It really did sound like a metal on metal kind of rattle. Honestly, I thought the horn bracket theory a while ago was much more plausible than a belt noise. I will definitely post back and let you know if it solved the issue. Mine started doing it at 30 miles on the odometer and it did get progressively longer in duration, which is what prompted me to actually take it over to the dealership.

New belt seems to have fixed it. Three cold starts with no noise. EVERY cold start had the rattle prior to belt replacement. Now, how does a belt cause a rattle noise...no clue...but it definitely sounded like a rattle (metal on metal).

Something that happened to me a few years ago on my heep. My h2o pump bearings were going, causing a rattle. I was on the road at the time and just had the ability to tighten the belt - did that, sound went away, but 2 days later the bearings went. Tightening the belt made the sound go away, but not the problem. Maybe it's not the belt getting changed, but the belt being tightened down more by the dealer?

Susan great to know I have heard a belt make some strange noises in the past but never the metal to meatl rattle noise. I will get the belt replacerd annd llet you know.

But as you say it did it EVERY TIME and now its gone proof enough for me.

Thanks for taking the plunge on this one for all of us. Seems like GM used some crap belts since so many of us are experiencing this problem.
I might even go to NAPPA and get my own and replace it myself.

Thanks for the help and please let us know if the rattle rears its ugly head again.

Mike

Hey Susan can you tell me exactly what they did on the repair ticket?
did they clean the pullys and replace the belt?

Or was it just a belt replacement.

Thnx
Mike

They cleaned the pulleys and replaced the belt. The tech said there was some 'contaminant' on the belt.

When I dropped it off they mentioned that some of the belt tensioners were not torqued correctly and that sometimes causes a noise. There is nothing about retorquing (sp?) on my ticket, but would they likely check that when changing the belt? That might be worth checking also.

I would chek the oil level , It maybe be low and when it warms up the engine is lube, when is cold the oil is down , the oil has to work its way to all the components that might make noise...Check oil..

Jose

Oil level is fine, its the serp belt.

Getting it replaced and the pullys cleaned and the tourque checked on the tensioner also.

U

My dealer is not accepting this solution...he does not beleive it is the belt...and since i cannot leave it overnight....I am stuck..anyone else got the same positive result by changing the belt...?

Thanks

Tell them to change the belt, there is a TSB on this issue. There were contaniments antifreeze that got on a ton of these and I too thought the noise could never be the belt and it was it could have been the tensioner bolt but the tech said it was fine he checked the torque. DEmand it or call GM and tell the dealer you will...they will change it. Leaving the trucvk overnight is crazy for a belt change. Shoot when I was down there I heard the new off the truck H3's doinmg the same damn thing on the way around the back to be prepped. Have them start a few that are cold on the lopt or better yet demand the belt change.


I thought I put the TYSB in my prev post for the TSb F5 can you help here?

Thats total BS for a 40 dollar belt.

WTF?

UPDATE:

It has been pretty warm here this winter SE GEORGIA.

This am it was 32 coldest it has been in weeks and since the belt change....the rattle is back...I do not feel the belt change and pully cleaning helped although they did say there were contaniments found on the belt and the pullys.

The rattle was also louder than ever, and it did the same ol.....once the truck was warm (and it took much longer even after the needle reached temp.) I also noticed the rattle changes loudness based on the throttle position...basically when I backed out of the driveway it got louder and changed the level of rattle as I applied the gas. Once down the street a bit it was gone.

I was standing on the pass side of the truck this am and now I have a hunch it might be a heat/exhaust shield under the truck. The reason I felt it was coming from the front of the motor (and it still might be this is all speculation at this point) is because I have always stood there and the way the under body cavity and contour is shaped (as in all vehicles) I think it is eminating from under the truck and the sound is traveling from under the body under the cavity for the transmission and out the underneath of the firewall into the engine bay like a megaphone.

I need to crawl under it this weekend as it is suppose to be cold. Every morning I have my dress chlothes on for work and it hasnt been an option.

Definately still there, definately cold and heat affected, goes away when truck is warmed up fully, which this am took much longer than normal.

I do not think it is internal in the motor. I need to get under the truck and check all the skids and all heat shields this weekend...

So bad news guys and gals I thought this was gone and to be honest it has been since the service 2 weeks ago, but again it got real cold here last night..

So I am still on the hunt for the location of the rattle and to stop it..

F5 Help! : > ) can you do some research on your GM computer to see if other techs have diagnosed the problem and fixed it?

The belt change did not fix it.
Thanks
UNO

I was reading in the manual and under index engine .... i cant remember what page. but it actually said in there that you might hear a rattle noise from a cold start for a few minutes until it warms up and it will go away. So this could be the noise. I know everybody is pretty good here about helping and fixing things. But maybe the answer was in the manual the whole time and just overlookes.
I will get my manual out and find the exact page.

