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coolant leak

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by KMH87K5, Jan 23, 2002.

  1. KMH87K5

    KMH87K5 Registered Member

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    If anyone ever had a similiar problem and could give me some advice, it would be greatly appreciated. The problem is that my 87 k5 350 tbi is leaking coolant from it appears the back of the motor. It seems to leak when the heat has been on and after the truck is shut off and the pressure drops, so I'm thinking it might be a heater hose. Also, the heat does not get very hot. It would be great if anyone could show me the way to tackling this problem.
    Thanks
     
  2. BigTex

    BigTex 1/2 ton status

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    Yeah, it does sound like one of your heater hoses. Check where they attach to the firewall. It may just be a small leak that you can't see.

    <font color=red>"DON'T TAKE LIFE TOO SERIOUSLY, YOU WON'T GET OUT ALIVE."</font color=red>

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  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Well hope that it isn't leaking at the back of the engine. there are no hoses back there. the only place it could leak from back there is where the heads and intake meet or where the block and heads meet.
    Most common place I have found for a leak is the heater hoses. Often the wrong size hose is used between the intake fitting and the heater core. That can cause a leak where the hose attaches to the core attaches at the fire wall or intake. If it was leaking at the intake it could run down the top of the intake and leak off the back of the block (engine it tilted to the rear). Could also be a water neck leak, collant temp sensor leak including the gage sender in the side of the heads.
    The other possiblity is a leak where the water pump joins the block and it's running around the lip of the oil pan and dripping at the rear. Need to take a close look with a good light and see if you can trace the leak and verify where it is comming from. Intake and head leaks are not very common if the parts were properly torqed when assembled so I think your going to find the sorce of the leak is somewhere else. De greasing the engine may help since you will remove any dirt and oil deposites from the engine that may hide the path the coolant is following to the low point where it is dripping. Besure to cover the distributor and throttle body with a plastic bag to prevent moiture cause ignigtion problems that sometimes happen when cleaning the engine.

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  4. sosamantx

    sosamantx 1/2 ton status

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    I'd have to agree with them somewhat. I'd wash out the engine bay area. I'd also block off the heater core and see if it still leaks. hopefully it's not a freeze plug on the back of the head??

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  5. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Dupe post - guess I stuttered.......<P ID="edit"><FONT class="small">Edited by 96C4and91K5 on 01/23/02 10:38 AM.</FONT></P>
     
  6. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    The heater doesn't get hot?

    Have you had your radiator out for cleaning and flow testing?

    If you have high miles and no cooling system maintenance you might be in need of a major overhaul. But it is very easy and relatively low $$ for parts (rad recore or new, heater core)
    and it is DIY.

    I had my rad rebuilt cuz they can do stuff like reinforce the inlet and outlet tubes internally.

    Clean and check as much as you can - that doesn't hurt and I'll cross my fingers that it is not coming from elsewhere.

    Dave

    Rehab is for quitters.
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  7. Mudstud

    Mudstud 1/2 ton status

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  8. Mudstud

    Mudstud 1/2 ton status

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  9. 2Dogs

    2Dogs 1/2 ton status Premium Member

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