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Heater hose connector failure.


Well-Known Member
Bellflower, CA
So I almost had a $45,000 failure the other day. I just got home from work and I had steam rolling out from under the hood of my 01 Silverado. So as I was letting it cool down I grabbed a beer and started to ponder the Colorado Diesel. After the engine cooled down I started to look for where the coolant was coming from. It was from the top of the engine at the back, I checked the oil and it was fine, no milky mess. Ah, I might be lucky and not blown the motor and just blew a manifold gasket. Upon further inspection, I noticed the heater core hose was loose. Sure enough, the cheap plastic connector that is between the hose and the metal tube for the core had fallen apart. Luckily the replacement parts and tool to remove the connector was $12 on Amazon. So if it is good enough for the Silverado it must be good enough for every other GM vehicle right? Sure enough, my H3 has the same plastic connector but a crimped hose instead of barbed and clamped. So if the H2's are kissing cousins to the Silverados you guys may want to check your heater hose connections.
Plastic fitting just fell apart when I tried to remove it with a needle nose.

The connectors on my Silverado.

The connectors on the H3.


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Well-Known Member
Northeast Pennsyltucky
It made it out of the warranty period, so it must be perfectly designed. Unfortunately, there are lots of plastic/rubber parts that turn to dust over time.


Well-Known Member
I just replaced some plastic heater hose fittings on my 99 Burb (220k miles). Same deal...intermittent leak coming from passenger side of engine bay. The Burb has front and rear heat so there are "t" fittings in the heat circuit, and also a 4-port heater control valve....all made of plastic.
So I made the mistake of touching one of the t-fittings and KA-BLOOEY...the fitting crumbled and emptied the cooling system in my driveway.
A week after I replaced it...I get the telltale smell of coolant again. Now the plastic control valve is crumbling (no doubt I disturbed it when replacing the t-fitting)....so ordered a new one and this time I replaced the other t-fitting as well. Now all the old plastic is gone and I should be good for another 200k miles. My hoses all had worm-gear clamps...made back before GM went to hell.