engine making ticking noise

my mom has a 2003 pontiac montana thats making a ticking noise says its low on oil but i just changed the oil 2 and half weeks ago i just need help trying to figure out why it would be ticking

Have you checked the oil level? Did it make this noise before the oil change?

I didn't know they had an oil level indicator

Ticking from an engine can be related to many issues. First I suspect a lifter. Lifters can tick for many miles with no adverse affects on the engine. If you changed the oil recently the I would make sure the oil level is good. Use the dipstick to determine if you have the right amount of oil, make sure the van is level when checking it. I also am assuming that you changed the oil filter as well. If not then you may be suffering from an oil issue related to a blocked or partially blocked filter. Also did you use the proper weight of oil specified in the owners manual. An oil that is too thick can cause ticking issues in an engine.

I hope this helps!