Chasing Heater Problems - It's 30F outside and I'm cold inside!
 

Hey all,

I've recently had service performed on my heating system, and I'm still at operating temps! I'm hoping you can help me determine what to check next...

I have an '87 Carrera with auto heat. I feel some heat coming out and have confirmed that the engine blower motor is running. But the rate of heating blowing into the cabin does not change from level 1 to level 10. My understanding that the foot-well blowers have 3 speed levels which are set by the dial between the seats (1-10):

1. Low Speed (1-3)
2. Medium Speed (4-6)
3. High Speed (7-10)

Is this correct? I've recently had the heater flapper boxes services and confirmed that the dial between the seats is fully opening the flapper boxes at level 10.

Any guidance on this one?

If you're getting some heat then your autoheat op rod is likely functioning; my bet is that your flapper boxes aren't closing properly/fully, sucking in cold ambient air that dilutes the heated air coming off the HEs.

HTH

I would simply get under the car and see if everything looks the way it should. Properly hooked up etc.

Check the cables for full opening of the flapper boxes. Like the last poster said check the hoses,boxes cables etc...

In dry weather my 911 heater will cook me withing a couple of minutes on the coldest day. If you are not roasting you must have a massive air leak in the heat ductwork.

Guys - Thanks for the advice. I just got the car back from the mechanic on Friday, and he fixed a problem related to the flapper boxes not opening/closing properly. I'll double check this weekend.

It's strange to me that the volume of hot air coming out of the vents/foot-well does not increase from setting 1 to setting 10.

Auto heat.
 

It should definitely change (increase) as per our '86.

Can you hear the fans running? On the 10 setting it should sound like a hurricane blowing inside the cabin. These are not particularly quiet blower motors. If you don't hear them running I suspect the fuses are blown or they are frozen.

Do you both hear and feela difference as it increases speeds? Any suggestion on what to check first?

heat
 

pm sent