Yep, I agree with RASMATAZ, aslo, you could have an air bubble inside the core as well, here is a guide that will help you fix the problem as well.
https://www.2carpros.com/articles/car-heater-not-working
Here is how to bleed the air out of the heater core if flushing it with a garden hose does now work. Check out the images (below). Please let us know what happens.
Image (Click to make bigger)
Saturday, September 7th, 2024 AT 8:32 AM