heater core tubes

Joined
Jul 24, 2024
Messages
5
Hi All,

Ive been a lurker here for years. you guys always seem very meticulous and knowledgeable, so i figured id actually post.

Working on the MILs 2000 Yukon. pulled the intake manifold and of course, when i put it back on, i bumped the closest heater hose quick connect tee and snapped off the 24 year old line.

Bought a metal disconnect tool, but i dont think it engaged long enough to move the QD fingers out of the way. Seeing as how plastic connector was broken, i used some needlenose pliers to try to help pull the old broken connector off while pushing with the QD tool from the back.

Finally got the carcass of the old plastic tee off, but now looking at it, the needlenose pliers were pulling/wiggling on the aluminum heater core tube too.

Its not obviously loose, but whats the chances that i loosened up the heater core tube press/crimp/solder/whatever thats holding it to the core?
If i leave it alone, will it be obvious to see drips or worse?

Im now worried that ill be replacing the heater core itself (looks like real fun from the videos i saw).

talked to the parts man and he says the tubes are pressed into the core.

thoughts?

thanks all!
 
Put it back together and do a pressure test.

Everything is pressed on these days.

You can bypass the heater code if you busted something on it. Until winter of course.
 
the only reason i havent put it back together is those horrible quick disconnects. the tool i have must be wrong.

I wonder if i can just cap the line that runs to the rear heater and just run rubber heater hose, double clamped for the pressure test?

thanks!
 
I rarely replace GMT800 heater cores....As much as people mess with the quick connects, You'd think core failures would be more common if it were a weak link.

GM used a couple different designs over the years.....The closed style that requires a tool, And the open 2 Tab style.

The best tool I've found for the closed style is OTC 6046, I doesn't last forever.....I go though a couple a year. I have a Aluminum one from AST & doesn't work as well.

On the open 2 tab style, I take a long cabinet style flatblade screwdriver & break off the 2 plastic strips ahead of the lock tabs. Yeah.....You gotta break the connector apart so you can rotate the connector to access both tabs (Only an issue with rear heat SUV's)
 
I bought a dorman equivalent of OTC 6046. broke that in about 10 minutes. got the metal one.
But, i was unaware of 2 designs. i definitely have the 2 tabs and did everything i could think of to squeeze them. thats why i thought i needed this tool. But, lining the tool up with the replacement QD connector, its just not long enough to pull those fingers back.

Is there a reason i cant just get a brass tee and some rubber heater hose and make this thing serviceable for another 250k miles? I havent complained about GM like this for at least 5 years. This thing had me inventing words.
 
You can't slip a hose past the "barb" on the heater core lines.....I say can't but I'm sure people have, You will damage the reinforcement strands in hoses doing this.

Clamping just on the ends of the lines/tubes can lead to a hose blowing off.

I use genuine GM tees & connectors, They last 15-20 years usually.
 
Im sure this isnt the approved tool but it worked pretty well pressing the connector tabs when I had to replace my Tee. Harbor Freight is your friend here.
38969E34-8E9C-43CE-83A6-807E7139926D.jpeg
 
Im sure this isnt the approved tool but it worked pretty well pressing the connector tabs when I had to replace my Tee. Harbor Freight is your friend here. View attachment 232053
yes, those look like they might work. i found a 90 degree bend long reach needlenose that might be useful too. for 15 bucks, im sure ill need it at some point. i pulled the tee side off (goes to the back heater core) and cleaned things up, so im ready to reassemble and pressure test.

thanks guys
 
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