norco team xc

Have a new 05 Quest with about 6000 km on it and the spray on undercoating/insulation/rust proofing has fallen off. Yes fallen off. Peeled like old paint. It was a semi soft rubber compound that helped to deaden the sound. Van is now very noisy on the highway especially in the rain with the bare wheel wells. Anyone else have this problem? Nissan has suggested "Rust Check" which solves the rust proofing problem not the noise level in the van. Anyhelp is appreciated.
Thanks