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  1. #1

    Default Coolant Leak Question

    Hey Guys, brand new member here. Have been hanging around and reading for a while though. Alot of good info and knowledge to be had from you.

    Anyway, a little background before my question. I've got a 98 Suburban, 5.7 Vortec, 160k, 2WD, Auto.

    A little while back I had to replace the intake gasket. And about a week later, started to see coolant again. Thought it was the gasket again, but lo and behold, it's coming from somewhere else. And it's the "somewhere else" that I need help with.

    It seems to be leaking from a plastic housing valve that has a small vacuum operated diaphragm attached to it. In addition, there are four 1" (ish) coolant hoses coming out of the plastic housing. Since it's dark here, the only 1 that I can positively tell where it's coming from is the top of the water pump. The leak seems to be coming from the valve body itself or possibly one of the connection points for the hoses. My best guess is it has got something to do with the heater system.

    It is located in between and about 6" below the coolant resevoir and the intake filter housing. Some of you probably already know what I'm talking about, but i'm at a loss on this one. I have also attached a few pics to kind of clarify my rambling.

    Thanks for any and all assistance! Greg
    Attached Thumbnails Attached Thumbnails IMAG0067.JPG   IMAG0069-2.JPG   IMAG0071.JPG  

  2. #2


    that is a heater vacc ported switch. it stops the flow of coolent to the heater core until it is at running temp. you can replace the part new or from a junk yard (i got lucky a few times) or by-pass it and put a golf tee or screw in the vacc line to not have a leak......mike
    Michael Collins
    1993 4X4 Suburban
    many other toys as well

  3. #3


    Thanks for the response!

    So, if I bypass it on a temp basis, will that essentially stop the flow to the heater core for good?

    Also, what part name could I look up or ask for? I've looked around on a few internet sites and am having no luck finding anything related to heater, ported, switch, vaccum or any combination of terms... Is there another name that it might be listed under? Thanks again, Greg

  4. #4


    I found it by searching "heater control valve"
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  5. #5


    Thanks Shorty. After I saw your post, I looked it up and AZ had one for a whopping $14. I guess I'll pick one up tomm and replace it. Just in time too, my son and I have a camping trip in a few days and that's the last thing I needed to do was leave a trail of coolant all the way to the mountains and back! Thanks again guys.

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