Hi,

I still beleive it has to do with the fan/fan clutch and disingaging due to temperature (ambient and motor temp.)....does anyone have a manual that shows the cross section of how the fan clutch works ?

If the rattle is other than the clutch, it would not be temperature related....my opinion

After the belt change and the pullys being cleaned at the dealer a few weeks ago I still have it. I too believe it is the clutch fan mech. It is temp related and rpm related. Now when I fire her up and it has been colder here in GA when I back out of the driveway the rattle sound is closer together and gets louder 2 min into the commute to work it goes away. A good way to trouble shoot it would be to remove the assy and fire the truck up for a few minutes overheating wouldnt be a problem if ran for 2 min or so. I wonder if the clutch fans are defective...since this is not normal. I wonder how much the assy is I would like to get a price from advance auto if it is cheap I might replacre it to avoid the 4 hr round trip to the dealer..they might re-emburse me as I have a real good repor with the hummer manager...shoot I got a bruish guard fro free due to all the troubles I have had.

If I had time I would yank the clutch fan mech. I wonder if the fan shroud has to come off...probably so but it might be possible to remove the mounting bolts and work the fan and housing out...

The removel of the clutch fan is easy..just need the time.

I am going to call advance now and se if they have an app for a colorado or perghaps the H3 juts for my information....then I will call the dealer and tell them the rattle is not gone.

The encoder has resolved the stab light 4wd deal and the washer pump is replaced and working...if I can get this rattle to go away I am set.

Still love this truck..

UNO

UNO,

Mine is back too...I can hear it backing out of the driveway. Please post what you find out about the fan theory.

I am going to do my best to just ignore it for now!

Susan

I hear ya Susan bummer right?

I do notice that since it has gotten real cold her 20's it is worse and 3 weeks ago it was in the 70's and not really there. I wonder if when the summer comes it will be gone but I hope to have it resloved by then.

I used my digital camera's video function to capture some audio of the rattle so I can post it here to see if we all have the same noise.

It is an mpeg now and I have to figure out on my mac how to extract the sound and save it as an mp3 in a size I can upload. I know if it was on a web page I could link it to a url but I do not have one, so I am going to try and isolate the audio portion only and upload it on this thread. I am also going to hopefully find the time to remove the clutch fan assy ne evening then fire up the H3 cold and see if the sound is gone. I will only let it run for a minute or so to make sure it does not overheat, this is the only way to truly rule out or in the clutch fan mech as the problem or not....I really feel that it is.
Hopefull I can get that audio uploaded in the next few days but things for me now are crazy.
20mo old and 5 mo old at home I work 9hr days then come home to relieve my wife she goes to sleep and works 11pm to 7am.

Take care Mike

Has anyone been able to get this fixed yet?

f5fstop...any ideas ?

Any TSB's about this ?

Thanks

I had the belt changed and the tensioner checked and the pullys cleaned and I still have the rattle.

I still think it is the water pump but have not confirmed this.

They want the truck overnight and hopefully it will be a clod morning when they check it as it does not do it when the outside temp is over 50 degrees.

I also noticed when looking and listening with the hood opened yesterday I have some oil weeping from the timing cover bolt...the one that you can see right above the crank pully bad thing is to either remove it to put some silicone on it and re-install it to stop the SMALL leak or even to tighten it is impossible without removing the pully from the crank as just half of the head is exposed......

I figure when the bulliten is sent for the 1pillar plastic pieces and the roof rails which I hear they are going to swap out all 4 I will take it in and leave it and get a loaner..have the rails replaced and hopefully they will not crack again once they are re-designed...I will have them hopefully hear the cold start rattle and have them pull the crank pully and put some silicone on the timing cover bolt to stop the oil weep which again is slight but shouldnt be there with 3K on the odo.

DOes anyone have the rattle other than a cold firt in the am start up or does anyone have it in a warm climate like sandiego?

In GA it can be 70 one morning and it wont do it then 2 days later it is 37 and it does it..again once warmed up it goes away totally but until warm the rattle will get louder if the rpm increases while backing out of the driveway 3min later gone...tired of it. I checked all shileds and almost everything I could think of and I am still drawn to the clutch fan mech.

I would love to hear from someone who has had it fixed...I would like to put it to rest once and for all.

UNO

Bruce I looked in the manual as you said about the rattle and found nothing ..got a page number?

I would love to read it.

I still think it is totally not normal to have it though.shouldnt be there..

I have no rattle here in MI, and it has been colder than a "you know what." Finally took it to the dealer and got a new PS pump pulley to stop the squeak, and that has not returned.
You have a good idea about pulling the clutch fan and running the engine on a cold morning to see if this fixes the problem. Engine would not be hurt. I would suggest the dealer do this.
I'm at a loss guys. I have listened to at least six H3 starting up on very cold mornings, and not one had a rattle, only two had the belt squeak.

How about if we try getting this data. I have the metallic rattle and I noticed that when I start the engine the fan is engaged for about a minute (even after the H3 sets all night in 20 F weather). You can hear the fan noise when you rev the engine slightly.

