What is Yellow Goop Around Propane Fittings on Regulator

Updated 10/12/2026 | Published 10/07/2026

Products Featured in This Question

Thread Sealant Tape for Gas Lines

(90)

$13.24

JR Products High Pressure RV LP Gas Regulator

(166)

$24.94

Gas Pipe Sealant

(23)

$19.28

Question:

I am replacing my High Pressure RV LP Gas Regulator just purchased from you. I noticed some yellow goop around the fittings that attach to it. Do I need to use gas thread sealer or gas sealant tape on the fittings? Thanks

asked by: Larry D

Expert Reply:

Hey Larry, welcome back! The yellow material you noticed on the old regulator fittings is most likely gas-rated pipe thread sealant, and you should use fresh sealant when installing your replacement regulator if it has NPT threaded connections.

The important distinction is the type of fitting:
- NPT (tapered pipe threads): Use propane-rated thread sealant paste or yellow gas-rated PTFE tape.
- Flare or inverted-flare fittings: Do not use tape or sealant. These seal through metal-to-metal contact, not the threads.
- Propane tank connections: Do not add sealant to Type 1/ACME or POL connections; they use their own sealing surfaces.
We carry both Gas Pipe Sealant # 37207-30555 and Thread Sealant Tape for Gas Lines # 37207-30025. Either is appropriate for compatible NPT connections.

expert reply by: Jameson C