A heat exchanger assembly having a manifold, a partition member inserted into the interior cavity of the manifold through an open end such that the partition member cooperates with the interior surface of the manifold to partition the interior cavity into a manifold chamber and a distributor/collector chamber. The partition member and distributor/collector chamber function together as a distributor/collector tube within the manifold. The partition member includes a plurality of orifices along a length of the partition member, two opposite facing flange portions along the length of the partition member, a bulkhead panel extending from an end of the partition member adjacent the open end of the manifold, and a spring locator tab panel extending from an end of the partition member opposite of the bulk head panel, wherein the spring locator tab panel is biased against the closed end.