There are 4 owner-reported engine complaints for the 2009 Hummer H3in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
The contact owns a 2009 Hummer H3. The contact stated that while attempting to start the vehicle, the vehicle failed to start. The contact waited for a while before the vehicle started. The contact stated that the vehicle was slow to start. The contact stated that while her husband was at the store, he waited for 15 minutes before the vehicle started. There were no warning lights illuminated. The vehicle was taken to an independent mechanic who replaced the battery and starter, but the failure recurred. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was unknown.
TL* THE CONTACT OWNS A 2009 HUMMER H3. WHILE THE CONTACT'S SON WAS DRIVING APPROXIMATELY 60 MPH, THE VEHICLE LOST POWER WITHOUT WARNING. THE VEHICLE WAS PULLED TO THE SIDE OF THE ROAD AND TURNED OFF. THE VEHICLE RESTARTED AFTER A COUPLE OF ATTEMPTS. THE VEHICLE WAS TAKEN TO A LOCAL DEALER WHERE IT WAS DIAGNOSED THAT THERE WAS ENGINE AILURE. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE, BUT DID NOT OFFER ANY ASSISTANCE. THE FAILURE MILEAGE WAS 107,000.
THE VEHICLE WAS PURCHASED USED @ 36954 MILES. APPROXIMATELY A YEAR LATER (JUST 2 DAYS AGO) @ ONLY 53500 MILES I NOTICED AN ANTIFREEZE SMELL. NO VISIBLE PUDDLE UNDERNEATH. AFTER MONITORING FOR 1 DAY MORE POPPED THE HOOD THIS MORNING AND A BIT OF ANTIFREEZE SEEMS TO BE SPRAYING FROM THE TOP OF THE RADIATOR. AFTER JUST GOOGLING ONCE FOR "HUMMER H3 RADIATOR LEAK" THE TOP LINK LEADS TO HUMMERFORUMS.COM IN WHICH IS LOGGED MANY MANY MANY OWNERS GOING BACK SEVERAL YEARS UP THE THE PRESENT HAVING THE EXACT SAME ISSUE. PER WHAT IS DESCRIBED ON THE 52 PAGES DEDICATED TO THIS ONE THREAD AND FROM WHAT I SEE ON MY OWN VEHICLE THIS CERTAINLY SEEMS TO BE A DESIGN/ENGINEERING FLAW. IT SEEMS A RARE FEW DEALERSHIPS ARE OWNING UP TO THIS "FLAW" AND CHARGING A SMALL AMOUNT IF ANY TO REPAIR THIS ISSUE WHILE OTHERS ARE PLEADING IGNORANCE/INNOCENCE AND MAKING THE PLETHORA OF CUSTOMERS EAT THE NEARLY $800 DEALERSHIP REPAIR ESTIMATE. THE FLAW APPEARS TO BE RELATED TO METAL CHASSIS PARTS RUBBING ON THE PLASTIC RADIATOR TOP CREATING A HOLE AND A VIBRATORY EFFECT WEAKENING THAT PLASTIC CAUSING A CRACK.
AT APPROXIMATELY 49,000 MILE MARK, VEHICLE STARTED TO MAKE UNUSUAL ENGINE NOISE IE. GROAN, CLICKING, USUALLY BETWEEN 10-20MPH, WOULD DISAPPEAR,THEN RETURNED BETWEEN 30-40MPH AND DISAPPEAR AGAIN AT HIGHER SPEEDS. TOOK THE VEHICLE IN A TOTAL OF FOUR TIMES TO DEALER. FIRST TIME, THEY SAID IT WAS THE FRONT BRAKES/ROTORS, COST $120. NOISE STILL THERE. SECOND TIME, THEY SAID IT WAS THE FRONT SHOCKS (COVERED BY WARRANTY BUT PART NOT IN STOCK HAVE TO RTN A THIRD TIME). THIRD TIME, THEY REPLACED FRONT SHOCKS(COVERED BY WARRANTY), NOISE STILL THERE. FORTH TIME, STATED IT WAS THE ENGINE MOUNTS AND TWO HEAT SHIELD (ALSO COVERED BY WARRANTY). NOISE IS STILL THERE BUT VERY FAINT IF YOU LISTEN CLOSELY. DEALER SAYS THEY CANT DO ANYTHING ELSE AND AGREE NOISE IS NOT SUPPOSE TO BE THERE. WILL WAIT ANOTHER FEW MONTHS UNTIL VEHICLE IS DUE TO BE RTN AT END OF LEASE TERM. THANK GOODNESS. *JS
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