2004 Chevrolet Trailblazer EXT Problems

What owners report

Owners of this model year most often write about the instrument cluster: speedometer, tachometer, fuel and oil-pressure gauges that stick, spike or quit while driving. Complaints also cover fuel-system smells and leaks, intermittent low beams, and a few transmission and exhaust-manifold concerns. Reports appear from roughly 40,000 miles upward, with many in the 50,000-90,000 mile range.

1. 1
   Electrical system

   Instrument cluster gauges fail or read wrong

   • 135 complaints (52%)
   • median 62,321 mi at 5.4 yrs old (113 state mileage)
   • owner-quoted repair $525 (median of 16 quotes)
   • filed 2006–2017

   Owners describe the speedometer, tachometer and other gauges sticking, spiking, reading far above actual speed, or dropping to zero, sometimes one gauge at a time and sometimes the whole cluster. Several say the problem comes and goes, more noticeable after using cruise control, and that the dealer could not duplicate it or quoted a cluster replacement costing several hundred dollars. A few report warning lights flashing along with the gauge faults. Mostly reported between about 40,000 and 90,000 miles, with some at higher mileage and some intermittent for weeks before becoming constant.

   3 related service bulletins

   What to check: On a test drive, watch whether the speedometer and tachometer move smoothly and settle to zero when stopped, and compare the speedometer against a GPS. Ask whether the cluster has ever been repaired or replaced.

   2 excerpts from owner complaints in NHTSA records

   “Speedometer was reading 90mph on a trip and cars were passing me, when I stopped the speedometer read 35mph standing still. It did this for about 3 days, then went back to normal. The other day coming home from a trip it seemed like it was acting up again, but my husband was driving, he thought it was acting up too. It is back to normal, haven't done anything about it.”

   NHTSA complaint #10393751, filed 2011-03, 90,000 miles

   “Several times that I've been driving the trailblazer, the speedometer goes crazy and says that we are traveling at a much higher rate of speed than we are. Like if im going approx 70mph, it states we are going about 110mph! This is definitely a safety issue! And it has never been a recall?”

   NHTSA complaint #10254346, filed 2009-01, 42,000 miles
2. 2
   Engine cooling

   Stalling, hard starting or loss of power

   • 38 complaints (15%)
   • median 51,717 mi at 5.1 yrs old (28 state mileage)
   • 1 mention a crash, fire or injury
   • filed 2005–2018

   Owners report the engine stalling at stops or in traffic, sometimes restarting only after several minutes, and dealers resetting the computer or being unable to isolate the cause. A few describe rough running, extended crank or a reduced-power message, and one notes a fuel injection valve fault after the vehicle shut down repeatedly. Reported from very low mileage up to roughly 160,000 miles, often intermittent and without stored codes.

   2 related service bulletins

   What to check: Ask whether the vehicle has ever stalled or needed long cranking, whether the throttle body and intake have been cleaned, and take a test drive that includes idling in traffic and a cold start.

   2 excerpts from owner complaints in NHTSA records

   “Check engine light - for over one year now, and 4 various mechanics, no once can figure out why my check engine light comes on. I have replaced two air sensors (actually 3 - one was bad)... I have spent close to $1,000 to get this fixed - but the dam light continues to go on (intermittently) sometimes it's on for a month - off a day - on two weeks - there is no pattern. The last time the light came on, my car began stalling in traffic and stop signs. Last mechanic spent 5 hours tracing all the codes back - nothing. …”

   NHTSA complaint #10354710, filed 2010-09, 120,000 miles

   “I purchased a Chevrolet ext trailblazer on nov. 26, 2004. 2 months later on feb. 1, 2005 it was towed into the dealership after shutting down 5 times with 2 loud explosions. The malfuction of the vehicle came close to a couple of accidents occuring and an almost near death experience for my daugher and I when it shut down for on a 4 lane highway by attempting to cross it unto the residential area. The dealership informed me that the fuel injection valve had malfuctioned and remained open releasing all the gasoline unto the engine. …”

   NHTSA complaint #10108442, filed 2005-02, 5,000 miles
3. 3
   Fuel system

   Gas smell or fuel leak after filling

   • 44 complaints (17%)
   • median 83,000 mi at 7.2 yrs old (35 state mileage)
   • owner-quoted repair $973 (median of 8 quotes)
   • filed 2005–2019

   Owners report a strong gasoline smell after filling the tank or a visible fuel leak, often traced by dealers to a cracked filler neck or a leak at the top of the tank. Some describe the service engine soon light coming on with an EVAP small-leak code first and mention that replacing the gas cap did not help. One complaint describes fuel pouring from the underside of the vehicle with a full tank. Reported from about 60,000 to 165,000 miles, usually after refueling or with a full or nearly full tank.

   2 related service bulletins

   What to check: Fill the tank before buying and smell for raw fuel around the filler area and under the rear; ask whether the filler neck or tank has been replaced and whether an EVAP leak code has been stored.

   2 excerpts from owner complaints in NHTSA records

   “Several months the smell of gasoline was very strong in the interior of my SUV. I drove it about five miles from my home with a full tank, as I drove it the smell became much strong, when I reached my destination a person pointed out to me that gasoline was pouring from the bottom of my truck like a water hose. I immediately returned home to park the vehicle. …”

   NHTSA complaint #10535221, filed 2013-08, 165,454 miles

   “Service engine soon light came on. Took it to auto zone and computer diagnosis was evap emission leak, small. Code:p0440. This happened twice over 2-3 week period. Replaced gas cap, that was not the problem. Light came back on. Took to dealership garage, I was told that I had a significant leak in my gas tank, at the filler neck, would cost $900 to fix it. Thing is, I had been driving this car around for over 3 weeks with my 2 small children in it with the possibility it could have caught on fire! How scary is that? …”

   NHTSA complaint #10247244, filed 2008-10, 85,000 miles
4. 4
   Exterior lighting

   Low-beam headlights cut out intermittently

   • 14 complaints (5%)
   • median 74,000 mi at 6.9 yrs old (11 state mileage)
   • 1 mention a crash, fire or injury
   • filed 2005–2018

   Owners describe the low beams going dark without warning while driving at night, while high beams and other lights keep working, and say the lights come back on after a while or after restarting. Several mention that no codes are stored and that shops could not find the fault. One owner also reports low beams blinking in cold weather until the vehicle warms up. Reported across a wide range, from about 24,000 to 167,000 miles, often at night and in cold conditions.

   Recall 04V5270002 related service bulletins

   What to check: Check the low beams at night and note whether they flicker or dim, and look for signs of bulb-socket or connector heat damage; ask whether the lamps or wiring have been serviced.

   2 excerpts from owner complaints in NHTSA records

   “When driving the headlights all of a sudden just shut off. It is extremely scary at night. I found that I can however use the brights. They eventually come back on. This has been happening for years. I kept hoping for a recall and just found this site to report it. This has happen on city streets and highways. It has happened when there are street lights and vehicle lights and when it is pitch black. The 1st time it happened, I was driving with my child in the vehicle on the freeway.”

   NHTSA complaint #11074267, filed 2018-02, 40,000 miles

   “Starting june 17, 2008, the low beams on my 2004 Chevrolet trail blazer lt go out intermittently - the high beams, fog lights, hazard lights, and turn signal lights still work - only low beams causing problems. I keep my lights setting in the postion that they come on when I start my car. I consider this a safety factor. The lights will go out suddenly. I can only document one time that they went out during the day time, but have documented seven (7) times that the lights went off at night. …”

   NHTSA complaint #10237497, filed 2008-08, 44,000 miles
5. 5
   Engine cooling

   Cracked or leaking exhaust manifold

   Mentioned in 4 of 60 sampled complaints

   Owners describe a ticking noise from the engine that shops diagnosed as a cracked exhaust manifold, with one reporting an exhaust leak found at an oil change and a replacement cost around a few hundred dollars. One complaint explains the manifold bolts coming loose, the manifold then cracking before repair. Reported around 62,000 to 89,000 miles in the sample.

   3 related service bulletins

   What to check: Listen for a ticking or tapping at cold start that fades as the engine warms, and ask whether the exhaust manifold or gaskets have been replaced.

   2 excerpts from owner complaints in NHTSA records

   “Ticking noise from engine has been diagnosed as a cracked exhaust manifold. This should be covered by GM as a warranty item since there have been so many exhaust manifold failures related to the 4.2 liter six cylinder engine.”

   NHTSA complaint #10263221, filed 2009-03, 70,000 miles

   “I own a 2004 Chevrolet Trailblazer Ext. Took the vehicle in october 2009 for a oil change & a exhaust leak was told the exhaust manifold needed to be replaced, after searching on the internet found out it is a known problem that GM when manufacturing the vehicle used bolts that were to long therefore the exhaust manifold wasn't properly torque/tightened which made the manifold vibrate until it broke and prior to its breaking it leaked the manifold becomes loose and that leads to it cracking. …”

   NHTSA complaint #10298357, filed 2010-01, 62,321 miles

Buying note. A 2004 Trailblazer EXT can be a workable used buy if the gauge cluster behaves and there is no fuel smell after filling. Budget for an instrument cluster repair and check the headlights and exhaust at night and from cold before committing.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.