bluiewest1
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- May 31, 2011
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Recently replaced heater core on 92 Sierra with a 4.3L. The combination (part rubber, part aluminum) coolant line that attaches to a quick release (HA!) fitting on the right rear of the intake manifold, was leaking at the fitting. The rubber portion had deteriorated and would develop holes inboard of the clamp at the heater core inlet. Tried to buy new coolant line and discovered that it is a dealer only part.
Attempted to remove aluminum end from quick release and couldn't get it to budge. Then tried to unscrew entire fitting and the POS broke off almost flush with the intake manifold!
Dorman makes a tool to extract the stem (must be a common problem), but it didn't do anything other than make the center hole bigger. Don't waste your money on one.
Ended up using a small chisel and a pick to carefully clean out as much of the broken off stem as I could see. The quick release fitting is installed in the intake minifold at an angle and you can't really see the portion of the opening toward the centerline of the intake. The fitting is made of zinc, pot metal or some other crap and it fragments fairly easily.
Used a 1/2 inch NPT (national pipe thread) tap to retap hole in intake manifold. Had to use a socket, short extension and rachet handle to be able to put some downward pressure on the tap as well as turn it. Not enough room for a regular tap handle.
Be sure to oil the tap every half turn or so and also run tap in until all the the cutting threads are in the hole. I'm told that NPT fittings are tapered and I initially did not run the tap far enough in and I couldn't get the replacement fitting seated.
I used a plain old threaded nipple (Dorman part # 56237) in place of that POS quick release and also eliminated the dealer only combination coolant line. One additional hose clamp and 24" of 3/4 OD rubber hose finished the job!
Attempted to remove aluminum end from quick release and couldn't get it to budge. Then tried to unscrew entire fitting and the POS broke off almost flush with the intake manifold!
Dorman makes a tool to extract the stem (must be a common problem), but it didn't do anything other than make the center hole bigger. Don't waste your money on one.
Ended up using a small chisel and a pick to carefully clean out as much of the broken off stem as I could see. The quick release fitting is installed in the intake minifold at an angle and you can't really see the portion of the opening toward the centerline of the intake. The fitting is made of zinc, pot metal or some other crap and it fragments fairly easily.
Used a 1/2 inch NPT (national pipe thread) tap to retap hole in intake manifold. Had to use a socket, short extension and rachet handle to be able to put some downward pressure on the tap as well as turn it. Not enough room for a regular tap handle.
Be sure to oil the tap every half turn or so and also run tap in until all the the cutting threads are in the hole. I'm told that NPT fittings are tapered and I initially did not run the tap far enough in and I couldn't get the replacement fitting seated.
I used a plain old threaded nipple (Dorman part # 56237) in place of that POS quick release and also eliminated the dealer only combination coolant line. One additional hose clamp and 24" of 3/4 OD rubber hose finished the job!