Does anyone else have a rattle noise coming from the front of the motor when starting their H3 in the am? It only happens when the truck is dead cold. I tried to pinpoint it this am and it sounds like it is either the clutch fan mechanism or perhaps the belt tensioner....really sounds like a heat shield but I pushed down on them and it didnt effect the rattle at all so I have to rule it out. Once the truck runs for a minute or 2 it goes away and will not do it again until the am (truck is comletely cold). I would love to know if anyone else is experiencing this or has has it diagonised or perhaps fixed.

It is definatelly coming from the front of the motor...

Thank You

Mike

I had a similar issue. I tighted the bolts holding what looks like to be some kind of sensor that is just left of center when you look through the front grill.

hmmmmmm thats interesting did your rattle go away a few minutes after warm up or did it do it all the time?
I will look in there in the am and tighten it up if it needs it.

did it stop your rattle? if this is it I wonder why it doent do it all the time can that parts mounting be affected by the temp of the motor?

Thnx

MM

The rattle I had was exactly as you described where it went away after the engine warmed up (could be due to less engine vibration from lower RPMs when warm). After I tightened the bolts, the rattle went away. Also I believe the bolt was metric and I had to use an extension to reach it.

Another place to look is the heat shield that covers the exhaust manifold. What happens is as it warms, it expands and stops the rattle.
Just another idea...

hummerdonthurtem

I checked it out this am and the only thing I see in there behind the grille just left of center is the horn?

Am I missing something bro?

Can you shoot me a pic of what wxactly was making the rattle and what you tightened up?
Its driving me crazy would be nice to stop it.

F5Fstop I hear ya but no shield on the face/front of the motor the noise is definately coming from the front. I'll be honest with you it really souinds like its the clutch fan mechanism.....

hummerdonthurtem send me some pics of what exactly you are talking about....much appreciated man.

Mike

I also used a long extension and pressed it against the heat shield and it diodnt change nor stop the noise.

I thought it might be noisy lifters until the oil reaches the rockers and heads totally but, its not the typical rocker ticking it a definate rattle like a chain dragging across a coke can....wtf?

F5Fstop as you know also these noises can radiate from nowhere and sound like they are right next to you.

Hopefully the pics or a better description form hummerdonthurtem will help me either fix it or rule that out like I said all I se in there is the horn assy. hummerdonthurtem you are talking about looking through the bars in the grille right?
in front of thee radiator? I got nothin but horn there..

M

Not sure what hummerdonthrutem is taking about, is the "sensor" on the engine or in the front grill area?
Could be the lash adjusters, no actual hydraulic lifters used. Whatever it is, it definitely sounds like once it gets warm, it expands and stops the rattle.

Here is a picture, looking straight at the front grill. The two arrows show the locations (approximate) of the bolts. Note that the upper bolt is a little behind the grill.

I didn't know what the round black thing was in the picture above. There are two bolts holding this down, one on top and one below. Needed an extension to reach the bolts. Hope this helps.

Thanks man, yeah its the horn, so you say the 2 horn bolts were loose?

I will check it in the am

Thanks for taking the time to take the pic for me I really appreciate it I hope this is it.

I will let you know

Mike

That's the horn? Wow, no wonder it sounds to wimpy....LOL

UNOMYFLO,

Did you try the fix? I just picked my H3 up last night and I heard the same noise this morning.

If it is that simple to fix, I will just do it myself.

Thanks

The poteential fix was to tighten the horn mounting bracket (1 bolt) inside the grille to the left. Mine is tight and is not the problem.

It sounds to me like it is the clutch fan mechanism although there is no play in it.

Not sure what to do here the rattle is substantial when cold and upon initial start up in the am. after 1 min it goes compltetly away and wont do it again until the next am..

I am baffled??

anyone else had theres in for this or know what it could be? definately from the front of the motor for sure sounds external and not a heat shield.

