PATTERSON, Calif. (AP) _ A teen-age girl's body is rejecting a heart received from a classmate who died suddenly in 1986, days after telling his parents he wanted his beloved to have his heart, her father says.

Doctors are seeking another heart to replace the one donated to 17-year-old Donna Ashlock by Feliz Garza Jr. in 1986, her father, Ray Ashlock, said in interview at their home in this farming town 90 miles from San Francisco.

Garza, a 15-year-old high school admirer, knew Donna had a degenerative heart disease and told his parents he wanted his heart donated to her when he died. Days later, he died of a cerebral hemorrhage.

''In 5 to 10 percent of the (transplant) cases, there is chronic rejection,'' said Nancy Millhouse, a spokeswoman at San Francisco's Pacific Presbyterian Medical Center, where the transplant occurred.

''She's been through a lot and she's handled herself well,'' Ms. Millhouse said of the girl.

Donna, who will turn 18 on April 1, said she is anxious to get a new heart.