I have no heat coming frommy vents.my thermostat is good

u hav enough fluid--also there mite b air in the system--water pumps cant circulate that--may be coming from a worn engine--is the blower motor wirkin or the vents

IF YOU CAN'T FEEL THE AIR FLOW OUT BUT YOU HEAR THE BLOWER MOTOR WORKING, BEHIND THE GLOVE BOX IS A CABIN FILTER.REPLACE FILTER
IF YOU HAVE GOOD AIR FLOW BUT NO HEAT:
1;VACUUM LEAKING TO HEATER CONTROL
2;WATER PUMP GOING BAD / NOT CIRCULATING COOLANT,HIGH RPM/MORE COOLANT TO THE HEATER CORE
3;OPEN THERMOSTAT/ENGINE TEMPERATURE TO LOW
1;CHANGE THE DIRECTION FROM VENTS TO FLOUR TO WINDSHIELD. IF NOTHING HAPPEN IS THE VACUUM
2;RUN THE ENGINE INSIDE ON WARM PLACE ON IDLE.NOTE THE GAUGE IF PAS 1/2 TO 3/4. IF PAS 3/4 MARK REPLACE WATER PUMP
3;IF GAUGE STAY BELOW 1/2 REPLACE THERMOSTAT
GOOD LUCK

You mean turn on heat but get Only cold air ?
Is it front heater work and hot?
If so. The heater hose to the rear core is plug. Need to flush it from both direction and make sure is full of coolant (Water).
You should be good to go.

Mai Lor

If the heater valve operate properly then the line to the heater core is plug.
Check & replace or flush.

Good luck

Mai

If there is cold air coming out the vents than its not a thermostat. The thermostat gullets the temperature of the engine not the temp of the heater which bypasses the thermostat. If there is never any heat out the vents than there are two possibilities. The coolant level is to low. The first thing you will notice if the coolant level gets to low is the lack of heat out t

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

ifs theres air coming out of the vents could be a thermostat if theres no air could be blowermotor

Thermostat -stuck open

If the temperature is cold outdoors, this can be a symptom of a stuck open thermostat. With the thermostat stuck open the engine never gets warm, so it won't give good heat. It's not expensive to get a new one, and they are easy to replace, so take it in and have it checked. Another symptom of that is very low gas mileage in the cold weather.

Are you sure there is not a air pocket in the engine after changing water pump,
there is only 1 thermostat

Are your electric fans engaging or turning on?