[KTL]

theiceman mentioned the best test I know of- the softness/squish test. If the hose is still soft and you can squish it somewhat easily with your hand, it's still in good shape. Also look for surface cracking when you do the squish test. I've found a handful of originals over the years that are rock hard just like he describes. I also am guilty of saving old S-hoses that are still in decent shape and squishy. I guess I just don't have a lot of faith in newer stuff.

But also look for over-tightened hose clamps. If the previous installer gorilla tightened the clamps, you may find cracking next to the clamps.

This hose is under negative pressure since it's a suction hose. The pipe under the oil cooler is a direct connection to the inlet side of the oil pump. So these hoses typically leak when the engine is not running and the weight of the oil sitting in the oil tank tries to sneak out.