Ive done this job on my car recently & the only issue I had was it was hard to put the upper front cover on with the cam seal already installed.It seemed much easier to put the cover on then carefully put the seal on.This way I didnt disturb the u-gasket at all.I didnt even have to lube the u-seal since the cover set on top of the gasket instead of dragging the upper cover over it.I used the factory sealant.