Water/coolant leaking from unknown area

yukon
#1

Apparently I have a leak in truck but the confusing part is, it’s leaking from the rear somewhere above my tailpipe and right rear wheel.

One day on my way to work my truck all of a sudden starts overheating. I checked my oil, oil is good. Checked my coolant, coolant was low but not low enough to force an overheat. Still I fill it with water and go on about my work day.

When I got home later that evening, note that I overheated on the way home also, I noticed that my eat was low again. Double checked again and assured myself it wasn’t mixing with my oil.

So then I proceed to water to my reservoir again and immediately noticed the water running from what I thought was my tailpipe until I tried to get a closer look…not my tailpipe but somewhere above. Is there a hose or something I’m not aware of back there. Haven’t had the time to take my truck to get looked at, and rather not try to drive it. Also, if it’s a easy fix I rather not pay $100 for someone to tell me.

Anyone ever heard or know anything about this??

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#2

What is your truck? Make, model, year, engine, mileage?

Coolant is going somewhere, clearly. You have a leak.

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#3

Is there are heater core back there, in addition to the one in the lower front dashboard area?

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#4

My guess is coolant is leaking through a head gasket, into the cylinders then the exhaust, traveling to the muffler; and out a weep hole.

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#5

2004 GMC Yukon 230,000

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#6

Since it is a SUV, if equipped with a rear HVAC unit, that may very well be the source. Hose or core leaking. The HVAC is in the right rear.

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#7

Me thinks you’re going to have to spend the $100. Head gasket as mentioned or there may be some frost plugs back there that have rusted out. Not a fun job. Take a closer look crawling on top of the engine with a good light and mirror and take a look around.

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#8

Sounds like the auxiliary heater (rear) or the plumbing to it is leaking. Drive without coolant and the head gaskets with be the next thing to fail.

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#9

Yeah good catch “by the rear wheel”. Of course water leaks are elusive so you start where you see the leak and move up to find the source. A lot easier if its on a lift.

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