No Heat- smoke from the auto sensor
02-02-2008, 08:20 PM
#1
Track Day
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No Heat- smoke from the auto sensor
Hey everyone- before I begin, I want to let you know I have read many threads with no avail.
My 1987 S4 is blowing luke warm, definitly not warm enough to heat the cabin. When I shift the temperature guage to cool, the temperature remains the same. At one point a while back I do remember a puff of smoke come out of the sensor vent. The blower works fine, I check the relays and fuses, and they are fine. Any ideas? I'm having to park it and not drive it as it is way to cold out to drive without heat. Any ideas?
My 1987 S4 is blowing luke warm, definitly not warm enough to heat the cabin. When I shift the temperature guage to cool, the temperature remains the same. At one point a while back I do remember a puff of smoke come out of the sensor vent. The blower works fine, I check the relays and fuses, and they are fine. Any ideas? I'm having to park it and not drive it as it is way to cold out to drive without heat. Any ideas?
02-02-2008, 08:42 PM
#2
Team Owner
is the coolant level correct? If not top it up.
Is the heater control valve working, remove the lower part of the aircleaner housing to inspect this, first when the car is off ,then start it the HCV should open when vacuum is applied.
If your HCV is older than 5 years now is also a good time to replace it and the short hose that connects the HCV to the rear of the right cylinder head
Is the heater control valve working, remove the lower part of the aircleaner housing to inspect this, first when the car is off ,then start it the HCV should open when vacuum is applied.
If your HCV is older than 5 years now is also a good time to replace it and the short hose that connects the HCV to the rear of the right cylinder head
02-03-2008, 02:12 PM
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Track Day
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Good- I'll try this- is there any way to repair the HCV?
Any other ideas? Would one of the auto sensors cause the heat to not work? Is there a way to bypass the sensors?
Any other ideas? Would one of the auto sensors cause the heat to not work? Is there a way to bypass the sensors?
02-03-2008, 03:50 PM
#4
Race Director
One other problem area is the solenoid that controls the HCV can fail...& when it does its failure mode is to apply vacuum...which effectively closes the valve....so no heat....this is assuming you have vacuum, if you don't then the HCV would be open all the time
How do I know....I went from a zero vacuum constant heat....to a zip tied closed heater valve, to a repaired vacuum system...then no heat.....it was the solenoid....about $25 from intl....
How do I know....I went from a zero vacuum constant heat....to a zip tied closed heater valve, to a repaired vacuum system...then no heat.....it was the solenoid....about $25 from intl....
02-09-2008, 11:12 PM
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I am trying to find the HCV on PET- does anyone know the part number? I am going to check this to see if it the problem. What should I be looking for to determine?
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02-09-2008, 11:31 PM
#8
Team Owner
the heater control valve is on the right side rear cylinder head under the air cleaner lower housing , it must be removed to see it.
If you replace it, it is almost mandatory that you also replace, the short hose that connects it to the head.
You should probably test your vacuum lines at the HVAC junction block a myti vac tester will do the trick, .remove the left side console cover and you will find the bottom of the HVAC vacuum line assembly, do one line at a time see whats not holding vacuum, also test that your getting vacuum from the engine
If you replace it, it is almost mandatory that you also replace, the short hose that connects it to the head.
You should probably test your vacuum lines at the HVAC junction block a myti vac tester will do the trick, .remove the left side console cover and you will find the bottom of the HVAC vacuum line assembly, do one line at a time see whats not holding vacuum, also test that your getting vacuum from the engine
