Engineering Analysis EA08-022: TIRE VALVE OZONE CRACKING

BY LETTER DATED DECEMBER 5, 2008, DILL SUBMITTED A REPORT TO ODI IDENTIFYING A DEFECT RELATED TO OZONE CRACKING IN TWO PRODUCTION LOTS OF TIRE VALVE STEMS THAT WERE MANUFACTURED IN CHINA BY TOPSEAL AUTO-PARTSIN JULY 2006 (NHTSA SAFETY RECALL NO. 08T-028).

ACCORDING TO DILL, APPROXIMATELY 1,800,000 VALVES WERE DISTRIBUTED AND SOLD IN THE UNITED STATES FROM THE SUBJECT LOTS.DILL ESTIMATES THAT ABOUT 200,000 OF THESE VALVES MAY BE PRONE TO OZONE CRACKING RESULTING IN TIRE AIR LOSS DURING THEIR EXPECTED SERVICE LIFE.TIRE VALVE FAILURE COULD RESULT IN SUDDEN LOSS OF VEHICLE CONTROL AND POSSIBLY A CRASH. DILL BASED THIS RANGE ON ITS ANALYSIS OF CLAIM DATA, WHICH SHOWED THAT THE VAST MAJORITY OF VALVES RETURNED FROM THE FIELD WITH CRACKS SEVERE ENOUGH TO HAVE LEAKED AIR WERE INSTALLED FROM NOVEMBER 2006 THROUGH JULY 2007.

FOLLOWING A FREE INSPECTION,DILL VALVES THAT ARE CRACKED WILL BE REPLACED UNDER THE RECALL FREE OF CHARGE.DILL HAS ISSUED A PRESS RELEASE PROVIDING INFORMATION ABOUT THE RECALL AND HAS POSTED INFORMATION FOR CONSUMERS ON THE INTERNET AT WWW.TIREVALVERECALL.NET.EA08-022 WAS OPENED BY ODI ON SEPTEMBER 23, 2008, TO INVESTIGATE APPROXIMATELY 23,450,000 VALVES MANUFACTURED BY TOPSEAL FROM JULY 2006 TO NOVEMBER 15, 2006.

DURING THIS PERIOD, TOPSEAL CHANGED ITS SUPPLIER OF THE VALVE RUBBER COMPOUND USED FOR OZONE PROTECTION .IN A MAY 2, 2008 CUSTOMER ADVISORY LETTER TO COMPANIES THAT PURCHASED THE SUSPECT VALVES, DILL DESCRIBED THE SCOPE OF THE POTENTIAL PROBLEM AND INDICATED THAT IT MAY AFFECT VALVES SHIPPED BY DILL FROM LATE-AUGUST 2006 THROUGH MID-FEBRUARY 2007.

DILL ALSO REQUESTED THAT ITS CUSTOMERS:(1) INSPECT ALL UNUSED INVENTORY AND RETURN ALL BOXES WITH LOT NUMBERS FROM 2006; (2) INSPECT THE VALVE STEMS ON ALL VEHICLES THAT RECEIVED VALVE STEMS IN THE PERIOD FROM SEPTEMBER 2006 THROUGH JUNE 2007, AND (3)REPLACE ANY VALVES WITH VISIBLE SURFACE CRACKS.SAMPLES OF UNUSED VALVES RETURNED TO DILL IN RESPONSE TO THIS ADVISORY WERE SELECTED FROM EACH PRODUCTION LOT. DILL SENT THESE VALVES TO AN INDEPENDENT LABORATORY TO CONDUCT RUBBER CHEMISTRY AND OZONE RESISTANCE TESTING (SAE J1205/1206).

DILL ALSO MAINTAINED A CLAIM LOG TO RECORD INFORMATION ABOUT CRACKED VALVES REPLACED IN INSPECTION PROGRAMS.IN AN OCTOBER 2, 2008 LETTER TO ODI, DILL SUMMARIZED ITS ASSESSMENT OF VALVE TESTING AND CLAIM DATA ANALYSIS.DILL INDICATED THAT TWO PRODUCTION LOTS FROM JULY 2006, LOTS L AND B, WERE FOUND TO HAVE BEEN COMPOUNDED DIFFERENTLY THAN OTHER VALVES FROM THE BROADER PRODUCTION RANGE IDENTIFIED IN DILL'S MAY 2, 2008 CUSTOMER ADVISORY LETTER.DILL INDICATED THAT VALVES FROM LOTS L AND B FAILED OZONE AGING TESTS AT A HIGH RATE AND LOT B SAMPLES WERE THE ONLY VALVES THAT, AFTER OZONE TESTING, EXHIBITED CRACKS SIMILAR IN SEVERITY TO THOSE OBSERVED IN FIELD RETURNS. ODI NOTES THAT DUE TO THE LACK OF TRACEABILITY OF VALVES AFTER THEY ARE REMOVED FROM SHIPPING BOXES, IT IS NOT POSSIBLE TO DETERMINE CONCLUSIVELY THE MANUFACTURING DATE OR LOT NUMBER OF DILL VALVES INSTALLED ON VEHICLES OR WHAT PORTION OF VALVE CLAIMS ARE ASSOCIATED WITH THE TWO LOTS IDENTIFIED BY DILL.IT IS POSSIBLE THAT SOME VALVES FROM THE SUSPECT LOTS WERE SOLD OUTSIDE THE RECALL RANGE AND THAT OTHER LOTS MAY ALSO BE SUSCEPTIBLE TO OZONE CRACKING.HOWEVER, ODI'S ANALYSIS OF CLAIMS DATA SUBMITTED BY DILL SHOWS THAT, REGARDLESS OF THE LOT OR MANUFACTURING DATE, APPROXIMATELY 92 PERCENT OF RETURNED DILL VALVES WITH CRACKS SEVERE ENOUGH TO LEAK AIR WERE INSTALLED DURING THE PERIOD COVERED BY THE RECALL.MOREOVER, DILL IS NOT REQUIRING CONSUMERS TO PRODUCE RECORDS PROVING THEY HAD TIRE VALVE STEMS INSTALLED DURING THE DESIGNATED MON […]