Metric Port Plug M8 x 1.0

Swapping a turbo, changing a coolant routing or removing a sensor almost always leaves a small metric port that has to be sealed. Vibrant's 16658 plugs an M8 x 1.0 threaded port, a size common on turbocharger housings, coolant and oil galleries, fuel rails and sensor bosses on many import engines. It is machined from 6061 aluminum and black anodized, and it comes with its own crush washer.

How It Seals

This plug seals on the crush washer, not on the threads. The soft washer sits between the underside of the plug head and the flat spot-face around the port, and as you tighten the plug the washer deforms slightly to fill any imperfections in the surface. That is why thread tape or liquid sealant is not needed, and why it is worth using a fresh washer any time the plug comes out.

Specifications

• Part number: Vibrant 16658
• Thread: M8 x 1.0 metric
• Material: 6061 aluminum, black anodized
• Includes: one crush washer

Installation Tips

Confirm the port is M8 x 1.0 with a thread gauge before ordering, because M8 x 1.25 is also common and will not thread in properly. Clean the sealing face around the port, install the plug by hand, then snug it with a wrench just enough to crush the washer. Aluminum threads strip easily, so avoid overtightening.

Frequently Asked Questions

Should the threads get sealant?

No. The crush washer makes the seal. Sealant on the threads can actually keep the plug from seating fully against the washer.

Is the crush washer reusable?

It is best to use a new washer each time the plug is removed, since a crushed washer will not seal as reliably a second time.

What about an M8 x 1.25 port?

It will not fit. This plug is M8 x 1.0 fine thread only, so check the port with a thread gauge first.

Fitment: Universal. Confirm the sizes and thread types listed above against your application before ordering.