My temp gauge stays on hot but not over heating and the heater is blowing cold

Thermostat is sticking or heater core is blocked.do not keep running it or it is going to ruin the engine. It is running hot regardless if is blowing cool or hot air. Do not keep using the car.

It probably low on coolant. The heater will blow cold when there is not enough water (coolant) to keep the heater core full. Check the radiator (not the overflow reservoir) when it's cool.

Your temp sensor has nothing to do with your heater. The temp sensor needs coolant in order to work properly. So first check the coolant level because if it is low your heater will act the way you describe. Once the coolant gets low enough the heater will blow cold. Another possibility is the radiator cap. After the engine has warmed up it expands when it cools down it contracts. As it is contracting if the cap is weak air can be drawn into the system and cause air pockets to form and will cause the same problem

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These details will help.
Thanks.

To troubleshoot this types of problem,click the link below :----http://howtobyme.blogspot.in/2012/02/heater-blows-only-from-defrost.html
--------Go through the procedure to confirm the issue.

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This will help.Thanks.

well it might be you engions not heating you see the heater draws heat from the ingion but if the thermistat is stuck open then the engion will stay cold and the heater will only blow cold air

jtg

When your engine thermostat has failed or is sticking open, the engine fluid isn't able to reach a temperature that lets your heater core get hot enough to produce worthwhile heat to blow into the passenger's compartment. It is also not good for your engine to run below design temperature.
If you have a dashboard temp gauge, if your thermostat is stuck open, that gauge will probably stay in the cold area.
I would think that that is the problem, and I would have the thermostat changed (not a very difficult or expensive job).
Hope this helps you.

I would start by changing your thermostat.

Switch ig. on, ground the sender unit wire for about 3 seconds see if the temp. gauge moves, if so change sender unit, if not then it is a faulty gauge reader.