By January 30, 20065 Comments Read More →

Chevy Trailblazer Check Engine Light On After Fuel Tank Replaced

Hello Austin,

I have a question for you that involves figuring out if our
dealer is charging us for a repair that is needed due to their errors while fixing the original diagnostic problem. We first took our vehicle in because the engine light came on.

The Chevrolet dealership told us we had a tiny seam that was coming apart on the gas tank. Supposedly they replaced the gas tank at $1000 cost and did some other regular maintenance (fuel filter replacement, MOC Engine Decarbon Flush service, engine decarb, checked air pressure in tires, MOC Fuel Injection flush service, )

The next day the light came on again and we took it back to the dealership, and they told us the gas cap was not on tight enough. A few days later the engine light came on again, and it took another three days or so for them to figure out that, they needed to replace the “fuel evaporation canister” that they “may have” damaged when replacing the fuel tank?

Here is the question finally – When we went to pick up the car it made a light roaring noise when pressing on the accelerator. We were told that this was the fan clutch, but it had nothing to do with any repairs or maintenance they had performed.

Is there anything they could have done while running the diagnostic tests, making the above repairs or maintenance that would have caused problems with the fan clutch? It just seems oddly coincidental after taking it in for one problem it drives out with a second problem that at first we were told the noise did not exist?? At this point we are even wondering if the fuel tank even needed to be replaced.

The fan clutch problem occurred right after they were running diagnostic tests again for the check engine light problem.

Thank you for any advice, or help you can provide.

2003 trailblazer, 56,289 miles


Thanks for your email. My gut says you might not have needed a new fuel tank. The check engine light was probably coming on because of a leak in the fuel system, not allowing it to pressurize itself. Not tightening the fuel cap all the way is a common cause for loss of evaporative fuel pressure. I hope the new fuel canister corrects the problem, and was probably the problem all along…just my guess anyway. I don’t want to place poor judgment on the dealership…ok ok , maybe just a little blame should be placed on them. 🙂 

Your new concern with the fan clutch is probably not related to the previous work, although anything is possible. They are admitting some guilt in damaging the evaporative canister (mechanics rarely admit ANY guilt) so I suppose they could have damaged the fan clutch as well, but probably not.

Some fan clutches are noisy if they are fully engaged and working as hard as they can. The fan clutch is attached to the fan blade behind the radiator, and its job is to spin the fan blade faster or slower to suck air across the radiator as the engine heats up.

When the engine is hot, the fan clutch engages the fan blade and spins the blade as fast as it can. This can cause the fan to make a roaring noise, and some “roaring” noise is normal when engaged. When the engine cools down the clutch disengages and the fan spins slower.

Running the a/c can cause the fan clutch to engage, thus making a roaring noise…or at least more noise than when not engaged. A faulty fan clutch can stay engaged all the time which makes the fan spin faster all the time, which can cause the roaring noise to be more noticeable than when the fan blade is cycling on and off. So, if this roaring noise is present all the time, you might have a bad fan clutch.

If the dealer is to blame or is this just coincidence, that will be hard to determine. If the roaring noise comes and goes, then this might be a normal noise and could have been there all along, and you are just more noticeable of the vehicle’s performance and characteristics (and noises)… which you should be with everything you have been through.

If you are convinced the noise is new (and present all the time) you might want to consider asking the dealer to provide the labor to install a new clutch for free, as long as you purchase the part from them. I do this at my shop when a customer has a problem they think is my fault, but they really can’t prove it and I really can’t disprove it. I will absorb the labor cost if they purchase the part from me.

One thing you should check – make sure there is enough coolant in the radiator itself, not just in the radiator overflow bottle, but inside the radiator. If the engine is overheating, the fan clutch will engage to spin the fan faster to help cool the engine down. I would rule out the probability of engine overheating first before replacing the fan clutch.

Keep me posted,
Austin C. Davis

Follow Up

Hello Austin,

Thank you very much for your e-mail. It really helped.

Well guess what – the engine light went on again yesterday!! We took it back in and spoke to the general manager –will keep ya posted.

Take care & many many thanks,

5 Comments on "Chevy Trailblazer Check Engine Light On After Fuel Tank Replaced"

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  1. Frank C. says:

    Experiencing similar fuel evap problem with 2004 Trail Blazer LT.
    Error P0442 displays recurrently. This is a fuel tank inlet check valve fracture. Check engine light comes on only after fuel level
    falls below where the inlet check valve connects to the fuel tank.
    GM issued a recall on the extended body models 2004-2006, but not
    yet on any other models. Dealer estimate to replace tank is $1200.
    Am waiting to hear back from GM next week.

  2. john says:

    Amanda there is a recall on Trailblazer gas tanks…….someone owes you money

  3. Dan says:

    Fan clutches are a common failure on trailblazers. I have a 2003 LTZ with 115K miles and have replaced it twice. Actually, the first time was right after another repair….just coincidental. I am now trying to find out if I can replace teh evaporator canister myself.

  4. Bob Jones says:

    I had the same problem, I had a new water pump put in and now I get the roaring noise from the fan. The dealer reprogramed my computer, but I still get the roaring noise.

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