NHTSA Complaint #726533 — 2000 VOLVO S80

INTERMITTENT PROBLEM, 2 OCCURRENCES. CONDITIONS AT LATEST OCCURRENCE: DRY PAVEMENT, AIR CONDITIONER ON, STEADY 65MPH, TWO PEOPLE IN CAR. SYMPTOMS: NOTICED HUMMING SOUND THAT GOT LOUDER AND TRANSITIONED INTO SIGNIFICANT RAPID VIBRATION OF ENTIRE CAR. STEERING WHEEL VIBRATED (NOT OSCILLATED) 1/32 TO 1/16 INCH. TRIED ACCELERATING, VERY SLUGGISH RESPONSE AND WHEN CAR DOWNSHIFTED VIBRATION DID NOT CHANGE. APPLIED BRAKES AND EXPERIENCED SIGNIFICANTLY INCREASED VIBRATION ESPECIALLY IN FRONT END AND PEDAL. VIBRATION WAS NOT PULSATING LIKE ANTILOCK BRAKES BUT RATHER LIKE WHEELS OSCILLATING. STOPPED AND INSPECTED WHEELS AND TIRES-APPEARED NORMAL. PROBLEM DID NOT REOCCUR WHEN I RESUMED DRIVING. DEALER CHECKED CAR AND DID NOT FIND ANYTHING WRONG.*AK