2003 Hummer H2 Engine cooling Problems
- Complaints
- 5about this part
- Share
- 4%of 141 total for the year
- Median mileage
- 80,000miles
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 5 complaints about the engine cooling of the 2003 Hummer H2, 4% of the 141 complaints for this model year. Where a mileage was given, the median is 80,000 miles.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“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?”
NHTSA complaint #10417752, filed 2011-08, 80,000 miles“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.”
NHTSA complaint #10207993, filed 2007-11, 80,000 miles“I bought a 2003 Hummer H2 brand new. Since the day I got it had many problems, both electrical and mechanical. The steering is very hard and the breaking is ineffective at times. I showed them a copy of the bulletin on this website. They did not acknowledge any problems. The issue still persists. Many electrical issues seat memory problems, mirror don't work..etc. Eventually the electrical issues fixed. Roof leaking water from the reading light on two occasions once because of sunroof issue and the second time because of the outside roof light. …”
NHTSA complaint #10140896, filed 2005-10Related service bulletins
- 10251890Mar 13, 2024This technical bulletin advises of a new fuel injection cleaner kit used for decarbonizing the intake valves to correct conditions of rough idle, Crank no start, extended crank…
- 10250775Feb 22, 2024This service bulletin provides service information to technicians on guidelines to replace Oil Cooler, Oil Cooler Lines and Oil Tank if the engine was replaced where large…
- 10249579Jan 12, 2024This PI bulletin advises the technician on the proper way to install the pistons in an engine.
- 10242262Aug 24, 2023This service bulletin provides graphics, information and guidelines for engine component wear to assist service personnel as a guideline to perform necessary engine repairs and…
- 10240344Jul 31, 2023This service bulletin explains how to measure for oil consumption and possible reasons for loss of oil.
- 10236164Apr 24, 2023This Preliminary information communicates information that will need to be provided to TAC to aid in diagnosing if a vehicle comes in with misfire and DTC Codes P0300 - P0308…
- 10235802Apr 24, 2023This diagnostic tip bulletin provides additional information on how to diagnose a possible valve, lifter or camshaft issue.
- 10234141Mar 23, 2023This diagnostic tip bulletin provides additional information on how to diagnose a possible valve, lifter or camshaft issue.
- 10234110Mar 17, 2023This service bulletin provides service information on new torque specification and installation procedure for ACDelco Spin-On Oil Filters.
- 10227056Nov 9, 2022This service bulletin provides service information to technicians on guidelines to replace Oil Cooler, Oil Cooler Lines and Oil Tank if the engine was replaced where large…
Engine cooling: other model years
Other parts of the 2003 Hummer H2
52 complaintsElectrical system
24 complaintsBrakes
18 complaintsSteering
17 complaintsBody and structure
13 complaintsSuspension
11 complaintsTransmission and drivetrain
11 complaintsSeats
5 complaintsWheels
5 complaintsEngine
4 complaintsVehicle speed control
3 complaintsFuel system
2 complaints
← All problems reported for the 2003 Hummer H2
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 27, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology