06 Hummer H3 random exhaust smoke

20

Asked by Oct 01, 2015 at 01:14 PM about the 2006 Hummer H3 4dr SUV 4WD

Question type: Maintenance & Repair

When I run the car for over 25 minutes, and let it sit for an hour, I get smoke out the exhaust pipe.  If I drive it short distances and let it sit, it does not done this.  My coolant level is fine. It seems very inconsistent, as I have driven over 100 miles, and then when I start it, it is fine.
5 speed manual

6 Answers

94,955

If it is oil smoke the valve seals could be bad. If you live in a humid climate that is just about enough time for condensation to build up in the exhaust system so you will see it for a short time.

1 of 1 people found this helpful.
930

Sounds like either the piston oil rings or the cylinder head valve guides are beginning to fail and allow oil to mix in with the air and gas, hence the smoking exhaust. Try adding Wynn's Engine Restore to your oil plus and Oil Treament, as short-term fixes. At some point you'll need to rebuild or replace that engine.

1 of 1 people found this helpful.
20

it isn't burning oil or coolant, that is what I cannot figure out.

2 of 2 people found this helpful.
930

If its smoking it's either burning oil or anti-freeze, there is nothing else it could be burning and then releasing from the exhaust pipe, sorry. Now it could be moisture in the exhaust that's evaporating as the exhaust slows heats up and vaporizes any moisture. Driving it would then remove any moisture from the exhaust and then it won't do it again. Common for vehicles that are not driven much. These vehicles tend to have the exhaust system rot form the inside out due to the build-up of moisture and rusting. Burning anti-freeze is a white exhaust smoke with a sweet or sticky odor. Burning oil has a grey/black/dark and heavy exhaust. Leaking brake fluid would have smoke pouring out from the front engine compartment, unless theres a leak in a brake line somewhere. Get it properly checked out.

1 of 1 people found this helpful.
20

my coolant level isn't really changing beyond normal. it is white smoke, could it be a small leak in the gasket? it is definitely not oil.

930

A coolant leak will emit white smoke and smell sickly sweet, an oil leak will emit a grey smoke and smell heavy to the nose. Measure and track your fluid levels carefully each time the same way from the same spot, then monitor them for a few weeks to see if there's any change. Even a small coolant leak will show after a long period of time. But if the exhaust is white, or foggy, and has no foul odor, then it's probably just moisture from inside the exhaust getting heated-up and turning into condensation. This is normal for a vehicle stored after use. Cooling metal will sweat and the surrounding air will release moisture and build on the metal, just the same way a window fogs-up and is sometimes inside a house when the outside is cold or very humid. A leaking head gasket must be caught before it causes permanent damage. Try performing a few cylinder compression leak tests over a long period of time and track the results. Early 90's Chevrolet Cavaliers had defective metal shim head gaskets that leaked coolant into only 1 cylinder head. Sometimes they seal themselves over time and the head and block surfaces warp and mate better, and sometimes they leak more. In cases like this there's no immediate solution but to watch, monitor and track the results over time and then you've got something to help you identify the real problem if there is one. Ever vehicle I've ever owned did this same white exhaust at times. In every case except 1 it's just been moisture in the exhaust system, with 1 case being the head gasket. In 1 different case the valve cover gasket was leaking oil down the back of the engine block and sometimes would end-up on the exhaust, but again, oil produces a thick grey smoke. Good luck.

1 of 1 people found this helpful.

Your Answer

Add photo

Related Questions

  • 06 Hummer H3 random exhaust smoke 6 answers

    When I run the car for over 25 minutes, and let it sit for an hour, I get smoke out the exhaust pipe. If I drive it short distances and let it sit, it does not done this. My coolant level is fine. I...

    2006 Hummer H3 4dr SUV 4WD

    -

    Maintenance & Repair

  • My 06 H3 Hummer won't after it rain or washed 2 answers

    I've been having a lot of electrical problems with my H3 Hummer 2006 everytime it rains or I take the car and get a wash it will not crank up I don't know what's wrong with it I've tried everything...

    2006 Hummer H3 4dr SUV 4WD

    -

    Maintenance & Repair

  • Hummer H3 2 answers

    My hummer h3 gets stuck when I turn the steering wheel almost all the way like when I need to back up and turn to pull out or to just take a sharp turn to drive in to a parking it slowly comes to...

    2006 Hummer H3 4dr SUV 4WD

    -

    Maintenance & Repair

  • 2008 hummer h3 2 answers

    My 2008 h3 hummer i have replaced the alternator an battery there both good u can shut the vehicle off when u go to start it up it plays dead hook jumper cables up it jumps right off im really lost...

    2008 Hummer H3 Base

    -

    Maintenance & Repair

  • Scan tool for H3 Hummer 2 answers

    I am looking for a scan tool that will read H3 Hummer error codes on the ABS, Traction control and Stabilitrack. I have been told that the Equus 3130 scan tool will work ok on the H3 Hummer.

    2007 Hummer H3 4 Dr Base

    -

    Maintenance & Repair

H3

Looking for a Used H3 in your area?

CarGurus has 1,885 nationwide H3 listings starting at $5,488.

ZIP:

Search Hummer H3 Questions

Hummer H3 Experts

#1 cocod
cocod
Reputation 800
#2 HummerGirl
HummerGirl
Reputation 760
#3 PatriciaDoss
PatriciaDoss
Reputation 560
View All

Related Models For Sale

Used Hummer H2
31 Great Deals out of 1,283 listings starting at $7,900
Used Hummer H2 SUT
8 Great Deals out of 257 listings starting at $12,995
Used Jeep Wrangler
260 Great Deals out of 16,543 listings starting at $2,590
Used Jeep Wrangler Unlimited
278 Great Deals out of 40,652 listings starting at $10,500
Used Ford F-150
2,058 Great Deals out of 207,340 listings starting at $1,499
Used Chevrolet Tahoe
559 Great Deals out of 31,371 listings starting at $1,500
Used Jeep Grand Cherokee
1,027 Great Deals out of 72,252 listings starting at $700
Used Toyota 4Runner
260 Great Deals out of 19,021 listings starting at $2,500
Used Chevrolet Silverado 1500
1,764 Great Deals out of 181,202 listings starting at $250
Used Toyota FJ Cruiser
79 Great Deals out of 2,251 listings starting at $6,995
Used Ford Mustang
543 Great Deals out of 45,845 listings starting at $1,999
Used Dodge Charger
454 Great Deals out of 29,324 listings starting at $2,300

Used Cars For Sale

2006 Hummer H3 4dr SUV 4WD For Sale
26 Great Deals out of 698 listings starting at $5,488

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.