M

I get the same noise too. Im going to call my dealer and see if he has any info. Will post back if I find anything out.

I have this noise too - drives me f***in' nuts! I was going to have them check it out when I go for my first oil change and have the recall work done.

I called my dealer and he said that was the first he had heard of that issue. He checked GM's site and came up empty. I guess someone will get it figured out and hopefully post the fix.

Thanks everyone for the back up my dealer is an hour and a half from me and even driving down there isnt an option as it wont make the noise then. I would have to leave the H3 thee overnight and get a hotel and stop in in the am and have the tech start it cold and he will have like 50seconds to diagnosis it.

Strange it can be so loud and F**in annoying and then 1-2 minutes later be completely gone. It is definately something that resolves itself once the motor is warm and for me wont do it at all again that day even after sitting in the lot at work for 5+ hours before lunch but to be honest wioth you it must take a good 10hrs for the motor to completely cool down to the outside temp.

For those in colder climates it must make the noise much longer until the H3 reaches temp.


Please anyone keep me posted.

Oh I got my rear washer pump recall in the mail today also it will go in for that when the noise is fixed.

I still say it sounds like the clutch fan, but cant confim this to be true.

I juts got the new onstar module replaced 2 weeks ago after major sh*t with onstar they ewanted me to keepo having it trouble shot aftter 4 attempts top fix I demanded a new module sad thing is the tech new it was that all along. Nice to have it working though and now the noise. No biggie I LOVE this truck it rocks period hands down.

Please post what anyone finds, not sure how any tech will hear it as it is only on cold start up.


Come to think of it when I was doen in Jax at the dealer for the onstar repair they were pulling new H3's around to be prepped for sale. I actualy herd the rattle from one of them but the tech was on the road with my H3 to road test it . When he came back I said this H3 is doing it (rattle).

He actuall went to get the key an fired it up and guess what the roide from across the parking lot must have been enough to warm the truck and it didnt do it.

I truly feel the only way any of us are gpoing to get thsi diagnosed correctly is if someone is willing to park it in the dealer lot overnight and meet the tech by the truck and have them fire it up. Mine is loud they would definatelly hear it for sure.

Keep me posted and thanks to all glad to see I am not alone on this one.....

Is everyone who posted here experiencing the exact same symptoms?

I hear the same noise only for the first minute or so. It seems that the PCM is programmed to engaged the fan even though the engine is cold perhaps to place a laod on the engine to help it heat up and get into closed loop.

Makes sense CHP. The little noise on mine lasts about 20 seconds or so and it has to be stone cold to do it. I think if there was something loose it wouldnt go away. Ive only noticed it a couple times about a week ago when we had 0 degree weather and it sat outside work for 10 hours. I ran bolts and nuts in the engine area and came up empty. so Im going to just enjoy the ride for now... Happy Holidays

Hi we got our H3 in Germany and had the same noise after 100 miles,the dealer will change the belt next week i dant belive this will sove the problem
keep me informed
Frank

Hi,

I have the same rattle noise...also when cold (which is always as I live in cold Canada)
It also goes away when the engine warms up...keep me posted if you find the solution....thanks

My H3 is 6 mos old and when it was new it made a squeeling noise when cold. It was the serpentine belt. Once they changed it the noise went away.

Cooling fan is totally mechanical, PCM has no control. It is controlled by a mechanical fan clutch.
Maybe it is the clutch? Evidently, something is heating up, and expanding.

Its not a squeeling noise it is a RATTLE/ VIBRATION noise. I have been restoring cars and working on them for 20 years and I have never heard a serp belt make a rattle noise. I am with F5Fstop I think it is the clutch fan mechanism...when the heat sensative bushing inside of the mounting area heats it expands and engages it, plus it must tighten up the juncture and eliminates the noise...I would like to have a definite on this though. I could pull the fan mech and check it just for the short start up period to see if it eliminates it.

This is so wide spread I wonder if HUMMER knows about this problem....?

