Hey all; so, my 1972 Skylark's A/C blows cold, but I have a vent issue (I believe) and I'm curious what everyone's thoughts are. So, what's happening is as follows: Turn A/C on, blows cold at the floor vent (does not blow air through any other vent), get moving (around 1500-2k rpm or 35-40mph) the dash vents start blowing out the cold air. I'm not sure if this is a possible vacuum leak or honestly what is happening. I've never really experienced this nor have a few people I've talked to with classic cars. So, any advise/opinions would be greatly appreciated. Thank You
Also wondering if anyone knows what kind of radiator would've come stock in a 1972 Buick Skylark 350 w/ A/C? 2 or 3 row? Thank You
It should be a three row with AC. GM (at least Chevrolet) learned their lesson the hard way with the two-row radiators in the big cars, in those days. Ever seen a blue torque converter? Take a look at the vacuum manifold on the back of the AC switch and make sure it's plugged in tight. Also, look at the vacuum lines in general, under the hood. I suspect it's a vacuum leak. It is entirely possible that the switch itself has developed a vacuum leak. You can verify that by using a small piece of vacuum hose and holding it up near the switch.
You might want to check the AC vacuum plenum door that is located behind the kick panel on passenger side (below dash). There is a vacuum line that operates that door that attaches right behind the kick panel and could be rotted off or disconnected. This caused the same symptoms to described on my 71 skylark. Worth a try, you may get lucky like I did and fix the air routing problem with a new section of hose. John
Will do both tomorrow morning and see. I figured it was a vacuum leak, just a strange scenario to have and wasn't sure if anyone has ever had something similar happen. Thank You
It was the vacuum line; replaced and now cold air is blowing cold through all vents. Ready to take on this 104 degree CA heat..
Pay dirt! Glad you were successful.... I'm amazed any of those "spaghetti " vac lines survived this long. I'm not sure but I would think anytime we plug a vacuum line leak we also improve the overall performance of the carburetor as needs max vacuum to achieve best fuel air mix. Larry or one of our tune up experts might have some thoughts on how critical a small air leak can impact fuel delivery.
