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Technical Home made cooling system tester

Discussion in 'The Hokey Ass Message Board' started by vickckik, Oct 31, 2019.

  1. vickckik
    Joined: Dec 21, 2011
    Posts: 68

    vickckik
    Member

    I need to test the cooling system for leaks, Visual inspection has not worked. If anyone has a home built tester, I would appreciate pics and description so I can make one. It's for a '62 Pontiac.
     
  2. Mr48chev
    Joined: Dec 28, 2007
    Posts: 25,936

    Mr48chev
    ALLIANCE MEMBER

    Run down to Autozone "borrow" their cooling system pressure tester, Pay the 80 something buck deposit. Go test the cooling system, get things figured out and take the tester back and get your deposit back.
    For rather spendy tools that you may use once a year or once every two or three years that works great.

    Figuring out a cap that you can put pressure to is a challenge in itself and then coming up with a pump and gauge.
     
    alanp561, 302GMC, Gman0046 and 3 others like this.
  3. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,078

    Blues4U
    Member
    from So Cal

    ...You'd also need a check valve to allow air into the system but not allow it out while pumping, or you'd never build any pressure...
     
  4. TrailerTrashToo
    Joined: Jun 20, 2018
    Posts: 450

    TrailerTrashToo
    Member

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  5. brading
    Joined: Sep 9, 2019
    Posts: 49

    brading

    Get another rad cap. Take it apart. Drill a hole in the base plate to take and fit a bolt in tyre valve stem. In the top cap make a hole that the valve stem will go through, may be necessary to add a valve extension to get long enough to come though. Assemble back on rad as it would be normally as per normal cap. Then use a foot pump with a gauge to pump up to a suitable pressure.
     
    loudbang likes this.
  6. Not trying to be a smart a**, but from how I understand the OP is that he is looking for a leak? So if the engine was warmed up, wouldn't that put the system under pressure? From the statement made, looking for a leak, it doesn't make any difference how the system is pressurized (my thoughts) you still need to "see" the leak. A pressure tester will only confirm what is already known, that a leak is present.

    I say that perhaps you should try bypassing the heater core and see if that eliminates the leak. Take a close look at the water pump weap hole. Perhaps the cylinder heads/bolts.
     
    alanp561, Cosmo50 and Texas Webb like this.
  7. oldolds
    Joined: Oct 18, 2010
    Posts: 2,811

    oldolds
    Member

    Sometimes a leak only happens when an engine is cold. It is also easier looking for a leak on a cold engine.
    I have the tool the OP needs. I would loan it to him if he was local.
     
    Randy D likes this.
  8. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 886

    Barrelnose pickup
    ALLIANCE MEMBER

    Replace the top hose with a section of motorcycle tube with the valve in place,(cut either side of the valve to the right length),pressurised to the same pressure as your cap is rated to and start checking.
    Still won’t “see” an internal leaking head gasket though.
     
  9. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 650

    Elcohaulic
    Member

    I put the hose connection in a old cap and pump the system up with a few pounds of air and listen.. This works better then running the car...
     
  10. saltflats
    Joined: Aug 14, 2007
    Posts: 9,661

    saltflats
    Member
    from Missouri

    If you have a radiator cap for a closed system, you can pump the air in through the overflow tube.
     
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  11. brading
    Joined: Sep 9, 2019
    Posts: 49

    brading

    Ya remember seeing it being done that way but with a bicycle inner tube which would nearer the outlet sizes. Cheap and easy.
     
    Barrelnose pickup likes this.
  12. The coolant dye that glows under uv light is also helpful and cheap when trying to figure out a difficult leak.
     
    alanp561 and pitman like this.
  13. vickckik
    Joined: Dec 21, 2011
    Posts: 68

    vickckik
    Member

    I appreciate the advice but don't want to buy a $80 tester for a 1 time check and Autozone does not have one to rent/loan. I'm hoping a member can post a pic of a home made tester. I know I need to incorporate a schrader valve and a pressure gauge. I just don't know how. It's a slow leak and I'll have to keep the system under pressure for quite a while in order to find the leak.
     
  14. Bird man
    Joined: Dec 28, 2009
    Posts: 479

    Bird man
    Member
    from Milwaukee

    No need to see if a '62 Pontiac is cool. WE already know that!
     
  15. RmK57
    Joined: Dec 31, 2008
    Posts: 1,170

    RmK57
    Member

    I used an air fitting and hooked it up to my compressor. Set the regulator to 20 psi and used another pressure gauge on the thermostat housing. Also used a couple expansion plugs to close off the water pump outlets. Worked great, no leaks!
     
  16. I thought about this, but wouldn't the pressure cap keep the compressed air out? The pressure cap has a spring that pushes the seal down into the opening, once the pressure inside the cooling system exceeds the cap rating, it burps. The overflow tube is "outside" of the seal, so it would not pressurize the system IMO.
     
  17. saltflats
    Joined: Aug 14, 2007
    Posts: 9,661

    saltflats
    Member
    from Missouri

    Not sure how it works, but it does. I have a small regulator set up just for this.
     
  18. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,078

    Blues4U
    Member
    from So Cal

    Just curious, but can you elaborate on that a little? Why do you think you have a slow leak? You're losing coolant somewhere? Normally you'll see evidence of coolant leaks as it will leave behind traces of antifreeze/water. At least you should be able to narrow it down. If you don't see any evidence, maybe the leak is internal, in the engine.
     
  19. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 537

    ekimneirbo
    Member
    from Brooks Ky

    When you remove the radiator cap and warm the engine up, do you see any air bubbles flowing in the coolant ? If so, do a compression check and look closely at your spark plugs for signs of a blown head gasket.

    I made some tools for pressure testing a radiator and I hook the air compressor directly to the radiator. I only use about 10 lbs as the radiator cap will release pressure if its too high. Also too much pressure may rupture something.
    You might be able to get a heater hose loose and then make an adapter to put pressure through there. Another way is to remove the thermostat housing and weld a bung and tap a fitting hole in it. Then screw an air hose fitting in it. when done, remove the fitting and screw a plug in it.
     
    Last edited: Nov 4, 2019

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