Air carrier First Officer reported descending below the glide slope on approach to MMMX; in part due to selecting Level Change mode of the FMC.

Narrative

Enaga3A arrival that joined up to the ILS Y 05R MMMX. We were vectored off of the arrival a couple of times and given altitudes to descend to and then were cleared back on to the arrival and were cleared for the ILS Y 05R. PF selected Level Change to descend while off of the arrival and when we were cleared back on the arrival and cleared for the approach Level Change was the mode still selected. Once inside MX960 Touchdown Zone was set. Once on the final approach course and in VMC with the runway in sight I noticed that we seemed to be lower than I would have expected to be on final at this point. My eyes immediately went to the Mode Control Panel and I verified with the Flight Mode Annunciator (FMA) that we were not in APP mode and I verbalized to the PF that we were still in Level Change; would you like for me to arm the approach for you; and he said yes. At this point we both had the runway in sight and were below the glide slope. The PF immediately corrected by leveling off and capturing the glide path from below.