FRAMING JOHN DELOREAN - ON VOD www.framingjohndeloreanfilm.com
Results 1 to 10 of 10

Thread: Heater control valve not getting vacuum?

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

    Posts:    2,405

    My VIN:    01049

    Heater control valve not getting vacuum?

    My A/C, while it is cold, isn't as cold as it can be - I get ~55 out of the vents, not ~40. This has been going on since last summer. Yes, I have put the A/C gauges on, and everything checks out there.

    I noticed that when put on the max setting, that the heater control valve in the engine bay wasn't pulling its flap shut. I thought that maybe this was because of my A/C mode switch diaphragm, which I have heard hissing for as long as I can remember.

    So I changed the diaphragm out yesterday. That made no change in the operation of the heater control valve. I pulled the vacuum line out of the heater control valve, and found that it isn't pulling vacuum.

    Not sure how to proceed from here.
    -Mike

    My engine twists my frame.

    1981 DeLorean, Carb LS4 swap completed
    1999 Corvette, cam/headers/intake manifold, 400 rwhp
    2005 Elise, stock
    2016 Chevy Cruze

  2. #2
    Quietly enjoying ownership Cory W's Avatar
    Join Date:  May 2011

    Location:  North Bay, Ontario, Canada

    Posts:    481

    My VIN:    4692

    Were you been in the center console around that time? Any vacuum hoses pull off there? Maybe rearranged at the mode switch somehow? Check all junctions as well back there, since it's not impossible for them to come off at that point.

  3. #3
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

    Posts:    2,405

    My VIN:    01049

    Nope, hadn't been in the console around the time the control valve stopped, um, controlling.

    From my experience replacing the diaphragm the other day, you aren't kidding; super easy to knock things loose back there!
    -Mike

    My engine twists my frame.

    1981 DeLorean, Carb LS4 swap completed
    1999 Corvette, cam/headers/intake manifold, 400 rwhp
    2005 Elise, stock
    2016 Chevy Cruze

  4. #4
    Quietly enjoying ownership Cory W's Avatar
    Join Date:  May 2011

    Location:  North Bay, Ontario, Canada

    Posts:    481

    My VIN:    4692

    Quote Originally Posted by opethmike View Post
    Nope, hadn't been in the console around the time the control valve stopped, um, controlling.

    From my experience replacing the diaphragm the other day, you aren't kidding; super easy to knock things loose back there!
    The line that isn't pulling vacuum, have you followed it backwards? You never know if you may find a leak, or a line disconnected further back Nothing is impossible; you could even find a clog in a line? Maybe a line got pinched somewhere...

  5. #5
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

    Posts:    2,405

    My VIN:    01049

    Quote Originally Posted by Cory W View Post
    The line that isn't pulling vacuum, have you followed it backwards? You never know if you may find a leak, or a line disconnected further back Nothing is impossible; you could even find a clog in a line? Maybe a line got pinched somewhere...
    Yeah, I'll do just that eventually. Summer doesn't get brutally hot around here, so my A/C is perfectly serviceable for now.
    -Mike

    My engine twists my frame.

    1981 DeLorean, Carb LS4 swap completed
    1999 Corvette, cam/headers/intake manifold, 400 rwhp
    2005 Elise, stock
    2016 Chevy Cruze

  6. #6
    Senior Member Kevin's Avatar
    Join Date:  May 2011

    Location:  Blacksburg, VA

    Posts:    231

    My VIN:    3472 (former)

    Club(s):   (DCVA) (DCUK)

    Bumping this because I'm having the same problem. Did you ever figure out your issue, Mike?

    I went to a shop because my A/C hadn't been working, figured I needed a recharge since I hadn't turned on my A/C in over a year. Turns out my compressor and refrigerant are fine. Then I noticed the vacuum line wasn't plugged into the hot water valve. That seemed to fix things for the most part but I know it should be colder.

    How likely is it for a hot water valve to fail? I don't have a vacuum gauge at the moment to test mine. Is it more likely to be a vacuum leak elsewhere?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •