Dealer Repair Attempts Failed....?

4wd · May 20, 2011

Okay!

Why was it quiet the first few days after the last repair?

As for aluminum, why other competitor' aluminum engines don't knock in the morning?

Also, while in the shop in the morning we picked a Tahoe with same engine which was sitting overnight and started it , no noise what so ever?

Anyway, I got your point! and don't mind if it didn't get worse.

07YukonDenali · May 20, 2011

My '07 Denali has excessive piston slap. It's also burning oil. Dealer wouldn't do squat, and now the warranty expired.

Have a F-150 Platinum w/ the EcoBoost on order. Will never step a foot in that GM dealership again.

jro909 · May 20, 2011

My '07 Denali has excessive piston slap. It's also burning oil. Dealer wouldn't do squat, and now the warranty expired.

Have a F-150 Platinum w/ the EcoBoost on order. Will never step a foot in that GM dealership again.

awsome, i'm willing to bet you will spend some time at the dealership with that ecoboost(seeing its on its first gen) and two i've had piston slap for going on 5 years now and for the 15 seconds on rare occasions it happens i live with it

SouthCo · May 21, 2011

I put 5w30 synthetic and 10w30 and no change, always ACdelco filters and still have about 20+k before warranty expires, engine is 5.3 aluminum.

The valves short knock does not start immediately after engine start..Engine starts normal with normal RPM surge and sound is very smooth for about 15 seconds then after that the RPM drops, you can hear the engine quiets down, at the second RPM drops down to idle RPM there is the valves knocking for about 10+ seconds...This is the same noise when it was knew and listening to all those who believe it's normal and would not hurt anything I was planning to just ignore it!, but from experience it got worse with time and the noise propagated to the top of the engine and you could hear some kind of steel sharp noises like a whistle.

One technician mentioned something about pressure or change of pressure...

I believe the root cause is something else and still there, what we did was just replacing the parts that are impacted by the problem.

Regarding piston slap, does it starts immediately after engine starts? I mean the from the first second..

theres your problem an aluminum engine, aluminum expands and contracts alot, so the tolerances on a cold engine are greater than a warm engine. definitly wouldnt want an aluminum engine in my truck, my charger has one and it is noiseier than heck.

It's quite and then noisy all in less than 30 seconds. I doubt that is long enough for heat to build up and cause the aluminum block to be the cause. I think your reaching. Alot of manufactures use aluminum blocks/heads or both and have for some time.

07YukonDenali · May 21, 2011

My '07 Denali has excessive piston slap. It's also burning oil. Dealer wouldn't do squat, and now the warranty expired.

Have a F-150 Platinum w/ the EcoBoost on order. Will never step a foot in that GM dealership again.

awsome, i'm willing to bet you will spend some time at the dealership with that ecoboost(seeing its on its first gen) and two i've had piston slap for going on 5 years now and for the 15 seconds on rare occasions it happens i live with it

The noise depends on the weather. When it's cold out, it will do it for over a minute, but when it's warm, it's usually gone after 20-30 seconds.

I don't have a problem with the EcoBoost spending time at the dealer, as long as they fix it, and not put the repair off until my warranty expires, like this GM dealer did.

jro909 · May 21, 2011

My '07 Denali has excessive piston slap. It's also burning oil. Dealer wouldn't do squat, and now the warranty expired.

Have a F-150 Platinum w/ the EcoBoost on order. Will never step a foot in that GM dealership again.

awsome, i'm willing to bet you will spend some time at the dealership with that ecoboost(seeing its on its first gen) and two i've had piston slap for going on 5 years now and for the 15 seconds on rare occasions it happens i live with it

The noise depends on the weather. When it's cold out, it will do it for over a minute, but when it's warm, it's usually gone after 20-30 seconds.

I don't have a problem with the EcoBoost spending time at the dealer, as long as they fix it, and not put the repair off until my warranty expires, like this GM dealer did.

don't know if you know this but almost all v8s from all brands have some sort of cold noise..from the people i meet at work ford is being a stickler on fixing powertrain issues(not brand bashing thats my honest experience from guys coming into work with truck issues specially the new powerstrokes)

4wd · May 21, 2011

The noise is Valves Clattering, and I am not sure about how many seconds, I say seconds because it is not minutes..last time it got worse, first valves start to clatter then sharp noises start from the top of the engine with some kind of whistle...I think change of oil pressure is the cause, despite the replacement of oil pump for the second time...confusing

tricel1 · May 21, 2011

I had a 2008 Tundra that had cold start knocking for 3 years, until I got tired of listening to it.

So I traded it in a new Sierra.

Okay!

Why was it quiet the first few days after the last repair?

As for aluminum, why other competitor' aluminum engines don't knock in the morning?

Also, while in the shop in the morning we picked a Tahoe with same engine which was sitting overnight and started it , no noise what so ever?

Anyway, I got your point! and don't mind if it didn't get worse.

martinzel · May 21, 2011

I put 5w30 synthetic and 10w30 and no change, always ACdelco filters and still have about 20+k before warranty expires, engine is 5.3 aluminum. The valves short knock does not start immediately after engine start..Engine starts normal with normal RPM surge and sound is very smooth for about 15 seconds then after that the RPM drops, you can hear the engine quiets down, at the second RPM drops down to

idle RPM there is the valves knocking for about 10+ seconds...This is the same noise when it was knew and listening to all those who believe it's normal and would not hurt anything I was planning to just ignore it!, but from experience it got worse with time and the noise propagated to the top of the engine and you could hear some kind of steel sharp noises like a whistle. One technician mentioned something about pressure or change of pressure... I believe the root cause is something else and still there, what we did was just replacing the parts that are impacted by the problem. Regarding piston slap, does it starts immediately after engine starts? I mean the from the first second..

I have the exact same noise.Only after a 3hr. or more cold soak. Mine does not start until mine goes to curb idle. After about 15-20 sec. tapping noise starts and lasts for 15sec. To me it sounds like lifter or valve train noise,if i raise the idle when its tapping the noise goes away....I keep thinking lifters Im at 8000k now,it started at 2700 miles, I cant say its gotten worse ,stayed the same I went to the dealer and had them listen to it,truck was there 4hr before they started it , they heard it and told me piston skirts.To me i am not convinced thats the root cause of it At this point Im not sure if it is a piston rattle or liter issue If it is a piston rattle theres not much to do but live with it I'v tried to pull coils one at a time before starting it on 3 separate cold starts.No major difference I thought piston skirt noises,cold start knock were more like a rattle,loud knock??? Can anyone comment on that?? Thanks Chris

jro909 · May 22, 2011

I put 5w30 synthetic and 10w30 and no change, always ACdelco filters and still have about 20+k before warranty expires, engine is 5.3 aluminum. The valves short knock does not start immediately after engine start..Engine starts normal with normal RPM surge and sound is very smooth for about 15 seconds then after that the RPM drops, you can hear the engine quiets down, at the second RPM drops down to

idle RPM there is the valves knocking for about 10+ seconds...This is the same noise when it was knew and listening to all those who believe it's normal and would not hurt anything I was planning to just ignore it!, but from experience it got worse with time and the noise propagated to the top of the engine and you could hear some kind of steel sharp noises like a whistle. One technician mentioned something about pressure or change of pressure... I believe the root cause is something else and still there, what we did was just replacing the parts that are impacted by the problem. Regarding piston slap, does it starts immediately after engine starts? I mean the from the first second..

I have the exact same noise.Only after a 3hr. or more cold soak. Mine does not start until mine goes to curb idle. After about 15-20 sec. tapping noise starts and lasts for 15sec. To me it sounds like lifter or valve train noise,if i raise the idle when its tapping the noise goes away....I keep thinking lifters Im at 8000k now,it started at 2700 miles, I cant say its gotten worse ,stayed the same I went to the dealer and had them listen to it,truck was there 4hr before they started it , they heard it and told me piston skirts.To me i am not convinced thats the root cause of it At this point Im not sure if it is a piston rattle or liter issue If it is a piston rattle theres not much to do but live with it I'v tried to pull coils one at a time before starting it on 3 separate cold starts.No major difference I thought piston skirt noises,cold start knock were more like a rattle,loud knock??? Can anyone comment on that?? Thanks Chris

VORTECS ARE NOISEY WHEN COLD, THEY ARE A PUSHROD DESIGN, PISTON SLAP IS VERY COMMON IN V8S INCLUDING GM AND ALL OTHER BRANDS IT IS NOTHING TO WORRY ABOUT

05GMCZ71 · May 22, 2011

But But But! I paid $40,000 for my truck! It shouldn't do that! WAAAH WAAH WAAAH!

4wd · May 22, 2011

If all GM cars make the same noise at every and each cold start then it's NORMAL,,,,but but but not all make the noise, those that make the noise have a problem and that's due to the fact that GM decided to produce cars knowing that a certain percentage will have these problems because of the way they assemble engines, this is the result of GM's QA system.

They must fix these problem whenever a customer complain,,,

05GMCZ71 · May 22, 2011

You can't fix something that's not broken.

If all GM cars make the same noise at every and each cold start then it's NORMAL,,,,but but but not all make the noise, those that make the noise have a problem and that's due to the fact that GM decided to produce cars knowing that a certain percentage will have these problems because of the way they assemble engines, this is the result of GM's QA system.

They must fix these problem whenever a customer complain,,,

4wd · May 22, 2011

Okay! if it is not broken then com back to the dealer after warranty expires and ask the dealer to check the noise, and let' us know what they say...

jro909 · May 22, 2011

Okay! if it is not broken then com back to the dealer after warranty expires and ask the dealer to check the noise, and let' us know what they say...

oh how people like you make my head hurt, i'm going to say this once more VORTECS ARE NOISEY ITS A COMBINATION OF ALUMINIUM SKIRTING ON THE PISTON HEADS THAT NEEDS TO EXPAND WHEN COLD, OR THE VALVES/LIFTERS A PRICE TAG DOES NOT DETERMINE IF ITS PERFECT, YOU SOUND LIKE THE KIND OF GUY THAT NEEDS TO INVEST IN A BENTLEY I HEAR THEY ARE PERFECT BECAUSE THEY ARE A COUPLE 1,000,000 DOLLARS.....