cause the valve to fail. Air leaks can also cause oil aeration, foaming, marginal lubrication, and premature engine wear. Care should be taken to make sure all parts on the suction side of the pump fit tightly and there is no place for air leakage. Air leakage often comes from cracked seams in the pickup tube.On integral pumps, the timing case and gear thrust plate might be worn also. Wear here will limit pump efficiency due to excess clearance. Replace them as necessary.