Car Problem Reports

Hummer H3 Worn Valve Seats May Cause Engine Misfire

 
Hummer H3 Problem
29 Reports
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Model Years Affected: 2006, 2007, 2008

Engine Affected: 3.7L 5 Cylinder

Average Mileage: 66,746 mi (33,456 mi - 115,300 mi)

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The engine may develop a misfire due to worn valve seats. This fault will cause the Check Engine Light to illuminate. Replacement of the cylinder head may be required to correct this concern.

  • Visitor, , 3.7L 5 Cylinder, 41,000 mi

    Dealer had to replace heads...still under warranty... if it was not it would be big $$$...Gm should do a recall !!!

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  • Visitor, , 3.7L 5 Cylinder, 82,500 mi

    Engine light came on; 2 months after warranty expired, so brought it to dealer and found cylinder 5 pressure was low and need a new head....$2657 later it's as good as new. GM WHERE IS THE RECALL!!!

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  • Visitor, , 60,000 mi

    Rough idle, cylinder head is bad, just out of warranty. Shame on GM.

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  •  Rookie

    Same rough idle & check engine light on. Took to dealership under warranty, they said misfire on #5 cylinder & need to replace head. They said it is a common problem with H3. One year later, same problem. Have to take to dealership again. GM NEEDS TO DO A RECALL TO PERMANENTLY FIX IT!!! ITS RIDICULOUS IF THEY ALREADY KNOW ITS A PROBLEM!! I am thinking of getting rid of the vehicle after its fixed because I only have one more year of warranty left & its ashame because the vehicle is very good with no other problems ever with it.

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  • Visitor, , 3.7L 5 Cylinder, 40,666 mi

    I first noticed an intermittent rough idle when starting the engine while cold. The rpms would hesitate then drop suddenly to below 500 before jumping up to around 1100 and normalizing without any other issues while running. As it started to happen more frequently, I brought it to the dealer and was told that there was no check engine light and they weren't able to recreate the problem. I brought it in twice more and had the throttle body and injectors cleaned before catching a rough start on cell phone video and brought it to the dealer for the fourth time. They advised me that the check engine light should have been lit, but never came on and there was a misfire trouble code. The service report said that there was an "erratic misfire on cylinders 1-4 and a consistent misfire in cylinder 5". They compression tested the #5 cylinder and found the pressure was low due to "leaking exhaust gases". The cylinder head was replaced in accordance with service bulletins and thankfully under warranty.

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  • Visitor, , 33,456 mi

    Engine light illuminated several times over a 2 week period. Initailly, dealer suggested that I check the fuel cap and\or purchase fuel from a "different" station. However, neither of the suggestions solved the problem. Major work (replace head) was required on vehicle. Dealer estimates it will take at least a week to fix it. On a good note: it's under warranty!!

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  • Visitor, , 57,000 mi

    bad cylinder head, soft valve seats

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  • Visitor, , 94,500 mi

    2006 # MIS FIRE CODE
    RUNS GREAT BUT I CANT PASS SMOG MY MECHANIC SAID POSSIBLE LEAKY VALVE ..SO RIGHT NOW I HAVE IT AT THE DEALERSHIP .. WAITING FOR THE CALL TO LET ME KNOW WHAT THE PROBLEM IS..I WILL REPORT BACK

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  • Coach127, , 3.7L 5 Cylinder, 43,550 mi
     Rookie

    Check engine light keeps coming on. Have had it on machine twice both times show recent engine misfire. the second time it pin pointed #5 cylinder.Mechanic switched #4 coil and plug with #5 problem still in #5 cylinder. Problem is still in #5

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  •  Rookie

    rough idle, in shop now, tech says code shows seepage in cylinder, doing a leak test now.

    Final report: bad head. Just out of warranty. Cost: $2335 to replace.

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