AutoPlumb Adapter Assembly Instructions

Before You Begin:
Watch our adapter assembly video for step-by-step guidance.

Tools & Materials Needed:

• Strap wrench

• AN wrench

• Permatex Ultra Black Gasket Maker or equivalent silicone adhesive (must be adhesive-type gasket maker; DO NOT use regular silicone)

Note: Silicone adhesive is not used as a sealant—it acts as a lubricant to help the seal fully engage the taper during assembly. Once cured, it adds strength and rigidity.

 

Assembly Instructions

1. Disassemble the adapter.

2. Apply the Assembly Tape.
   Viewed from the back, wrap clockwise 

3. Measure the water neck.
   From the back of the bead to the face should measure 5/16” or less. Trim if needed.

4. Clean the water neck thoroughly.

5. Install the adapter ring
   

6. Lubricate the shim.
   Apply a light film of grease and coil it onto the water neck.

7. Apply silicone adhesive.
   Coat the entire rubber seal generously. Slide it onto the water neck with the chamfer facing outward. Spread any excess silicone around the outer edge of the seal.

8. Attach the adapter body.
   Lubricate its threads. Hold it squarely against the water neck and hand-tighten the ring. Then, tighten fully using a strap wrench and AN wrench. The ring should sit flush or within 0.075” of the adapter body.

9. Clean up.
   Use lacquer thinner if needed. Ensure everything is aligned and let it set for several hours—ideally overnight.

After curing, the adapter will be firmly attached but remains removable and reusable.

Important Note:

When tightening or loosening hose ends, always support the adapter with a wrench. Do not overtighten. Re-check connections after the engine warms up.

 

Special Instructions:

Water Necks Without a Bead/Barb:

• • A bead is recommended but not required. If removed, the installer assumes all risk.

  • A minimum of 1” neck length is required for safe installation.

  • This procedure has proven to be safe and effective. There have been no reported failures.

Modified Installation:

• • • Push the seal past the end of the water neck, leaving ~3/8” exposed.

    • Apply a generous bead of silicone in front of the seal to act as a stopper.

    • Proceed with the rest of the installation as described above.

    • Make sure the adapter is square and Do not disturb for 24 hours.

LS Water Pumps:

• • Most LS water pumps have two beads.

  • For clearance and cleaner appearance, remove the outer bead only. Cut squarely up to the second bead, leaving no more than 5/16” from the back of the bead to the face.

-20AN Hose End Assembly:

• • Watch the -20AN hose assembly video

  • Use AN aluminum vise jaws and a proper AN wrench to avoid damage.

  • Place the sleeve against the vise jaws at the thickest point.

  • Use a heat gun near the end of the process to make tightening easier and prevent damage.

Barb Adapter Assembly:

• • You may need to shave down the barb OD to fit the hexed ring.

  • Install the hexed ring and O-ring over the barb.

  • Liberally apply Permatex Ultra Black Silicone Adhesive.

  • Assemble and let cure for 24 hours.

 

Need More Assistance?
Call us at: 405-823-7149