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  1. #1

    Default Water leaking under Suburban

    I have a 1996 Suburban 5.7. I started noticing water under the passenger side last week. It seems to vary between a LOT of water and just a very small pool. I can see it dripping down under the front passenger seat/behind the tire. The interior is completely dry. No AC, just been using heat. I also noticed the last few days that I can hear sizzling after I park, sounds like something is dripping and hitting something hot on the passenger side, toward the firewall, under the hood. My coolant is still fine, I'll go check again today, but as of a couple days ago it was still just peachy (I checked after there was a massive amount of water under the car). I also threw a code today, I'll hook up the OBD reader in a bit (I had one about a month ago as well, but it was just an emissions issue) and check what it is too, maybe that'll give me some insight, who knows.

    Any ideas? I'm reading things about seals/gaskets/cracked heads, but its coming from back behind the engine, on the passenger side, I don't see any liquid on or near the engine, so I don't *think* its that? I'm not a car person, but my husband is, so feel free to throw technical stuff at me, lol.

    Edit: Checked again and now the coolant is low so that is a possibility. It doesn't smell like coolant has to have gone somewhere. I took pics as well.

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    Last edited by Cari; 12-18-2012 at 08:11 AM.

  2. #2


    I would go borrow a pressure tester from a autoparts store and test the system. If you pump it up to 16psi you should find your leak rather quickly. As of now, I would stop reading things about heads, gaskets, and so on. It will just scare you into thinking your problem may be worse than what it is. While the above things are a possibility, It could be as simple as a hose clamp or a cracked hose. A pressure test will let you know if it is something simple. I just looked at your pictures. It could be one of the hoses that carry coolant to the rear heating unit.

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  3. #3


    Thank you. No worries about me freaking out prematurely, I'm under the assumption that it isn't anything major, I just don't want to ignore a problem and then find out it was something serious and cause more damage than necessary. A hose sounds likely, especially since I'm actually seeing the coolant levels go down now. I think if we'd seen that happening to begin with it wouldn't have been a question, but seeing all the water under there with the coolant levels still being fine seemed very odd. Now to check the code.

  4. #4
    Master Mechanic silverhobey's Avatar
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    Oct 2010
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    I have seen rear frost plugs open up a little ...this would cause slow usage of the
    coolant as well. We had this happen personally, but it blew the plug right out. The
    cost to fix was minimal, and was about a 5 minute job because the engine frost plug was
    easy to get at.

    Good luck with whatever u find Brian
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  5. #5


    I have been known to do a ton of research about an issue with my truck. I of course always find the worst case scenario and insist that it must be that. Then, when I look at the actual issue I have been lucky enough that it has been something simple. Let us know what code you have.

  6. #6


    Alright, code was just the same thing, so nothing to do with this. Reservoir is almost empty but the radiator is full and not leaking at all, so hubby is thinking the reservoir itself has a leak. Hopefully that's all it is, easy fix

  7. #7


    Good to here. Easy fix. I would pressure test it to be sure prior to buying the new reservoir.

  8. #8
    Jr. Mechanic dfhollums's Avatar
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    Sep 2009
    Elmore, Elmore Co., AL


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    My wife has a 1999 Chevrolet Suburban and on two different occasions I noticed coolant leaking in the same location. I ended up tracing the leaks to two different plastic tees that various heater hoses connect to, refer to #13 and #14 in the picture of the cooling diagram. Now, this diagram is for the 1999 model, I don't know if the 1996 model is similar or not and I don't want to give you any wrong information. I do hope this helps in some way though.
    Last edited by dfhollums; 01-01-2013 at 10:03 PM.

  9. #9


    Just replaced those fittings on a friends 99 Suburban along with the heater control valve. One of the tees was shaped like a y. We had to get that at the dealer for about $12. The other parts were purchased at Pep Boys for less than $20.

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