Fuel filler neck grommet.
Dimensions: 50mm outside diameter, 38mm inside diameter.
Fits: 1983-91 Vanagon 2WD & 4WD - with plastic filler neck.
Have a steel filler neck? Get the 251-201-139 grommet.
On install, be sure the inner lip is in place by feeling around the seal. You may feel a bump or small distortion meaning the grommet is not seated properly and needs adjusting.