Hugo ---

Last month I bought a 1987 Vanagon with a rod knock.  The prev_owner had
taken it to a Jiffy Lube, where they crossthreaded the drain plug.  Then he
took it to a mechanic, who put in a helicoil, but may have treated the chip
problem too lightly.  Not long afterwards, the engine developed a rod
knock...... perhaps from metal chips, or from the control-label filter used
at Jiffy Lube??  Would you want this scenario??

On the other hand, if you know the folks who work at the Firestone and they
let you supply the filter, and they let you replace the drain plug, then
maybe it's worth doing.