13. An older engine that uses flat-bottom lifters should have an
adequate amount/number of in its oil or oil-additive.
A. viscosity
B. ZDDP (zinc)
C. diesters
D. polyalpholefin (POA)

Respuesta :

Answer:b ZDDP (zinc)

Explanation:Most engine and engine component manufacturers recommend zinc and phosphorus content of more than 1,200 PPM for break-in; in fact, many will void warranties on camshafts or crate engines if this minimum is not found in the oil sample you supply when returning broken parts for warranty.