There are 6 owner-reported engine complaints for the 2003 Hummer H2in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
A PARKED HUMMER H2 2003 WAS SPONTANEOUSLY COMBUSTED AND DESTROYED. THE SUV WAS DRIVEN THAT FATEFUL DAY FOR ABOUT 15 MINUTES BACK AND FORTH TO A GROCERY STORE AND PARKED IN OUR DRIVEWAY. ENGINE WAS OFF AND KEY WAS OUT. ABOUT 10 MINUTES LATER, MY DAUGHTER NOTICED THE ENGINE ON FIRE AND PANICKED. CALLED 911. FIRE ENGINE HOSED THE FIRE OUT IN THE NEXT 1/2 HOUR BUT THE SUV WAS CHARRED AND THE FRONT OF THE HOUSE DAMAGED BADLY. WE HAD KEPT THE H2 WELL MAINTAINED AND SERVICED IT REGULARLY. THERE WERE NO MECHANICAL OR ELECTRICAL ISSUES OTHERWISE. WE ARE A NON-SMOKING FAMILY. VERY SAD TO SEE OUR PRIDE AND JOY BURNT TO ASHES. MY FAMILY COULD HAVE BEEN BADLY HURT. PLEASE INVESTIGATE SO OTHERS COULD BE SAVED FROM THE CATASTROPHE WE ARE GOING THROUGH. *TR
I WAS DRIVING THE TRUCK AND IT TURNED OFF. *TR
EXHAUST MANIFOLD BOLTS RUSTED OFF AND THE VEHICLE MAKES A TICKING SOUND. I JUST OBSERVED A VIDEO EXPLAINING THAT THIS IS A COMMON PROBLEM. IT ALSO MAY CAUSE OTHER EMISSIONS RELATED PROBLEMS. CALL ME DAY OR NIGHT FOR ANY FURTHER INFORMATION. THIS VEHICLE HAS HAD NOTHING BUT PROBLEMS AND AN UNRELATED ENGINE FIRE DUE TO THE FAULTY WINDSHIELD WIPER MOTOR IN 2009. *TR
I HAVE A 2003 HUMMER H2, AND I HAVE A FEW BROKEN BOLTS ON MY EXHAUST MANIFOLDS. I'VE LEARNED THAT THIS IS A PROBLEM WITH THESE ENGINES THROUGH ONLINE RESEARCH. ALSO I HAD TO REPLACE MY CATALYTIC'S BECAUSE OF THIS ISSUE. MY MECHANIC HAS TOLD ME THAT THIS IS A VERY EXPENSIVE REPAIR, CAN ANYONE HELP ME? *TT
2003 HUMMER H2 TRANSMISSION COOLER RUPTURED WHICH LEAKED TRANSMISSION FLUID INTO ENGINE COOLANT. REQUIRED REPLACEMENT OF RADIATOR, ALL COOLANT HOSES AND FLUSHING BOTH THE TRANSMISSION FLUID AND ENGINE COOLANT. COST WAS $1,400. UNKNOWN IF TRANSMISSION WAS DAMAGED FROM CONTAMINATION OF FLUID. *TR
ENGINE OVERHEATING WITH H2 HUMMER, STRANDED ON ROADSIDE 100+ TEMP. *NM
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 25, 2026