# [SOLVED] 06 chevy 4.2L v6 mpi engine noise



## tom99S104x4 (Aug 10, 2009)

hi everyone. I have a question for you gm techs. I am thinking of buying a 2006 chevy trailblazer 4x4 with a 4.2L v6 mpi engine and 33k mls. when the engine is running and you rev it up you here a humming noise ,and when you let it iddle you can barley here it, if at all . when driving it you here the same thing when you stop and go. i have a 99 s-10 so this is the lattest model car i have ever driven. to me it sounds like on an older car when the power stering pump is low on fluid and it starts to make that kind of winning, humming noise . I was told that this noise was normal for this engine. can anyone tell me if this is true or is this dealer peeing on my leg and telling me its raing. Thanks Tom


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## 97'sonoma (Feb 15, 2010)

*Re: 06 chevy 4.2L v6 mpi engine noise*

ummm the dealer is an pos cause 4.2 is the new inline motor not a v6 only v6 in the 4 liter range is 4.3 as far as gm goes and 06 making any noise like a power steering pump is bad. the only time my newer chevys did that is when i drove the living pess out of em and then some. I would NOT by that trailblazer but they are good vehicles. GMs are a better choice. cheaper to fix and fix it less often.


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

yea i was going by the carfax read out that said it was a 4.2 v6, i checked further and saw another discription of it and it said 4.2 I6. the engine runs strong and is quit, the noise to me seams to be comming from out side of the engine , i think one of the parts the serpantine belt goes around like a pully ,ac compressor, altenator, power stearing. the dealer is a suzuki dealer and does not know much about gm cars. he had one of his machanics look at it and hes the one who said that this nosie is normal for this engine. I did not think so, thats why i asked for other opinions. Thanks for your response sonoma. i am going back to look at the truck on sunday so any other input would be great. thanks tom


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## SABL (Jul 4, 2008)

*Re: 06 chevy 4.2L v6 mpi engine noise*

My son is checking something that sounds like your problem.... the clutch for the cooling fan. Not cheap....


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

hi sable, i checked my local autozone and a fan clutch is $199.00. i can change it myself if i had to, but if i buy the truck they offerd me a 3 month 3000 mile warranty on it. i asked for more and they said they are willing to talk about it. they sell small cars at there delership and no one pays atention to the truck when they come looking at cars, so they just want to get it off there lot. the gm dealers in my area want $18,000 for this truck with 48k and up on them. they were asking $15,000 and i offerd $14,000 and they said yes. after i looked at it and drove it i told them about the noise it makes and would have to think about it. thats when they had there mechanic look at it. so they came down to $13,000 and the warranty and i told them i will see them on satrrday.


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## wolfen1086 (Oct 4, 2007)

*Re: 06 chevy 4.2L v6 mpi engine noise*

I've been around every engine from a electric scooter to a multi-million dollar aircraft and I'll tell ya right here and now there's something wrong with either that engine or one of the accessories, engines should run smooth and make no abnormal noises, you might want to take that thing one test drive over to a real mechanic. and don;t listen to car fax about the engine the Chevy 4.2 is an I6 not a V6. Car fax also isn't that reliable I know they said my Chevy S-10 Blazer was crushed in 1992, kinda funny since I drove it to work today.

don;t buy that truck unless somebody RELIABLE looks at it and ok's the engine and drive train, also test the 4WD system make sure it works, ya think a fan clutch is fun try the little vacuum switch on a transfer case, or trying to figure out which wire in the push button 4wd is not attached where.


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

ok here is what i did today , i went to a gm dealer today that had three gm certified 2006 trailblazers for sale with the same I.6 engine . i told the sales man I was looking to buy one and i started the three of them and they all sound just like the one I want to buy. they have a slight hum to them when you step on the gas peddle. i guess i am so use to my 99 S 10 v.6 with 110K on it being so quite i got nervous when i heard how that engine sounded. when i go back to the dealer tommorow my friend who is a mechcanic will go with me to do a final once over. Thanks for your reply wolfen. I am still open for any more thoughts. thanks tom


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## wolfen1086 (Oct 4, 2007)

*Re: 06 chevy 4.2L v6 mpi engine noise*

Your welcome, I have a 89 S10 Blazer and the noise out from under my hood is either the fan, which is steel, or the raw power the 4.3 non vorteck is pumping into the transmission. But if its nothing bad then it could be anything from a power steering pump to some smog device making that humm.


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## 97'sonoma (Feb 15, 2010)

*Re: 06 chevy 4.2L v6 mpi engine noise*

i do have some experience with ford i6 like the 300 inline and they have a tendency to hum when you gas them but that's because their cooling fans blades have a greater angle to them but in a truck that new you shouldn't be able to hear it from inside the truck.but if this thing red lines at 6g like most other newer vortecs then the blades should be at normal angle and if their not then it will burn up the fan clutch cause its trying too hard to turn it at higher rpm than it should. when your mech friend checks it out have him listen under the hood while you gas it ,and see if is louder when you're in gear. let us know what happens then.