Can you say if: 1) you have the noise and 2) you hear the fan noise when starting a cold engine.

If I remember correctly F5 said the fan mech is not electronic rather it has a heat sensitive bushing in it which when it reaches a certain temp the bushing expands and engages the fan itself causing it to rotate.

The fan mech and snout not the fan should always spin but again when the bushing heats the play goes away the bushing expands and the fan turns with the fan shaft.

Why then do our fans run instantly when the H3 is cold?

Th electronic fan mechs turn on when the sensor reaches temp and tells the computer to turn the fan on...if ours is not like this why does it spin when its 20 outside?


And not to beat a dead horse mine does not do it (the metal rattle sound) when the temps are higher...it was 78 today here in GA and it did not do it last week when it was 32 it was a loud rattle

Makes no sense to me really..

hey guys,
alot of posts here, and i'm a bit confused. i too have the same rattle on cold mornings and it goes away in a few minutes.
Whats the best course of action here? Heard a few possible problems regarding the noise. Should we take the truck back to dealer, let them keep overnight to try and locate and fix this?
Thanks

Yes plese take it in...due to scheduling I have been unable to do this.

My feeling is it is either the clytch fan mech or the belt tensioner.

This am it was 68 and I had the rattle, used to be it only did it when cold....now I am not convinced of that.

I did this am pop the hood and noticed the belt tensioner moving quite a bit and after the rattle went away I did her some noise from the tensioner perhaps it is the culprit? just cant be sure.

If you could take it in and leave it you would be helping a lot of people here on this thread.

The serpentine belt swap and the pullys being cleaned is not the fix so please tell them this.

It is in the front of the motor and I am almost 99% sure it is not a sheild of some kind
ie: exhaust shield or plastic motor cover.

thanks Boulder keep us updated.

UNO

OK the page in the manual is 5-33 it talks about the engine fan noise and says at the end ..

You may hear this fan noise when you start the engine. It will go away as the fan clutch disengages.
Is this the thing everyone is wondering about
Bruce

No the mnual is describing the ffan air movement noise the noise we have is a metal to metal rattle...definately not normal

but some people are complaining about a squeling like mine. i dont have a metal to metal rattle. i have a squelling. is mine normal then?
thanks

Its so damn cold here in PA,,i may not have to leave the truck overnight,,maybe just hang out for a bit.I'll report back, but it won't be soon, moving the family next week, so i have all that **** to deal with.
we'll get to the bottom of it..
thanks for the info unomyflo, narrowing it down is half the problem

there are 2 different noises. one is the squealing which IMO is a belt change or the tensioner needs to be replaced F5 posted a tsb on this and I believe he had his tensioner replaced.

the metal to metal rattle is different although it also comes from the front of the motor.

we are thinking clutch fan mech or tensioner is bad.

I personally had the belt replaced and the tensioner checked and they said it was fine.

I still have the rattle.

hope this helps..

I think the noise you have is the easier fix and yes I would take it down...I believe earlier in this thd the tsb for the squeal is listed bring it to the dealer...but they should know about it.....they wiull replace the belt and clean the pullys thee was some coolant contaminant on the pullys from the factory aparently which has cused the belts to squeal

UNO

no problem boulder if the dealer wasnt 2 hrs from me I would have had a diagnosis long ago..I am tired of hearing it to be honest.

super busy here also my 8 year old chocolate lab has cancer and I have a 20mo old boy and a 4mo old girl at home and my wife works 11p-7a thurs friday and sat.....I have my hands full... the noise has taken last priority ya know?

thanks boulder good luck on the move (moving sucks in general) cant imagine doing it with kids, almost have to get the new place set up totally then bring them in right? depending on the age of the child.

where are you moving from and where to? still in CO? how cold is it there? dude it was 32 here 4 days ago and yesterday it was over 80 the temp change here in SE GA is brutal....not complaining on the warmth but damn 48 deg difference? never did that in CT where I grew up and lived till 30 years old...been in GA for 8 still not used to it.....

take care keep me/us posted you do have the metal/to metal sounding rattle right? not the squeal?

I think we have 2 different nboises here proably should have a separate thd for each rattle thd and the squeal thd.


I have the metal rattle hopefully we get a fix for this soon.....

thnx UNO

thanks unomyflo, your right moving sucks,,,suburbs of philly pa here, 30 minutes north of the city, not moving far from there..
good luck with your situation too...

any word on this from the dealer anyone?

"the rattle"

I still havent made it into the dealer yet.

thanks
UNO

has anyone put a gates belt on instead of a gm ? i heard thats a fix and also a small amount of silicone lubricant on edges of power steering pulley . i had mine fixed was good for about 5k miles and came back .

No solution comment here . . . just want to commend everyone for their camaraderie. This forum is awesome. I'm still 5 weeks from delivery of my truck and feel the groove as though the problems were my own. Nice to know the caliber of good people here.