There are 3 owner-reported engine complaints for the 2005 Hummer H2in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
VEHICLE HAS 133,000 MILES. IT HAS NOW EXPERIENCED AN EXHAUST MANIFOLD GASKET LEAK DUE TO BROKEN BOLTS. THIS IS CAUSING NOISE FROM THE ENGINE AREA, AND IS UNSAFE DUE TO THE LEAK OF HOT GASES BEING RELEASED FROM THE ENGINE AT THE POINTS OF FAILURE (BROKEN BOLTS). THIS MAY BE AN EPA CONCERN AS WELL, AND COULD ALSO LEAD TO FAILURE OF CATALYTIC CONVERTER. REPAIR ESTIMATE IS $1,300. AN ONLINE SEARCH YIELDS HUNDREDS OF OTHER RESULTS WITH SAME FAILURE AND COMPLAINT ON ALL GM V8 ENGINES FOR YEARS 1999-2007. THIS AFFECTS THE 4.8L, 5.3L, AND 6.0L MODELS. THIS IS A DESIGN FAILURE AND THE AFFECTED VEHICLES WITH THESE ENGINES SHOULD BE RECALLED.
MY VEHICLE'S WARRANTY WHICH I PURCHASED SEPARATELY HAD JUST EXPIRED BUT I STILL WENT BACK TO DEALER AS THE NOISE I HAD REPORTED TO THEM UNDER WARRANTY WAS NOW MORE APPARENT. TURNS OUT IT WAS DUE TO BROKEN OFF EXHAUST HEADER BOLTS.NOW I AM OUT OF WARRANTY, DEALERSHIP WILL NOT FIX. I HAVE 1 BROKEN ON DRIVERS SIDE AND 3 ON PASSENGER SIDE. NOW MY CHECK ENGINE LIGHT IS ON SHOWING AN OXYGEN SENSOR FAILURE OR CATALYTIC CONVERTER. AFTER RESEARCHING THE INTERNET THIS PROBLEM IS AFFECTING THOUSANDS OF PEOPLE. SOMETHING NEEDS TO BE ADDRESSED !! *TR
TRANSMISSION COOLER DEFECT ALLOWS GLYCOL TO ENTER TRANSMISSION. TRANSMISSION OVERHEAT CONDITION OCCURS FILLING THE INSIDE OF THE VEHICLE WITH A TOXIC GAS. HOT TRANSMISSIONS CAN ALSO CATCH ON FIRE. THIS IS A KNOWN CONDITION; GM ISSUED AN ALERT TO DEALERSHIP SERVICE DEPARTMENTS BUT NO RECALL HAS OCCURRED. *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026