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Your Mom Goes To College
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Discussion Starter · #1 ·
Woke up yesterday, saw coolant leaking from what seemed to be the front of the engine. I took it to a repair shop, and they did a pressure test on it. The cap was faulty, so they replaced it. I am 95% sure I have a blocked heater core, as the "in" hose to the core gets hot, but the exit hose does not. Also, I have no heat. Pressure test found no other leaks.

I drove it around all day yesterday, no leaks, but when I parked it overnight, it started leaking again, but only when it the engine was cold.

Any clue as to what is going on here?

1998 Chevy Blazer, 2wd, 116,xxx miles. New radiator, new intake gasket.
 

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goin broke but n style
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i have seen hoses do this, water pumps, radiators, t-stat housings.

pressure test the cooling system when truck is cold.
 

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Sometimes I'm mean...alot
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It's because of the the Dex-Coool that your heater core is clogged with goop....disconnect both heater hoses and use water pressure to try and dislodge/flush the crap out of the heater core. Try one way, then the other until you get it to flow clear..
 

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Your Mom Goes To College
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749 Posts
Discussion Starter · #4 ·
Went to bypass the heater core, outlet hose was FILLED full of crap. Just full of crap.

Anyways, the bypass was successful, but I forgot to ask, will those plastic hose connectors be ok or will they melt? Particularly the piece that goes inside of the 2 hoses.
 

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goin broke but n style
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they will be ok if they are designed for coolant. just some regular vac hose connections will not take the temps very well.
 

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Your Mom Goes To College
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Discussion Starter · #6 ·
they will be ok if they are designed for coolant. just some regular vac hose connections will not take the temps very well.

haha I think it was for a garden hose. I have a copper one too, maybe I should go ahead and switch them out.
 

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Sometimes I'm mean...alot
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Went to bypass the heater core, outlet hose was FILLED full of crap. Just full of crap.

Anyways, the bypass was successful, but I forgot to ask, will those plastic hose connectors be ok or will they melt? Particularly the piece that goes inside of the 2 hoses.
Why by-pass when you can back flush it with a garden hose and reconnect it?
 

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Your Mom Goes To College
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Discussion Starter · #8 ·
Why by-pass when you can back flush it with a garden hose and reconnect it?
I will do that this weekend, this was more of a quick-fix to get me through the rest of the week until I could get around to it.

Woke up this morning, huge puddle under the truck. Where in the hell could this be coming from?

Does NOT leak while under pressure. Heater core bypassed. Brand new cap put on.
 

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Your Mom Goes To College
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749 Posts
Discussion Starter · #10 ·
LIM or UIM gasket. My truck would have a pool under it overnight because as the motor heated it would expand and seal the LIM. When cool, it would contract and drip right out.

LIM's usually go 70,000-90,000 miles. If yours is at 116,000, it's probably time to do it.
I just had one of them replaced about 5 months ago, probably the UIM. Second time I had it replaced. That was a good $700.

I'm not going to spend that much again to fix a truck that would barely get that off trade in, and I no longer have the time to do these things myself.
 

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Your Mom Goes To College
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Discussion Starter · #12 ·
find a buddy that will help you get it done quick

or take it back to where you got it done. The fact that it's leaking after 5 months is bogus. Check your UIM for cracks.

Most gaskets have a 1 year warranty. make em do it again.
I just moved to a state that doesn't have the same auto repair place where I got it fixed.

What luck.
 

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whats wrong with teal?
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i had a similar issue after being parked it would leak turned out to be my water pump by the weep hole only after it cooled would it leak
 

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Next spring on my 4.3 2000 Sonoma I'm replacing the intake manifold gaskets and new water pump and hoses.
Anything else I should replace while I'm at it? This is a very clean one owner truck with only 70 k miles on it.

Scott
 

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Slowly but eventually
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Yeah, I also had a radiator do the same thing. It was leaking around where the plastic tank and the metal core were joined. It started out leaking only when it was cooled off, but then got worse.

I also agree with the water pump though, as both of mine have done the same thing.
 

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i had a similar issue after being parked it would leak turned out to be my water pump by the weep hole only after it cooled would it leak
Definitely verify that the leak is not from the water pump. I also experienced a similar situation where coolant was leaking from the water pump weep hole while parked only. Or rather, the leak was no worse while driving. (I did not spend much time trying to determine how the leak changed while parked vs. driving as it was obvious, in my case, that the water pump had failed)
 
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