Q: Low coolant temperature, thermostat issue

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The dash in my car was showing the check engine light illuminated. After having done the codes read, this indicated the problem with a low coolant temperature. I was also told that the thermostat might be stuck open. So, I had the thermostat replaced with a new one. I had the hoses and bolts reconnected. After adding coolant, I ran the engine. I made sure there was no air in the system. After the engine ran for about half an hour, I checked the heater. To my surprise, there was no warmth whatsoever. The thermostat seemed to be defective. The car gotten somewhat heated with the last thermostat. What could be the problem now?

Hey there. If a new thermostat has been installed, I believe one of two things could be your issue. Either the thermostat you purchased is somehow faulty even as a brand new part or the cooling fan on your vehicle may be running at all times not allowing the engine to reach operating temperature. I would recommend taking the thermostat back and trying the repair again if your cooling fan is not running all the time. If the cooling fan is running all the time, you may have a short of some kind that is causing this to happen. In this case, the electrical system of your vehicle would need to be thoroughly inspected to determine where the source of the short is located. Due to the fact that thermostats are relatively inexpensive, the quality control on such a part is likely not very good. Therefore, a brand new thermostat may not be brand new quality. As long as the thermostat is not too difficult to access, I would recommend trying the thermostat replacement again. If you would like to have another mechanic take a look at this situation, a certified technician from YourMechanic can come to your home or office to inspect the cooling system and have this issue corrected.

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