pressure testing a heater core

ArtS
ArtS Expert Adviser
edited November -1 in HUDSON
I now have all the parts needed to take my Hornet heater off by-pass circulation but figure I'd pressure test the core first to make sure there are no leaks. My question is, how much pressure should I put on the box to give it a reasonable load but not blow out the core? I figure 7 psi for a normal load (std operating temp) and maybe 15 psi as a test. Does this sound OK? Thanks for your help.

Comments

  • Unknown
    Unknown
    sounds about right to me,are you using the old inner tube method?
  • Aaron D. IL
    Aaron D. IL Senior Contributor
    Yep the onld system only had 7 psi running through it so I souldn't go a whole lot higher. just simulate an overheat pressure load or something.
  • ArtS
    ArtS Expert Adviser
    yorgatron wrote:
    sounds about right to me,are you using the old inner tube method?



    That's right, I'll cut a bicycle inner tube, clamp the free ends onto the inlet and outlet and pump it to 15 psi. Then listen for hissing inside the vehicle and watch for loss of pressure over a few hours.
  • Unknown
    Unknown
    ArtS wrote:
    That's right, I'll cut a bicycle inner tube, clamp the free ends onto the inlet and outlet and pump it to 15 psi. Then listen for hissing inside the vehicle and watch for loss of pressure over a few hours.

    works better if you take it out of the car and submerge it in the sink.

    i tend to carry some aluma-seal in the glove box and not worry...
  • ArtS
    ArtS Expert Adviser
    yorgatron wrote:
    works better if you take it out of the car and submerge it in the sink.

    i tend to carry some aluma-seal in the glove box and not worry...



    You are right, that's going to help reveal any pin holes that need repair. I have not yet taken a good look at the heater box. Is it a big deal to pull it out of the car? Maybe I should do it once and do it right. Thanks for the tip.
  • hudsonguy
    hudsonguy Senior Contributor
    ArtS,



    The heater box is held in place by four phillips screws. Detach the cable to the control valve (if you have one), pull off the defroster hoses, disconnect the wire at the fuse, and that's it! Once you drop that out you'll see two more phillips screws holding the core up there. It's probably more work to disconnect the hoses under the hood, if they've been on there a while.
  • ArtS
    ArtS Expert Adviser
    hudsonguy wrote:
    ArtS,



    The heater box is held in place by four phillips screws. Detach the cable to the control valve (if you have one), pull off the defroster hoses, disconnect the wire at the fuse, and that's it! Once you drop that out you'll see two more phillips screws holding the core up there. It's probably more work to disconnect the hoses under the hood, if they've been on there a while.

    Thanks for the detailed info on dropping the heater box. Sounds like something even I can do! I appreciate your help.
  • bobbydamit
    bobbydamit Expert Adviser
    Buy a 1/2 or 3/4 in tee, plastic, and put a hose from in to out and cut in the middle. attach both ends to the tee and add another short piece to the last part of the tee. You can bush down to a tubless tire valve stem and clamp it in. Now you have a system you can test with, and make repairs and retest with no problem. Submerging in the laundry tubs in your house is the easiest way to spot trouble.

    Repair:

    Heat the area leaking well with a medium propane torch, and flush/hot with Stayclean liquid Flux. Reheat the area and repair with soft solder like 50/50 or 95/5 plumbers solder, and you will have a [no worries] heater core for the life of the car. If you find there are multiple pin holes during your testing, the core is probably rotten and needs to be recored or, buy a good one from one of the Hudson guys. Bars leak, and Silver seal, or even Plain Pepper, are good, but really just a get home move, and destine to leave you overheated some day in a place you would rather not be in, if left untreated properly. Tech tip from the "old plumber", Bobby
  • ArtS
    ArtS Expert Adviser
    Thanks, Bobby, for the soldering repair advice. Anything to be warm AND dry!
This discussion has been closed.

Categories

In this Discussion