check the thermostatic switch(turns on and off fan) check engine temp sensor ect.
This question is not complete. . Need to know if you've replaced radiator, thermostat, hoses etc. Are you asking this question *after* yo checked the thermostat, changed, added or drained the system?
Bad thermostat maybe?
im having the same problem with my 1994 I've replaced the heater core,thermostat,radiator,i checked the coolant, and it's not over heating or nothing and still no heat lol
You might have bad actuator that opens and closes airways.
The radiator may be plugged. Take it to a radiator shop.
If you have an old ISUZU Trooper, the radiator thermostat may be not working. Therefore, it will not let cool water from the radiator into the hot engine, even if the radiator is full. Have the thermostat checked and replaced, if necessary. Good Luck
Hi have you checked the radiator for blockage if it is blowing water back out the radiator this could be the problem.
Have you checked your thermostat?
Intake manifold gasket leak? (Never heard of a heat sensor). Many possibilities.
Have you gone through an checked your waterpump / waterpump hose to make sure they're ok?
Replace the coolant, thermostat, turn off the A/c, in emergencies drive with the heater on, increase the air flow through the radiator, have your radiator checked for blockage.
first of all, do you have the right thermostat? ie: winter, summer. if so i would get the radiator checked, it may be getting pluged.