheats a boils out the reservoir. Also is there a way to position the thermostat wrong? mine doesnt have a bleeder valve its a MURRAY. Any advise?

My car has 220000 miles.
My car has an automatic transmission.

Hey there. The next thing you need to do is confirm the thermostat is opening and test to see if the radiator is clogged or not. Begin by warming your car up. Don’t drive it, just let it idle or hold it on a high idle. Depending on the ambient temperature, this can take a half hour or more for the thermostat to open. You will know the thermostat is open by touching the upper radiator hose. The hose that comes off of the thermostat housing. When it begins to get hot, the thermostat is opening. The stat will cycle open and closed during the warm up process. A motor is not fully warm until the stat reaches a point of equilibrium. Meaning, it stays open at a constant amount. If your car begins to overheat and the upper radiator hose does not get hot, you will need to figure out what is going on with the thermostat. It could be installed wrong or even bad. I have had new stats be bad several times.

If the stat opens correctly and your car is fully warm, take it for a quick spin around the block. Come back to a stop in your driveway or other parking spot, turn the motor off, key off, open the hood and reach in and touch the radiator from top to bottom and side to side. You are feeling for cold spots. They will be obviously cold in comparison to the rest of the radiator. It is normal for the lower part of the radiator to be colder than the top. That only means the radiator is cooling as it should.

If after doing these two things your car still overheats, it is time to consider head gasket problems. You can use a block tester kit from your local auto parts store or you can book and appointment with us. Testing for head gasket problems can be cumbersome and only experience will allow you to make an accurate determination. I recommend a having an overheating inspection to have this accurately diagnosed and corrected.

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