My personal experience with undercoating is that it usually causes more problems than it fixes. Nearly every installer blocked drain holes with the undercoat, causing water retention and more rust than there would have been had it all been left alone. A far better solution IMHO is to regularly wash the under side of the body during salt season and to make sure the drain holes are open.
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
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