Wax as a Water Sealer?

[BrierS]

I read from the M-B Service Manual Library that wax is sprayed into channels as a sealant. What type of wax would this be and is it something that should also be used for sealing firewall/dash areas where pipes & wires go through? I am looking for advice on paint-safe sealants to use as a preventative measure for these area.
Thanks
Steve

[neileg]

In the UK we have automotive rustproofing waxes like Waxoil and Tectyl. I guess this is the type of product you need.