on a 91 ls the lower hose that connects to the thermostat and the head is called what?

 

bbaallliinnnn

 

If it is one of the smaller diameter hoses and shaped like a big 'U', its called a 'bypass hose', costs around $4 from the dealer. I replaced all my little hoses with generic hose from the auto parts store cut to length, but since this particular hose has a sharp bend, the generic hoses would kink. So I bought this particular 'bypass hose' from the dealer.

Number 3 maybe
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