wm_reed Posted November 16, 2012 Share Posted November 16, 2012 Newer owner of 92 Loyale Sedan (2WD, 1.8L, SPFI), Vacuum operated climate controls. 1st heating season: Heat blows out of main vents only until vehicle is driven for ~15 minutes. The pushbutton controls will then start working for defrost or floor (as selected). Car seems very sensitive to slight acceleration where it will then cause the heat to blow out the main vents until you come way out of the gas. This doesn't seem right! I have already confirmed with a hand pump that the actuators work fine. How much vacuum is normal at the Heater switches? Is this a Vacuum Tank issue? Vacuum Leak? Bad pushbutton controls? How do I get the air to blow where I need it when I need it?? Suggestions/ideas are appreciated??? Link to comment Share on other sites More sharing options...
scoobiedubie Posted November 16, 2012 Share Posted November 16, 2012 The stiff plastic pressure tubes that come out of the back of the controls and then plug into junctons, can easily come out of those junctions or become loosened so that you don't have a good seal. Check those. Those tubes lead to controls that operate the levers that divert the heated air flow. Link to comment Share on other sites More sharing options...
TomRhere Posted November 16, 2012 Share Posted November 16, 2012 The stiff plastic pressure tubes that come out of the back of the controls and then plug into junctons, can easily come out of those junctions or become loosened so that you don't have a good seal. Check those. Those tubes lead to controls that operate the levers that divert the heated air flow. Also check the vac lines under the hood. Cracked, loose fitting hoses can cause that to happen. If the check valve in the vac line from intake manifold to White canister (on PS strut tower) is bad you'll have the same issue also. Link to comment Share on other sites More sharing options...
MilesFox Posted November 16, 2012 Share Posted November 16, 2012 check in the driver side footwell just behind the radio to make sure the vac lines are not loose. they are on a little rubber manifold, if you will. check the condition of the vac canister under the hood, and the nylon lines to it. Link to comment Share on other sites More sharing options...
Gloyale Posted November 16, 2012 Share Posted November 16, 2012 I think you need a new check valve. It's supposed to be built into the reserve tank under the hood, but sometimes you need to add another one. Link to comment Share on other sites More sharing options...
Skylar Posted November 16, 2012 Share Posted November 16, 2012 I'm kind of having the same troubles as well, I deleted my CC system and now my defrost won't work I've found my lines for the heater controls down by my feet and I seem to be missing line #3 ? Not sure if it was ever there but I have nothing to connect vacuum line #1 off of the white canister too ... Here's my pic of my vac lines by my feet, no line going in either direction on top Sorry, not trying to thread jack ya here just trying to figure out my heater situation as well ! Link to comment Share on other sites More sharing options...
wm_reed Posted November 17, 2012 Author Share Posted November 17, 2012 Mine is identical. Appears original. Link to comment Share on other sites More sharing options...
presslab Posted November 17, 2012 Share Posted November 17, 2012 I think you need a new check valve. It's supposed to be built into the reserve tank under the hood, but sometimes you need to add another one. Yes, the one inside the tank fails, I had to add another valve as well. Link to comment Share on other sites More sharing options...
wm_reed Posted November 19, 2012 Author Share Posted November 19, 2012 Based on suggestions................... 1. Using a hand held vacuum pump I proved no vac leaks between the intake manifold and the off button on the heater controls. 2. Proved that the check valve in the vac tank was shot. Added an in line vac check valve ($5 at Napa) upstream of the vac tank. 3. Tested again - I can hear a vac leak in the dash near the Heater Control pushbuttons. The leak is intermittent and is gone sometimes after the car has been driven (car cabin hot). The vac leak is the worst when the defrost pushbutton is depressed. Seems to be gone when heat is depressed. **The added in line check valve did make a difference during this test (when accellerating the heat did remain where selected)** 4. Removed and inspected 4 Vac lines that connect to the back of the heater controls. They were all intact. Applied Vac to each line going to vac motors proving what was what and no leaks. Hoses are labeled: #1 - goes to floor #2 - goes to Defrost #3 - is the vac line coming from the intake manifold #4 - goes to the Recirc Based on my findings, The vacuum leak seems internal to the Heater Controller pushbuttons. I don't know why the change in the vac leaks when everything warms up, but that is what seems to happen. Until I can find a working Heater Controller I have plumbed the 4 vac lines to an access below the ignition switch and will jumper the vac line I need so we can put the heat where it is needed, when it is needed. Link to comment Share on other sites More sharing options...
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