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Help with cooling/heating hoses?

Discussion in 'General Chevy & GM Tech Questions' started by Lifted_Bowtie, Dec 6, 2010.

  1. Lifted_Bowtie

    Lifted_Bowtie Member

    Okay so I was going to flush my radiator today and I noticed that there was only one hose going from the water pump to the back of the engine block... None of the hoses are connected to the firewall so I couldn't wasn't sure if I could flush the cooling system... The heater doesn't work also, should there be hoses going into the firewall to make the heater work or no? I don't know much about the heater and cooling system so any help or information you give me would be awesome.. Thanks

    This is what I'm talking about... It seems like the two hoses were clamped together...

  2. stephan

    stephan Rockstar 4 Years 5000 Posts

    Hey Bowtie, welcome to the GM truck club.

    You make it easy to diagnose your problem with the nice pic. I wish everybody put pics in here. Your heater core has been bypassed, probably by the last owner, & probably because it was leaking. Those 2 open fittings coming out of your firewall right behind your hose are for the heater core & that is where your hoses are suppose to go...
  3. Lifted_Bowtie

    Lifted_Bowtie Member

    Yep, that's what I figured after doing some research... Which hose do I use to flush my cooling system after I inspect the heater core? Wouldn't it be the one going to the block since it's an outlet?
  4. stephan

    stephan Rockstar 4 Years 5000 Posts

    I would hook up your heater core first & just run plain water in it (no flush) if you want to check it for leaks, BUT I am 99% sure it is leaking & that is why the previous owner bypassed it. There is no other reason to bypass a heater core!! You don't want a bunch of caustic flush in it since you are going to be taking the core out & you don't want that flush crap all over your hands or on your carpets.
  5. Lifted_Bowtie

    Lifted_Bowtie Member

    lol yeah im pretty sure its leaking too.. I was going to inspect it before I did any flushing because I really dont wanna clean up a mess (even just water) if its busted.. but my question now is, which hose do I use to flush? Does it matter?
  6. stephan

    stephan Rockstar 4 Years 5000 Posts

    Since your heater core is out of action, you don't need to use the heater hose to flush it. I would just leave the union in the hose as it is & put the flush in the rad. Run it according to the instructions & then pull the radiator hoses & flush the rad & engine by themselves till the water runs clear. You don't need to use the Prestone "T" in the heater hose line as that is mainly for backflushing the heater core & you aren't messing with that anyway. Also DON'T put your new heater core in before you do the flush, as that would just circulate any crap from your engine & rad. into your new core.
  7. Lifted_Bowtie

    Lifted_Bowtie Member

    Ahh i gottcha.. Thanks man, you just saved me money, time, and a lot of frustration... lol I appreciate the help.. I've already learned a lot using this site! :)
  8. stephan

    stephan Rockstar 4 Years 5000 Posts

    You're welcome Bowtie. That's why they pay us the big bucks lol
    I forgot to tell you to use your engine block drains to get the maximum effects from your flush job. There are dead spots in the block where water does not cuirculate well & a lot of sediment will be there, & if you drain this crud out, your cooling system will be a lot cleaner when you're done. I also rinse it out twice. After your first rinse, refill it with water, warm it up till the thermostat opens again, let it circulate 5 or 10 minutes & rinse it all out again.
  9. Lifted_Bowtie

    Lifted_Bowtie Member

    Engine block drains?? Huh? lol I've flushed a system before, but I've never heard about engine drains... (i feel dumb) lol but, this engine has been very neglected by the previous owner(s)... its unfortunate because the truck I traded for it (86 k5) had a spotless engine that I've seen inside and out... this one's got probably pounds of sludge in it... :(
  10. stephan

    stephan Rockstar 4 Years 5000 Posts

    Yep, they're down low on the sides of your block just about an inch above the oil pan lip. Take them out when you are draining your flush & also both times you rinse it. I have had big chunks of crud come out of these.

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