Rattle coming from the front of the motor

[UNOMYFLO]

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

[hummerdonthurtem]

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.

[UNOMYFLO]

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

[hummerdonthurtem]

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.

[f5fstop]

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...

[UNOMYFLO]

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

[UNOMYFLO]

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

[f5fstop]

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.

[hummerdonthurtem]

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.

[hummerdonthurtem]

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.

[UNOMYFLO]

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

[hummerdonthurtem]

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

[Susan]

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

[UNOMYFLO]

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

[StarsnBars]

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.

[psywzrd]

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.

[StarsnBars]

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.

[UNOMYFLO]

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?

[ChevyHighPerformance]

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.

[StarsnBars]

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