Caps and Plugs

Every plumbing job leaves a few ports you do not need, and the right plug or cap seals them without leaks. This collection covers the Vibrant Performance and ARB caps and plugs in AN flare, NPT pipe thread, ORB and metric thread styles, including low profile hex head and socket head designs.

AN flare caps and plugs

AN caps thread over a male flare and AN plugs thread into a female fitting to close off a line or a fitting during testing, storage or a phased build. They seal on the 37 degree flare just like a hose end.

NPT, ORB and metric port plugs

NPT plugs seal tapered pipe ports with thread sealant. ORB plugs carry an O-ring and seal against a spot face, and metric plugs come with crush washers for factory engine and transmission ports. Socket head and low profile hex plugs fit in tight spots where a standard hex head will not clear.

Plastic caps for storage

Plastic caps and plugs keep dirt out of open fittings and lines while a car is apart, which protects pumps, injectors and turbos from debris during assembly.

Common questions

Do I use thread sealant on ORB plugs? No. The O-ring does the sealing. Sealant can actually keep the O-ring from seating.

What sealant should I use on NPT plugs? Use a paste or tape rated for the fluid in the system, and keep it off the first thread so it cannot get into the system.

Can an AN plug hold full system pressure? Yes. AN plugs and caps are rated for the same pressures as the fittings they seal.

What's in This Collection

  • 61 products from Vibrant Performance and ARB, priced from $3.29 to $26.50
  • AN sizes: -3, -4, -6, -8, -10, -12, -16, -20
  • Free shipping on orders over $150

How to Choose

Start with the hose or line size, then the port you are connecting to. AN sizes run in sixteenths of an inch, so -6 AN is 6/16 or 3/8 inch, -8 AN is 1/2 inch and -10 AN is 5/8 inch. Then match the other end: AN flare, NPT pipe thread, ORB with an O-ring, or metric. Pick the angle that points the line where it needs to go without a tight bend right at the fitting.

More Questions

Do AN fittings need thread sealant?

No. AN fittings seal on the 37 degree flare, so sealant on the flare or threads is not needed. Only tapered NPT threads need a sealant.

What is the difference between AN and ORB?

AN fittings seal on a 37 degree flare. ORB fittings use straight threads and seal with an O-ring at the base of the thread, which makes them very leak resistant in ports.