Jump to content

Recommended Posts

Posted

Thanks for pointing that out. Our '21 Silverado 1500 (Nov. 2020 production date) was one of the early ones affected and that's a bummer that there still may be vehicles in dealer stock with the same issue. Had I known, I would have bought a 2500 with the 6.6 gas engine instead.

Posted

Does this mean that those of us that already bought a 2021 will have to wait for it to have problems before being repaired?  Or, will there be a recall?

Posted (edited)

That's a lot of vehicles to fix.  But no different than any other recall that affects millions of vehicles.  I'm curious though this issue affects prior generations too.  But apparently it's "especially" awful for all of the 2021 models.  However I do see that the Sierra was excluded? 

Edited by BlaineBug
Posted
31 minutes ago, Muddturtle1231 said:

Does this mean that those of us that already bought a 2021 will have to wait for it to have problems before being repaired?  Or, will there be a recall?

At the moment, yes, you will bring it in when it starts to misfire and throws a check engine code (typically P0300). I have a suspicion that there eventually will be a recall, given the growing scale of the issue, which you can always check for by your VIN number online or they should send you something in the mail if there is one.

Posted
15 minutes ago, Desrunner said:

It references L84 and L87 engines, but not the L82. Why?

Because they are no longer putting the L82 in the Silverado. 

Posted (edited)
2 hours ago, Muddturtle1231 said:

Does this mean that those of us that already bought a 2021 will have to wait for it to have problems before being repaired?  Or, will there be a recall?

 

This will be a VIN specific coverage.  If it will apply to your truck, you'd be able to pull your VIN in the GM recall search to see if its covered.  

 

GM is calling this a Service Update, not a recall.  It expires November 2022.  To start with also, this Service Update will only apply to new stock that has yet to be delivered to dealers.  

 

Quote

 

This service update involves vehicles in dealer inventory only and will expire November 30, 2022.

When this bulletin is first released, all affected vehicles will be in transit from GM. It is very important that the procedure in this bulletin be performed on all vehicles upon arrival at the dealership. DO NOT sell or deliver one of these vehicles to a customer until the procedure in this bulletin is complete an the field action is closed.

 

Dealers must take the steps necessary to ensure that the service update correction has been made to all involved vehicles in dealer inventory before selling or dealer-trading the vehicle, but no later than November 30, 2022.

 

 

 

The customer side of this has not been fully released yet.  Don't go running off to the dealer just yet, if there is a customer portion of this Service Update, it will have a NEW # to go with it as well as possibly being a recall or special coverage, so hang tight.

 

 

2 hours ago, BlaineBug said:

That's a lot of vehicles to fix.  But no different than any other recall that affects millions of vehicles.  I'm curious though this issue affects prior generations too.  But apparently it's "especially" awful for all of the 2021 models.  However I do see that the Sierra was excluded? 

 

Sierra is on the list.  

 

1 hour ago, Desrunner said:

It references L84 and L87 engines, but not the L82. Why?

 

Not sure as to why this is.  The only thing that comes to mind is the fact that the L82 is an AFM motor, only 4 cylinders deactivate and they are probably seeing much less issues.  L84 and L87 are DFM so all 8 cylinders can deactivate, and there has been a strong showing of lifter failure in those two engines.  

 

1 hour ago, crj19 said:

Because they are no longer putting the L82 in the Silverado. 

 

For the 2021 model year, yes they were.  L82 is not in 2022 Silverado/Sierra anymore.  Those are all now the L84.  

Edited by newdude
Posted (edited)

Re-iterating a couple parts from my reply above.

 

This will be a VIN specific coverage.  If it will apply to your truck, you'd be able to pull your VIN in the GM recall search to see if its covered.  

 

GM is calling this a Service Update, not a recall.  It expires November 2022.  To start with also, this Service Update will only apply to new stock that has yet to be delivered to dealers.  

 

The customer side of this has not been fully released yet.  Don't go running off to the dealer just yet, if there is a customer portion of this Service Update, it will have a NEW # to go with it as well as possibly being a recall or special coverage, so hang tight.

Edited by newdude
Posted
3 hours ago, BlaineBug said:

That's a lot of vehicles to fix.  But no different than any other recall that affects millions of vehicles.  I'm curious though this issue affects prior generations too.  But apparently it's "especially" awful for all of the 2021 models.  However I do see that the Sierra was excluded? 

I saw this too.  How can the Chevy 5.3 have this notice but not the Sierra?

Posted
3 hours ago, haider320 said:

I saw this too.  How can the Chevy 5.3 have this notice but not the Sierra?

The Sierra 5.3 and 6.2 is definitely just as susceptible.  Already watched some youtube videos with lifter failure on a brand new-ish Sierra last summer.

Posted
4 hours ago, newdude said:

 

This will be a VIN specific coverage.  If it will apply to your truck, you'd be able to pull your VIN in the GM recall search to see if its covered.  

 

GM is calling this a Service Update, not a recall.  It expires November 2022.  To start with also, this Service Update will only apply to new stock that has yet to be delivered to dealers.  

 

 

 

The customer side of this has not been fully released yet.  Don't go running off to the dealer just yet, if there is a customer portion of this Service Update, it will have a NEW # to go with it as well as possibly being a recall or special coverage, so hang tight.

 

 

 

Sierra is on the list.  

