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2006 chevy trailblazer_ls
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Discussion Starter · #1 ·
I've got a 2006 TB (4.2, V6, 4WD) with 218200 on it. She's old. Recently got a rebuild transmission installed, and just did the starter myself yesterday. Now, the next project...

On a recent move from CO to CA I noticed two things. First the code (P0495) was thrown as I was climbing up I-70 out of Denver. This has happened before with and without a load in the car or on the hitch. No audible difference in the fan, no "jet engine" as many others describe, no overheating or appreciable temp difference. Each time it's happened I've reset the code and it doesn't trip again until a steep climb or with a trailer.

Towards the end of that drive I noticed a rattle noise coming from under the hood at low speeds/RPM. When driving at highway speed it seems to stop. Now the rattle is persistent on startup and at slow speeds.

Are these two things related? I've read a lot about fan clutches and water pumps. Trying to do the work myself if possible. Advice appreciated!
 

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2007 chevy trailblazer_ls
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With engine off...grab the fan and wiggle to see if any movement. Might be cause of rattle. There shouldn't be much play..if so..probably time for new pump. Good idea to swap out clutch too.
 

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2006 chevy trailblazer_ls
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Discussion Starter · #3 ·
With engine off...grab the fan and wiggle to see if any movement. Might be cause of rattle. There shouldn't be much play..if so..probably time for new pump. Good idea to swap out clutch too.
Thanks caliblazer! Message went to spam folder, not seeing till now.

Problem still persists.

There’s a little play there, but not too much. How much is within tolerance?
 

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2007 chevy trailblazer_ls
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There really shouldn't be any play. I just checked mine the other day...because I just went through and replaced pump/clutch, and tight as a drum.
Make sure fan shroud is tight and mounted correctly too. The fan actually spins inside a groove that's molded into shroud. Mine was cracked and was rubbing on fan occasionally. Didn't help that my fan was tweaked too...
 
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