2004 KEYSTONE COUGAR Structure Problems

WE PURCHASED OUR 2004 KEYSTONE COUGAR TRAVEL TRAILER IN FEB 2005 FROM THE ORIGINAL OWNER WHO HAD ONLY USED IT ON A 200 MILE TRIP ONCE AS HIS WIFE HAD TAKEN ILL AND HE COULDN'T USE IT ANY LONGER. IN APR/MAY OF 2006 WE WENT ON A CROSS COUNTRY TRIP. WE HAD A BLOWOUT THE 1ST DAY OUT ON I-75 NEAR THE NORTH MARION COUNTY LINE. WE THEN HAD ANOTHER BLOWOUT AS WE ENTERED CA ON I-8. OUR 3RD BLOWOUT CAME ON OUR RETURN TRIP ON I-10 IN LA. ALL THREE TIRES WERE MISSION RADIALS THAT CAME NEW ON THE RV FROM THE MANUFACTURER AND CAUSED FENDER DAMAGE. ON MAY 31, 2007 WE AGAIN WENT ON ANOTHER CROSS COUNTRY TRIP. ON THE 1ST DAY OUT ON I-10 NEAR SPANISH FORT, AL WE AGAIN HAD A BLOW OUT OF ANOTHER MISSION RADIAL TIRE ( ORIGINAL SPARE WHICH WAS INSIDE THE GARAGE...