I have a rattle, but it's not when the H3 is cold to warmup--it's when speeding up or pressing the break to stop. I went and checked all areas mentioned in this thread and everything is tight. I did notice that my fan shroud isn't tight and I can shake it, but I can't determine how to tighten it.

I have actually listened for this rattle on cold mornings and have not heard a rattle. This damn H3 seems to be flawless, and was until last week, when the rear passenger door outside handle stopped working.
Pulled off the trim panel and the handle's latch rod fell off, repositioned it, popped it back into place, and all is well.
I can hear a slight squealing on a cold engine start, but pretty sure this is the tensioner or idler pulley and eventually will take it into the dealer for repair.

Today the dealer changed the belt ,and the noise is gone,no noise at all

have a great 2006
from Germany
Frank

Where in Germany are you at, Reason 'm askin' is I'd like to know how your experience was with the dealer.

Thanks

Frank did you have the 50second rattle? or was the noise a squeaking sound?

This am it was warmer then it has been and no noise first time in 3 months...very odd.

I stand by the truck every am and wait for it and this morning nothing....

Shoot if it is the belt I will go to Advance Auto or Autozone or Nappa and buy a belt and put it on myself....the dealer is 2 hours from me.....worth the cash out of my pocket to stop it...I doubt they would send me one.

I would like them to send me the updated rear washer pump so I could put it in myself also.

It would take me longer to get to the dealer than to have the pump installed.


****Not to beat a dead horse but did the belt swap stop the rattling noise? If this is the fix we all are going to get off easy for sure. My biggest fear was a timing chain or something internal inside of the front of the motor.

Let me know
Thanks Frank

Mike

I know some early vehicles had some idler pulley problems, but it was more like a squeak. I guess it might cause a rattle too on some applications.
In my opinion a belt would squeal or squeak, but not rattle.

f5fstop,

Is our fan clutch purely thermal or does the PCM control the clutch?

PCM has no control over the clutch fan, purely mechanical, controlled by temp of the air flow through the radiator, as it affects the clutch.
There are aftermarket electric fans available, but I did some research a few months back for H3Lady (I wonder what happened to her ), and the weight savings was not that great, since the fan and clutch are pretty light.

We live in Aachen and our dealer is in Düsseldorf

have a great 2006
from Germany
Frank[/quote]
Where in Germany are you at, Reason 'm askin' is I'd like to know how your experience was with the dealer.

Thanks[/quote]

'm in Bitburg, there's a dealership right outside where I live but it seems like they're a 'lil difficult to deal with. I tried to ask them to order a roof bar set for me and they said it's better If I oredr it from the states 'coz it's going to be expensive and it's going to take a while though them. I mean Damn..'m paying for it. Anyway, I think it's because I didn't get my truck through them. BTW if u don't mind me askin' how much did you pay for yours, they're selling theirs at 55,000 Euro.
Where in Germany are you at, Reason 'm askin' is I'd like to know how your experience was with the dealer.

Thanks[/quote][/quote]

Hi,

I beleive it is the fan clutch too...as when the engine is warm, or at least started earlier in the day, the noise does not come up. also,as soon as you turn your engine, the fan is usually engaged for a few seconds and the noise is not heard.

Im having the same problem.
any new ideas or fixes for this?

I just picked mine up from service for this issue (at least it sounded the same as the descriptions here). They changed the serpentine (sp?) belt and cleaned the pullies. Hopefully, that will fix it. I will not know until the next time I start it cold.

There is a TSB for the Colorado for coolant getting on the belt and causing some noise. I found it on a Colorado site...same engine; possibly same noise/cause? We will see.

You say you had the RATTLE right? not a squeel/squeak or any other type of noise?

If you had the RATTLING noise and they changed the belt and it works please let us all know ASAP.

Hard to believe a belt swap would stop a rattling noise but I hope it does.

Thanks so much

Mike