on my daughters 2008 hhr coming out of the heatercore the hoses are 2 different sizes but but the other end the inlets coming off the engine are the same size. which one conncts where they had the hoses off before i got there and i have not a clue

 

It would help to know which engine she has.

 

But, the hose end i.d.'s should be reasonably close to the fitting sizes.