One problem related to engine knocking noise has been reported for the 2001 Subaru Forester. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Subaru Forester based on all problems reported for the 2001 Forester.
I was driving down the freeway at night when I heard a loud bang noise and looked behind me and saw black smoke and had lost all power, no power steering, no brakes and no lights I had to try to cross 2 lanes of traffic to get my car to the shoulder while it was decelerating. I got the car to the shoulder and noticed smoke coming from the engine compartment, and was worried of a possible fire. I got out and called a tow truck and had it towed. The result was a blown head gasket that had blown the rod through the back pillar and sprayed oil over everything causing the battery to short out which led to the power loss. The whole engine on the car needed to be replaced for the second time. Bought car with a rebuilt engine from same problem at 141,000 miles.