NHTSA — Engine And Engine Cooling Problems


really awful
Crashes / Fires:
0 / 1
Injuries / Deaths:
0 / 0
Average Mileage:
56,760 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2007 Hummer H3 engine problems

engine problem

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2007 Hummer H3 Owner Comments

problem #10

Dec 212014


  • 53,018 miles


Noticed radiator fluid dripping underneath vehicle. Opened the hood and found radiator coolant had been blown all over interior engine compartment. Enough coolant remained in the reservoir to prevent overheating. I noticed the incident just in time.

- Severn, MD, USA

problem #9

Oct 012014

H3 5-cyl

  • 120,000 miles
The car shut off as I was making a left hand turn with no warning or indication. Complete loss of power.

- Jacksonville, FL, USA

problem #8

Sep 112013


  • 74,000 miles
Ac/heat blower fan resistor faulty. Causes blower to stop working. The short may cause a fire. Many complaints of this issue on the internet. May be time to pursue a class action suit.

- Minneapolis, MN, USA

problem #7

Mar 142014


  • 59,614 miles


I was sitting in the line at my son's school, been sitting there 2 - 3 minutes, and I smelled coolant. Looked at my gauge and it was riding just below mid-point....normal. Got my son and started home. Sitting at the red light, I smelled coolant again. This time I knew it was my car. We went to a service station and ask if someone could check to see if we had a leak. They pulled my H3 into the back and hooked up a pressure "tool" to the radiator and low and behold, but a hairline crack on the upper driver's side of the radiator. The mechanic laughed and said I was the 2nd one this week and the 6th one since they opened 6 months ago. He said that H3S were known to have radiator issues because the radiators were plastic! seriously...plastic! I was given a quote of $1,100 to replace the radiator with another plastic one and that would give me a 2 year or 24,000 mile warranty. I brought the truck back to my house so my husband could look at it. I did some research on the internet and it seems that this is a well known problem with Hummer and yet GM has not done a recall. I found a number for Hummer customer service and called them. When I told the man that answered I had coolant leaking, he said "oh, give me your zip code and I will find a local dealership that can replace the radiator." No questions...he knew what the problem was already. He went on to say that we would have to "invest" in a diagnostic and if the dealership determined it was a manufacturers defect, that Hummer might "participate" in the repair costs. I would think with this being such a common problem, a recall would be in order and possibly a replacement radiator that isn't plastic!

- Allen, TX, USA

problem #6

Oct 292013

H3 5-cyl

  • 71,386 miles
I was driving on the express way when I noticed my engine rev real high. I looked at the RPM's and it was almost red lined. I let off the gas imediatly and came to a slow crawl and found that it would not shift out of second gear. Pulled it off the road and shut it off to get out to find that there was transmission fluid and radiator coolant pouring from the transmission. Had it towed to a mechanic to find out that the radiator was bad which caused the transmission and coolant to mix between the two. This causing the transmission to be destroyed along with the radiator. For this vehical being this low on miles this should have never happend. GM has made a faulty radiator and something needs to be done.

- Ravenna, OH, USA

problem #5

Jun 242013


  • 65,700 miles
Radiator is cracked on driver side due to rubbing of metal parts.

- Fishkill, NY, USA

problem #4

Mar 052012


  • 70,000 miles


The contact owns a 2007 Hummer H3. The contact stated that while driving approximately 20 mph, the engine stalled without warning and restarted. The failure occurred four times. The vehicle was taken to an authorized dealer for diagnosis and they were unable to duplicate or determine the cause of failure. The manufacturer was not notified of the failure. The approximate failure mileage was 70,000.

- Taylor, TX, USA

problem #3

Oct 292010

H3 5-cyl

  • 35,000 miles
Ever since I purchased this vehicle, the vehicle has stalled at between 25mph and 0. I work for the us census bureau, permanent worker and I travel through all types of weather conditions in a day, from 9,000 ft mountains covered in snow to desert gravel roads, mesas, cliffs. Over the past two years the vehicle has shut off while traversing mountain roads covered in snow with no guard rails, and three times, when the engine shut off, I lost steering and came within inches of going off the side (cliffs) of these roads, not to mention in town, when my engine shuts off as I drive, I have come close to hitting other vehicles or poles as I lose power steering on a turn.. I have to drive about 90 miles one way to get it serviced, while under warranty, I had it "repaired" about five times, no success, once warranty expired, GM dealers 90 miles away were still willing to inspect vehicle since problems started while under full GM warranty, but now, they refuse to give me a rental and tell me they do not know what the problem is. My local GM dealer (alamogordo) refuses to inspect vehicle and thus I am required to make a 180 mile round trip, but now, even dealer tells me they do not know what the issue is and they cannot reproduce the problem in the shop. I took about 6 videos with my droid after the problem happens, because the problem lingers for about 15 minutes, then it stops and the vehicle works fine. The videos how the RPM's going up and down, up and down, until the car shuts off, I restart it, then it shuts off again, over and over again. Problems usually appear in the am, as I drive off for the first time, before it is driven a good distance, but can and has happened at any moment. Very dangerous and I do not feel safe each morning as I leave my mountain home, especially in cold snow weather.

- High Rolls , NM, USA

problem #2

Aug 012007

H3 5-cyl

  • 1,884 miles
2007 Hummer H3 has vibration in the brake and accelerator pedal. The consumer also stated the vehicle overheated while driving in traffic. The consumer stated she continues to feel a kick in the pedal. The dealer was unable to fix the problems on the vehicle. Updated 01/18/11.

- Boynton Beach, FL, USA

problem #1

Mar 172009


  • 17,000 miles
I had dropped my daughter off at school then went to the gas station and I smelled something like it was burning and I thought it was out side. When I came out of the gas station there was smoke rolling out of my Hummer. I had jumped in and moved the vehicle away from the pumps so they would not blow up and hurt the patrons around us. The fire dept came and so did the police. They told me that the blow had started from behind the glove compartment and was on fire.

- Washougal, WA, USA

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