My buddy has a 90 Legacy LS sedan that had a cooland leak, I thought it was the lower radiator hose so I bought him a new OEM hose, and tonight he went to put it on, and discovered that it wasn't the lower hose, but a smaller hose that connects to a metal line that runs up to the top of the block, over the top of the block, and then to a rubber hose that connects to the heater core. I can find the heater hoses in the catalog at 1stsubaruparts.com but I can't find the hose he needs, which is the small one that is under the motor next to the lower water inlet... HE was thinking of just replacing it with a piece of hose from the parts store, but it looks like it's a molded hose... Any suggestions?

I don't think using an unformed hose would be a big deal, as long as it doesn't make any kinks in it or anything.

When I needed heater hoses for my 99, the Subaru dealer could not get them, out of stock for months. I got a full set perfect for the car at my NAPA parts store in one day, and for less. If you don't have NAPA, call every store in your area, somebody may stock correct aftermarket parts. As I recall, there was a short 90 degree bend hose at the water pump, two heater hoses which went from metal tubes on the driver side rear of engine to firewall, and two hot water hoses to throttle body, one from each metal tube. The throttle body hoses were nearly impossible to access without removing the intake manifold.

The p/n for this hose is 807615081. It's a bypass hose, but don't know what it's called in the catalog.

When I went to NAPA, I think they sold me 5/16" heater hose for this application after measuring what I brought in. As 86BRATMAN mentioned, as long as it doesn't kink or leak it should be fine. The risk of course with this item not working is icing of the intake butterfly.

 

Here's a pic of one I got for I think my '00obw (7.6mm is .299 inches, closest match is 5/16" which is .3125 inches)