Heater not working properly

JACKNUT

MEMBER
2005 BUICK LA CROSSE
3.8L
V6
177,000 MILES

I filled coolant and bled system. Gauge shows in 1/4's it never goes over between 1/4 and half. It doesn't over heat. But the thermostat was changed. I don't know what temperature thermostat was put in or why it was changed. But heat isn't what it should be.

1 Reply

JACOBANDNICKOLAS

MECHANIC
108,133 POSTS

Hi,

No heat can be caused by a few things. The first thing I would suggest is to determine if both heater core hoses are getting hot when the engine is warm and the heater is on high. If they aren't, then suspect the heater core is plugged. So, check that first.

If they are getting hot, then suspect the blend air door in the vehicle isn't working properly.

Here is what I suggest. First, take a look through this link and let me know if anything helps.

https://www.2carpros.com/articles/car-heater-not-working

If it doesn't, with the engine warm and the heater on, see if both heater core hoses get hot. Let me know the results.

If both get hot, then we need to check the blend air door. I attached a pic below showing the location. remove it and see if it moves when you change from cool to heat.

Let me know what you find or if you have other questions

Take care,
Joe

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