When I start the car, the temperature guage goes to the normal position, the air coming from the heat vents is cold. When I accelerate the temperature coming out the vents rises and when I decelerate the temperature from the vents gets cold.

Possible defective temperature sensor or wiring issue. Check to see if the heat coming out of the vents stays at a constant temperature when this problem is happening. If it goes from hot to warm/cold when the temp guage is messing up, you may have a head gasket isssue developiing

most likely the hot/cold blend door actuator is not working and these are all electric not vacuum controlled

Make sure that your radiator is filled to the proper level. If it isn't, the heater core may not be filled, so no heat can be extracted from it.

The heating coil is probably getting plugged up. You may have heat at idle or slow speeds, but once you get going, there is not enough coolant going through it to stay warm. Get the system flushed or replace the heating coil.

Heater core may be clogged. Try flushing it to see if water flows through freely. Also check the heater water control valve for restrictions.

make sure you have plenty fluid in the radiator and the bottle. sounds like it is low.

The blend door may be malfunctioning if the heater core gets hot enough to heat at any given time.

-No. When you rev up, the fan pulls more air trough the radiator
so it get cooler. This is suppose to be. This is good.
-Don't worry about. You're good.
-But if you drive and temperature drop to very low then the thermostat stuck open. It need to be replace.

Good luck


Mai

Sounds like the Coolant is not full and has a air bubble. It is very important to have the system filled complete. That would be the first step.Good luck and have a great day.

sounds like your low in coolant. this will cause an air pocket in engine and cause erratic temp readings/loss of heat check coolant in radiator when cold. and add