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

hi everyone, my friend could not make it on sunday to look at the trailblazer, but said he would stop by the dealer today on his lunch break. he just called me and said the truck just needed a ldler pully and every thing else tested and looks ok. i called the dealer and he said there changing the pully now and i could come in around 5 today to check it out . i'll let you all know what happens. thanks tom


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## 97'sonoma (Feb 15, 2010)

*Re: 06 chevy 4.2L v6 mpi engine noise*

cool beans man,i shoulda thought of that let us know if that fixed it!


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

well i whent back and drove it with the new pully in it and the noise/hum i herd before from inside the cab and outside was gone. i bought the trailblazer and drove it home. it drives nice and smooth and climbs the hills with no problems. when i bought my 99 S10 i ordered the factory service/ shop manuals for it and paid $75.00 for the three book set. i want to get the manuals for this one to, and found out there $300.00 now. its still worth it if you think about what they charge you to fix somthing these days. thanks for all the input guys.


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## Nucleartractor (Jul 31, 2008)

*Re: 06 chevy 4.2L v6 mpi engine noise*

I would just like to add, a fan clutch should not cost over $100. I got one made in USA from a local auto place for a little over $50 (For a 1998 S-10 Blazer). Fan clutches are consumable, so if yours costs that much, do yourself a favor and switch to electric -- then think of all the extra space you'll have under the hood. If you're doing it yourself, make sure you wire in that it will come on with the A/C compressor regardless of engine temp.
The same is true for idler pulleys -- between 15-30 bucks for them and you get what you pay for. I put in a factory air idler pulley (el-cheapo) and it ticks exactly like a clock and probably won't last as long as a name brand one you'd get either from GM or from a place that rebuilds parts like napa.
Oh, and Wolfen, what's it like driving a crushed truck? LOL! You should put that on a bumper sticker! 
Have fun with your new vehicle and happy driving! Any questions you have, this is a great place to post them.

BTW:
Alright! We're really starting to get some S-10 people here.

Regards,

Thomas


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## 97'sonoma (Feb 15, 2010)

*Re: 06 chevy 4.2L v6 mpi engine noise*

these 4.2's are diff than your 4.3 they are inline 6 and i believe they turn opposite of other chevys. new engine new parts higher cost, supply and demand


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

I just just checked out autozone for an idea how much the fan clutch would cost. i have about 5 or 6 auto parts stores in my immidiate area and the prices and warranty for the same parts can vary alot. I just changed cv.axl., bj. bush. whl hub ber *** , rotors and pads on front and back on my 99 S10 p/up and bought the parts from three stores because the prices and warranty varied so much. I went back on the site that sells the service manuals today and the manual set for the trailblazer was 300.00 yesterday today its on sale for 135.00 so i orderd it, glad i did not order it yesterday.if anyone is interested the web site is helminc.com. i bought the 3 book set for my 99 S10 and they are the the shop manuals the dealers use, very good info inside. i am not a mechanic but if i have the right info i can remove and replace anything. i am also learning how to use some electronic test equiptment. i can say since i bought the books i have saved big bucks on auto repair bill, and the best part is my wife cant say anything when i see a new toy O i mean tool and i want to buy it LOL. thanks thomas, i definatly will enjoy the new truck seeings that my 1 year old German sheppard has to ride in the back cargo are now insted of sitting in the pass. seat of my S10 and giving me wet willies.LOL. he will be pissed off for a while but now we can take him to more places with us instead of leaving him home all day in his crate. i will keep the electric fan in mind if i have problems with the pully again. have a good day all


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## wolfen1086 (Oct 4, 2007)

*Re: 06 chevy 4.2L v6 mpi engine noise*



tom99S104x4 said:


> well i whent back and drove it with the new pully in it and the noise/hum i herd before from inside the cab and outside was gone. i bought the trailblazer and drove it home. it drives nice and smooth and climbs the hills with no problems. when i bought my 99 S10 i ordered the factory service/ shop manuals for it and paid $75.00 for the three book set. i want to get the manuals for this one to, and found out there $300.00 now. its still worth it if you think about what they charge you to fix somthing these days. thanks for all the input guys.


I would have thought of that if I'd ever seen one that hums when its bad, the ones I've seen in 30 years under hoods either squeal like a stuck pig, seize up and squeal like a pig, or snap the holding bolt from the bearing being so bad it wears out
A FSM is a good thing to have, and they are always the best bet for any one particular item on one certain model but I found out a long time ago that Haynes does a good job of making repair manuals that the normal person can use if they have a general idea of which end is up. Check into those too.


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

your right wolfen the haynes books are very good to, infact i had the haynes book first and bought the fsm for more technical info. for my S10. sometimes i have to look at the haynes book because the fsm gets to technical for me to understand what there talking about, and the haynes lays it out in more laymans terms. and haynes has more pictures LOL. I will pick up a haynes for the trailblazer to. maybe the pully was just starting to go bad and humed before the squealing started. anyways have a good eve.


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## wolfen1086 (Oct 4, 2007)

*Re: 06 chevy 4.2L v6 mpi engine noise*

Another thing I love about haynes over some other manuals ( not FSM's) is that Haynes assumes that you already know how to open the hood


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## tom99S104x4 (Aug 10, 2009)

*Re: 06 chevy 4.2L v6 mpi engine noise*

ok guys i guess its time to close this one , and thanks for all the input. i see some more interesting threads out there.


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