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Discussion Starter · #1 ·
Just replaced the fan clutch and waterpump but still have an "occasional" "roaring" sound depending on how the accelerator is being pressed. If you are light on the throttle then there does not seem to be a problem but if you hit it hard it starts to lock on up to 30-40 mph. I have read all the other fan clutch threads and that's what made me get the clutch. It seemed to work for a day or two but now it is intermitent rather than all the time. Could it be the sensor? Does anyone have the instructions for replacing the sensor? I read the Haynes manual and it is not to discriptive. Thanks for any help you can give.
 

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Which sensor? The one for fan speed is built into the fan clutch and isn't separately replaceable.

Is your coolant temp gauge showing a good solid 210 all the time?
 

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Discussion Starter · #3 ·
Yea temp is solid. The sensor I am talking about is the one from the engine that connects to the shroud, which connects to the fan.
 

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I'm pretty sure that's just the harness. The fan needs +12, ground, a command line to tell the clutch to engage or not, and a Hall Effect sensor feedback wire.
 

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Discussion Starter · #5 ·
Before I replaced the fan clutch and before the clutch went bad, I never heard it lock up unless we were stuck in traffic. Now it seems to come on more times then not at low speeds. Is this normal or could I hvae gotten a bad clutch from Napa? So you are saying there is NO sensor that controls the clutch?
 

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I don't think it's normal. As I said before, there IS a sensor, but it's built into the fan clutch itself. I have EFILive software that can examine the traffic on the OBDII data bus, and there are messages containing the commanded RPM and the actual RPM. If they disagree for long enough, the PCM will set a code and eventually turn on the Check Engine Light. A fan that locks on will have too high an RPM compared to the one it's commanded to run at, and one that fails to clutch properly will spin at too low an RPM.

As to what to do next - you have very little hard data to demand a replacement from NAPA, but you could try. A dealer's scan tool could confirm that your fan RPM doesn't always match what it's being told to do. In general, when your fan is spinning at a stable RPM, and you hit the throttle gently, it has time to react and unclutch so it doesn't overspeed as the engine RPM increases. With a fast throttle advance, they will always lag to some extent, before the clutch control takes effect. I seem to think this takes only 1-2 seconds. How long does yours roar under the conditions that bother you?
 

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Discussion Starter · #7 ·
It lasts up to 10-20 mph now. Not to awful long, but since I have owned it I have never noticed it unless I was sitting in traffic. I guess that is the anal part of me coming out. And the wife is the daily driver and she is on me about it now. "It has never done it before, can't you fix it" is all I hear now. Do I need to fix it correctley or get a new wife?:crackup::crackup:
 

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It lasts up to 10-20 mph now. Not to awful long, but since I have owned it I have never noticed it unless I was sitting in traffic. I guess that is the anal part of me coming out. And the wife is the daily driver and she is on me about it now. "It has never done it before, can't you fix it" is all I hear now. Do I need to fix it correctley or get a new wife?:crackup::crackup:
New wives can be very costly. The costly part is getting rid of the old one.
 

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It lasts up to 10-20 mph now. Not to awful long, but since I have owned it I have never noticed it unless I was sitting in traffic. I guess that is the anal part of me coming out. And the wife is the daily driver and she is on me about it now. "It has never done it before, can't you fix it" is all I hear now. Do I need to fix it correctley or get a new wife?:crackup::crackup:
tell her to turn up the radio :coffee
 

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Any update on this? I am having a similar problem. Just changed fan clutch, water pump and belt. Fan clutch ticking is gone, but still have loss of power. Engine temp is always at 205-210 give or take. I have a loud engine roar and loss of power. Engine roar is loud and usually at 3000 rpm and about 30-40 mph when acceleratingmoderatly. Does not really happen at slow acceleration but still has loss of power. Any ideas, questions or help is appreciated.
 

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Click on UserCP at the top of the page and fill in the blanks. That tells us what you have.
Welcome to the forum.
 

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So Roadie, I haven't changed mine, so this is just curiosity...Should the battery be disconnected when changing out the clutch to reset anything in the computer that it may become used to, like kicking on and off at certain times or do you think its just a difference in the magnetic strength in the sensor that is may be different from other manufacturers?
 

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You should disconnect the battery for safety, or pull the fan clutch relay so the harness has no power, but there is nothing that needs relearning with a new fan clutch. The sensor is just a sensor. If its output signal meets the threshold spec for the PCM to receive it, and they all do, then all the PCM is measuring is RPM, and that's a very easy parameter to get right. An analog sensor like coolant temperature might be more difficult.

For crazybos: To confirm it's the fan clutch, just pull the fan relay #45 under the hood and see if it still does it. The fan only steals 5 HP or so even when it's locked on, so that's usually not as noticeable as a partially-clogged cat, for instance. How many miles do you have and are there any other issues in the vehicle's history that could clog the cat, like misfires?
 

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Just replaced the fan clutch and waterpump but still have an "occasional" "roaring" sound depending on how the accelerator is being pressed. If you are light on the throttle then there does not seem to be a problem but if you hit it hard it starts to lock on up to 30-40 mph. I have read all the other fan clutch threads and that's what made me get the clutch. It seemed to work for a day or two but now it is intermitent rather than all the time. Could it be the sensor? Does anyone have the instructions for replacing the sensor? I read the Haynes manual and it is not to discriptive. Thanks for any help you can give.
Any update on this? I am having a similar problem. Just changed fan clutch, water pump and belt. Fan clutch ticking is gone, but still have loss of power. Engine temp is always at 205-210 give or take. I have a loud engine roar and loss of power. Engine roar is loud and usually at 3000 rpm and about 30-40 mph when acceleratingmoderatly. Does not really happen at slow acceleration but still has loss of power. Any ideas, questions or help is appreciated.
Hey guys,
i had this before you, took mine to the dealer over 10 times, came back the same every time :duh: ALL dealers techs and maintenance managers insists on its normality :rolleyes: so i finally gave up, i just think new FC are like that, our old ones or OE ones were something else, may be the old design was better for our OLD trucks :undecided just dont bother more if its like what Roadie says, the temp is fine and not moving then just accept it :yes:
 

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This problem has been ongoing for several months. I thought it was the Fan Clutch and properly research Trailvoy (Many Thanks) to make sure I was correct in it being the Fan Clutch. I bought the Dorman fromn Rock Auto. I replaced the Fan Clutch, Water pump and belt since I was in there. I did the Rev test and it sounds perfectly fine, no roaring or anything.

I just went out for another test drive and pulled relay 45 as per the Master. I definately noticed a power incrrease and the roaring is less but still there and still loud. I cleaned the Throttle Body earlier today after reading it on another post.

It is definately a ROAR or Howell sound when pressing fairly good on the gas. There is also a vibration now and the shifting seems off. I was driving easier prior to the fan replacement so I can not confirm that this was or was not happening prior to fan clutch replacement. I do know that was not always this way and was fine a few months ago. Thanks again for your help.
 
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