Weak heat/possibly A/C

VPR900

MEMBER
2003 SATURN VUE
3.0L
V6
4WD
AUTOMATIC
197,000 MILES

Hi, I have been having issues with my heat not working. It is very weak (not hot) especially on fan speeds 3 and 4. I have replaced the thermostat, flushed the heater core, replaced the coolant with universal green coolant, not Dexcol. I have tested the 2 blend door actuators and they appear to be working when the knobs are turned or adjusted. Engine temperature gets up to almost 50%.

Both heater core hoses are hot, top more so than bottom.

at this point I am not sure what else I can try.

as far as the A/C is concerned I thought it was not very cool last year but have not tested it out this year. Heat problem has been going on for about 2 years now.

Thanks

2 Replies

KASEKENNY

MECHANIC
18,907 POSTS

These could be related if you have a blend door issue. So we need to clarify how you tested them. If all you did was turn the knob and listen for them to move, we need to go a little further than that. We need to actually access them and watch to ensure they have full travel. Otherwise, just replace them to ensure they are okay. They are not that expensive.

If they are separate issues then the heat issue could be a restricted heater core. It is good that both lines are hot but if the air coming out of the vents is not hot then the heater core may not be getting hot enough. Unfortunately it is not very easy to flush these as most are all multi passage. That means when one passage gets plugged the coolant just goes through a different passage. So when you flush it, it doesn't actually clean it out.

Then if the A/C is weak as well, that could just be the refrigerant level so we need to check that with a pressure gauge.

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

Let me know if there is more detail to what you have done so far and we can go the next step. Thanks

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Saturday, March 21st, 2020 AT 6:50 AM

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

This sounds like a heater core issue. There is a lack of circulation in the core.

https://www.2carpros.com/articles/replace-heater-core

It may have looked clear when you flushed it but still may have a restriction in the core.

Roy

Removal Procedure

1. Drain the engine coolant.
2. Remove the heater outlet hose from the heater core.
3. Remove the heater inlet hose from the heater core.
4. Remove the instrument panel retainer.
5. Remove the shift control bracket. Bracket Replacement in Manual Transmission -- Getrag 5, Transmission Control Bracket Replacement in Automatic Transaxle -- AF33-5, or Transmission Control Bracket Replacement in Automatic Transmission -- VT25-E.

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6. Remove the heater duct screws.
7. Remove the heater duct.

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8. Remove the heater core cover screws.
9. Remove the heater core cover.

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10. Remove the heater core pipe cover screw.
11. Remove the heater core pipe cover.
12. Remove the heater core pipe foam seal.

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13. Grasp the heater core at end tanks and remove heater core. Spray the perimeter of the heater core seal and the heater core pipes at the front of dash with a soap and water mixture to ease removal.

Images (Click to make bigger)