 

 

Not sure as to why this is.  The only thing that comes to mind is the fact that the L82 is an AFM motor, only 4 cylinders deactivate and they are probably seeing much less issues.  L84 and L87 are DFM so all 8 cylinders can deactivate, and there has been a strong showing of lifter failure in those two engines.  

 

 

For the 2021 model year, yes they were.  L82 is not in 2022 Silverado/Sierra anymore.  Those are all now the L84.  

L82 is active fuel management (v4/v8 mode) and the L84 is dynamic fuel management which allows the engine to operate on as few as 2 cylinders, am I right?

Posted
5 minutes ago, BlaineBug said:

L82 is active fuel management (v4/v8 mode) and the L84 is dynamic fuel management which allows the engine to operate on as few as 2 cylinders, am I right?

That sounds right to me but does that mean different lifters as well? I have an L82 without AFM (-$50 credit). Having all 8 all the time… priceless.

Posted

My 2021 is one of the 2021's that does not have DFM.  It's in V8 mode all the time. I wonder if I'll be good?

Posted (edited)
11 hours ago, BlaineBug said:

L82 is active fuel management (v4/v8 mode) and the L84 is dynamic fuel management which allows the engine to operate on as few as 2 cylinders, am I right?

 

Correct.  

 

11 hours ago, Desrunner said:

That sounds right to me but does that mean different lifters as well? I have an L82 without AFM (-$50 credit). Having all 8 all the time… priceless.

 

No.  Same lifters.  Also, trucks built with the AFM $50 credit still have all the parts, just none of it functions.  Think just like putting in a Range AFM disabler/Pulsar LT except its permanent.

 

10 hours ago, haider320 said:

My 2021 is one of the 2021's that does not have DFM.  It's in V8 mode all the time. I wonder if I'll be good?

 

Should be.  Hardware is still in the engine but won't ever have a chance to operate.  Permanently disabled and GM has no plans to enable on those trucks.  

 

14 hours ago, haider320 said:

I saw this too.  How can the Chevy 5.3 have this notice but not the Sierra?

 

Sierra is on the list.  GMAuthority sucks and can't read.  

Edited by newdude

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Latest Articles

  • Posts

    • My house is set at 75. My car at 70. When I have guests the house is at 70. 
    • OK you say you could hang meat but what was the actual temp? One of the AC systems job is to remove humidity that we feel on our body your new system removed alot of humidity as that is were the water comes from on the ac coils and that made it feel colder. 80 degrees with high humidity will feel hot vs 80 degrees with low humidity will feel alot cooler.
    • I was using recirc/max air. Especially if it really hot i start out by lowering the front windows a little with regular ac the go to recirculation after a few and rolling windows up. And it does not have the newest refrigerant. It has per the info under the hood r134. Not the new r1234yf.  
    • tldr; Shade tree mechanic stumped by variable displacement AC compressor.   Not Silverado related, but for my 2000 Camaro SS. I've never really used the AC since acquiring the car a good handful of years ago. I plan to take it on a trip this summer so I wanted to make sure the AC was in good shape. On an 73 degree day in the shop with the car idling I set the AC on "Max", temp set to cold, and fan on hi. The compressor turned on and air turned nice and cold.   I let it run for several minutes but noticed the compressor never cycled off. The engine was up to temperature enough that it began cycling the cooling fans on high. I had a set of manifold gauges hooked up and it was consistently at about 25 psi on the low side and between 200 and 225 psi (warm engine) on the high side. Per temperature charts, the low side is low (should be 30-35) and the high side is a little high (up to 170 per chart). I read the low pressure as potentially being under-charged underscored by a continually running compressor This was also underscored by temp readings of mid-20 degrees at the vents. Not just cold, freezing cold. Switching off the AC but leaving the HVAC fan on high produced a deluge of condensation underneath the vehicle. I was getting ice buildup on the evap core most likely.   The low reading (25psi) concerned me that the compressor wasn't switching off so I swapped out the pressure switch. No change in behavior, still ran constantly.   The AC clutch works fine as it engages/disengages with the HVAC switch on command. The compressor relay is good as I swapped it with two different known good relays just to be sure. Having eliminated that, and the pressure switch, I added refrigerant, thinking the constant run and low "low" pressure were signs of a slight undercharge. Makes sense, the car is 26 years old and it doesn't appear the AC system has ever been touched.   Adding some R134a didn't meaningfully change the low side pressure. And that's when a lightbulb flashed upstairs. While I consider the car "old", it's possibly "new" enough to have a variable displacement compressor. Did some reading and sure enough. Dangit. I don't work on these for this reason.   Adding refrigerant means the compressor will just compensate and won't really change pressures until it's severely overcharged or undercharged. But at least I wasn't getting ice/frost anymore, but instead high 30 degree temps out of the vents. That's more normal, but with variable displacement now I have no idea where my charge level is at. It's probably overcharged now. The high side even with the engine radiating serious heat was never really over about 225.   The static pressure at room temperature is dead on, before and after the charge. Both high/low equalize after some rest.   I'm thinking I'll need to take it to a shop. I want the proper charge level so I'm not working the compressor too hard. The only way to get an accurate charge is to evacuate and then re-charge with the exact amount specified for the system -- at least that's what I'm reading.   Anyone here with modern automotive AC knowledge?  
    • Mine is in the shop for the AC now. While it did get cold after a bit, it would take a while to even start to cool the air at all. Turns out the compressor was bad and cycling. 
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...