by the outside looks of a hose. It can look to be in very good condition on the outside but literally rotting away on the inside.
One OEM, 9yr old heater hose split down the middle today, replaced both heater hoses while I was there - an extremely painstaking job as you are literally plastered up against the firewall with no-where to go, can't see the bottom hose clamps, and have to pretty much go by feel.
These hoses, aside from the one splitting, looked otherwise in perfect condition - which is why I believe my mechanic didn't change them out.
I'm here to tell you, that they WERE completely rotted on the inside and could have caused a major break-down this summer for sure - because don't expect your local Napa, Autozone, Checker or Advanced Auto to carry these two hoses, they were dealer items only. At least in my town.
If anyone has any hoses, heater or radiator over 6yrs old, be cautious and be gone with them.
BTW - the two heater hoses are not cheap, either, one is $45, the other is $66 and you'll need about 3/4 gallon of antifreeze. The OEM clamps that are on these hoses are a BI%#$ to remove! Don't wish this one on anybody.