my 07 at 57000 didnt do it. so far my 10 at 20000 dont.

 

Dig around with the search function a little more and I think you will find this topic has been discussed numerous times with no real answers found. I think the majority(of the few that have had the issue)of them got rid of the vehicle. I seem to remember someone successfully having the dealership go to great lengths replacing things trying to eliminate the noise to no avail.

I would suggest you use your years of experience working with other vehicles and apply it to this situtation. I don't mean a smart-*** "fix-it-yourself" kind of way but if you have been familiar with similar noises/issues before, look beyond the noise to the places where you've seen the effects. Look for evidence that the noise is causing a problem. I'm sure if you could take a cup of oil with metal shavings into the dealership with you they may be more apt to listen to what you have to say.

If you can't find anything operationally wrong with the vehicle, you either live with it or get rid of it. You've probably already screwed yourself at this dealership with service so you may want to find another place for service as well. From my own experience and from what others have related, I think dealerships want to distance themselves from Hummer owners as much as possible while your vehicle in under warranty. In their mind, they've already thrown you a bone with the tensioner pulley and thats the last of that issue. There are a few good dealerships out there as well. If you want them to tell you its a design flaw, they have no idea if it is or not. If you want them to acknowledge your problem and business is important to them, well I don't need to tell you.

Good luck

 

Well durrrrrrrrrtommy if I had the vehicle in front of me I am sure I could figure out where it is coming from. How quickly oil pressure builds on startup, lifter noise, timing chain, rod knock (hopefully not), accessories. Who knows, Kind of hard to figure out a noise from a keyboard.

I am pretty sure though that a 30 year master tech can figure out a noise complaint since he has probably had to do it several hundred times over his career.

 

the guy said he couldnt!! thats why hes here!!.i cant help either. i think wsh got it right

 

I posted a similar thread a year or 2 ago.I am a retired motor pool mechanic been spinning a wrench for a living since 1969.My new h3 started making that cold start up noise as soon as it hit 50,000 miles.While I am agenst opening up a perfectly good engine my best educated gess is a week oil pump.what I hear is lifters pumping up.I tryed a few oil changes using different weight oils but no change.The noise only lasts 2 or 3 seconds & only on a cold (engine not running for several hours)it could allso be a worn pump or leaking gasket between the pump & block allowing the oil to drain back down the system. that seal you see inside the oil filter stops the oil from above the filterfrom draining back down to the oil pan but after trying several filters I am thinking maybe the oil is draining back below the filter.Like I said i am not tearing down a good running engine I am sure the guys that work on these h3 all day long know what it is.I have 76,000 miles on my 07 & still love driving the vehicle.Its a keeper.When the noise continues for several or more seconds I will then tear into the engine.If anyone finds a easy fix please post it.( trading in the h3 is not the answer) Tom retired usn

 

Thanks to the ones that had something constructive to add. OK to the others, I get bored at times too.

The fact is that the engine noise seems to be on the 2007 H-3 only, perhaps not in all of them. The noise is coming from the front of the engine inside the timing cover.

The only time I ever had a similar case was on the Corvette ZR-1, 1989 double overhead cam engine which also uses a hydraulic timing chain tensioner as does the Hummer I-5 engine. On that case the engineers from the Stillwater OK Mercruiser factory which were in charge of building the engine came to the dealership where I worked and we did a complete tear down, measure and inspect.

After nothing was found wrong we decided to start the engine with the timing cover off and saw the timing chain bouncing back and forward and the camshaft gears doing the same causing a rattle knocking noise which is similar to what the H-3 has.

In the ZR-1 engine we replaced the hydraulic timing chain tensioner and the noise went away and never came back. On the case of my Hummer the Dealer under Tech Asst. also replaced the tensioner and it quieted the noise considerably for a few months but at around the 4th month started back louder than ever.

So we know the problem is there, I don’t want to do any work myself first because I don’t know what is causing the flutter of the chain and gears, I do know that as soon as oil pressure goes up the noise goes away possibly as the tensioner takes the slack from the chain.

This is a Hummer Factory GM responsibility and just wanted to know if anyone else was having the same problem or had a fix for it before I go further.

Thanks all.

 

Seems to me, there my be some panties in a wad about a whole lotta nothin.

The Atlas Series engine has hydraulically actuated timing chain tensioner that requires the oil pressure to first come up to add the required tension to the timing chain. Over time the chain will stretch, but the tensioner has ratches that will eventually allow it to click over to the next position to correct for the slack in the chain. Sort of like self adjusting brakes worked.

When you first start the cold engine, if the chain is loose and before the oil pressure can come up to take up the slack, the chain may contact the insides of the front cover. It sounds like a rattle that immediately goes away.

What is happening is the chain is loose enough to slap but not yet loose enough for the tensioner to click over to the next position. Not all will do this, but a bunch can for a while. If this persists for a long time, you may have a timing chain that stretched too far, or tensioners that are worn and need to be replaced.


GM TSB 06-06-01-017G covers the revised cylinder head and timing chain service procedures for these engines.


Many/most will tell you this is normal. I would say it is more expected than truly normal, but it is not a big deal IMHO. Life is good if this is all you are worried about.

My 07 hasn't done it.... yet.

 

i wonder if the engine control might be looking for the proper cam timing/hunting,briefly?
maybe "something"somewhere else is messing with it. maybe the position sensor itself?
and i am coming at this strictly form a position of knowing very,very little about it. a guess.

 

My 08 H3 does this as well.. I have the I5.. It is not enough to concern me. I will be concerned the moment that it lasts more than a few seconds... And I only have 46,000 on mine... Dont sweat it.. If it gets worse then take action.. Or if you got money to throw around, replace the Timing Chain...

 

after re-reading some posts on cam position sensor where i posted and forgot, i would be surprised if the position sensor was NOT involved.
even if it is ok itself , it can be affected by oil pressure or plugged up flow.
its a closely controlled system with electronics oil pressure actuators and the chain/chain guises,slides. a combo of possibilities.
now im not guessing