2020 Silverado 3.0 Diesel Exhaust Falling Apart

[Sqrls]

I have a 2020 Silverado Crew Cab with the 3.0 diesel purchased May 2, 2020. I currently have 20,800 miles on the truck. Since about 12,000 miles I’ve had an exhaust rattle that sounds like heat shield rattle, but has been getting progressively worse (intermittent DEF errors as well). Initially the rattle was intermittent and I could not see any contact with the heat shields, so I put copper RTV along the suspect looking welds on the DPF/SCR and exhaust clamp thinking it was an exhaust leak (it is, you can see where the exhaust leaks blew out the RTV). This did not help the sound and it was getting worse over time. So I put straps around the exhaust isolators to tighten them up. This helped for about a week or two, so I removed them. It has now gotten so loud, it sounds like the exhaust is about to fall off from a mile away. When I get under the truck, if I grab the Exhaust flex connector with my hand, the sound instantly goes away. So I put two Mishimoto clamps around the flex connector (one constant tension clamp). This pretty much got rid of the noise except for occasionally. If I remove them, everyone hears me in a mile radius. I would be fine with just keeping these clamps on, but in my state of Virginia, this means my new $56,000 truck will not pass safety inspection. 
The obvious solution would be to make a service appointment for an obvious warranty issue. However, three different dealers in my area have told me I need to pay a $108 diagnostic fee before they even look at it, that it won’t be covered under warranty, that diagnosis will take 12-48 hours, and that while some hacks are ‘diagnosing’ my truck, they do not provide loaners, but I can rent a car from them for $28/day. 
So pretty much I have a brand new $56,000 truck that I cannot legally drive in my state and would have to pay to fix. Has anyone had any similar experiences or know my best course of action to get my truck repaired? Should I file a complaint with the EPA to maybe get their attention?

[steve841]

My first thought:  Have it fail the emissions test.  GM then has to cover the fix under the emissions warranty.

[redwngr]

Not sure if this helps your cause, but seems there are some with a clamp issue...

 

https://gm-techlink.com/?p=13781 

 

Particulate Matter Sensor Protection Tube Performance Diagnostic Setting False DTC

October 13, 2020

The particulate matter sensor protection tube performance diagnostic may set a false DTC P1488 (Particulate Matter Sensor Temperature Circuit High Voltage) on some 2020 Silverado and Sierra trucks equipped with the 3.0L Duramax diesel engine (RPO LM2). The Check Engine MIL also may be illuminated.

If the vehicle has DTC P1488 set, check if the particulate matter sensor is loose in the exhaust pipe. If the particulate matter sensor is loose, follow the diagnostics in the appropropriate Service Information.

If the particulate matter sensor is properly torqued and DTC P1488 is set, test the exhaust for leaks using the GE-52250 Power Smoke Diagnostic Leak Detector. Since the sealing bladder cannot be installed in the tailpipe upstream of the exhaust cooler, it’s recommended to use duct tape to seal the cooler.

Repair any leaks as needed and replace the particulate matter sensor.

If the joint shown is leaking (Fig. 23), the clamp may have bottomed out before sufficient clamp load was applied to the joint. (Fig. 24) The clamp should be replaced if this condition exists.

 

Fig. 23

 

Fig. 24

 

Refer to #PIP5748A for additional information.

[Sqrls]

The clamp is pretty much the only

part of the exhaust under the truck that’s NOT leaking .

 

I’ve figured out where the problem is so currently that’s not my issue. My problem is getting it repaired under warranty without having to pay to repair my 6 month old truck. I can weld on an exhaust pipe for cheaper than the dealer wants just to look at it. I would rather spend $108 towards filing a federal lawsuit against GM so they can pay their lawyers more than pay for a dealer to just look at it... One dealership literally told me, “ the bumper to bumper warranty doesn’t cover everything so I will also need to pay for the repairs (without looking at it). 
 

Dealing with Chevy service is probably why I will never buy a Chevy again regardless of how much I like this truck. I just want to figure out a way to get it fixed under warranty without having to pay for their parts that failed. I thought that was the point of the warranty. 

[leverett.scott]

I've never paid a diagnostic fee if it was warranty work.

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[newdude]

You never pay diagnostic fee unless it goes customer pay or out of warranty.  We make it clear to people that if its not covered, they would then owe the diag fee.  They can't get the money up front for something they haven't even touched yet. 

 

Being the part in question (exhaust pipe from the clamp back) is not emissions or powertrain related (no emissions components in the exhaust on the 3.0 after that clamp) it would be covered by your 3/36 bumper to bumper.  Try starting a case with GM Customer Service and they may be able to get you to a good dealer.  

Edited December 9, 2020 by newdude

[ericarenee]

Maybe they are explaining the Diagnostic fee incorrectly. Some of the places such as the Tool Repair shop. Small lawn and yard equipment ships. Where we get our tools serviced at. Charge you a upfront Diagnostic / Hour Labor fee when you drop off the item for repair even if you have warranty on the item. Once they determine its a warranty covered repair they will give you your Diagnostic fees back . This is to insure you do not just use there services to find out what is wrong then take it someplace else or make the repair yourself after they tell you what is wrong for free.  

 

The Shop and  dealership i use for cars you sign a form when you drop it off that says your responsible for diagnostic fee unless its covered by warranty . I never seen a dealership charge you these fees up front as they have your Vehicle and require you to pay if any money is owned before you can retrieve your  Vehicle.. 

I would  call dealership again and verify  there exact policy . if they are asking you money to drop it off  then maybe call GM Advisor to get them to help you out.. 

most important thing DO not work on or try to correct the issue yourself. 

I own a Home Renovation Company. Occasionally we will have something go wrong. a LEAKY Faucet  or broken light switch to a door not latching  perfectly. My warranty  states very Clearly  . We are to be called immediately when there is any issue , If the customer tries to make any REPAIRS They own the problem if it cost us because of there Workmanship for trying to fix themselves . 

 

Just my Two cents... OHH you can get further being nice then  threatening  lawsuit. 

 

Good Luck..  

[mookdoc6]

Yeah...under warranty?  Take it to dealer don't touch it!

[BlaineBug]

If the truck is under warranty you do NOT pay a diagnostic fee.

[RyanbabZ71]

Find a new dealer [emoji2361]


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[BlaineBug]

You can also attempt to contact a Chevrolet Executive Resolution Liaison at 855-880-1400.  Tell them about your experience.

[Sqrls]

19 hours ago, BlaineBug said:

You can also attempt to contact a Chevrolet Executive Resolution Liaison at 855-880-1400.  Tell them about your experience.

Thank you. I will try to do this. 
 

I tried being nice with the dealerships. There’s a reason every 2 years when I get a new truck, it’s never locally for an extra $5,000+. The dealerships within a 150 mile range are all shady as hell. 
The clamps I have to quiet it down are completely removable. I do not buy new trucks so that I have to walk or pay out of my pocket for a rental, especially when I can’t even actually make an appointment for it to be looked at. The appointment is to drop it off, they’ll look at it when they get around to it (according to them, they probably won’t look at it same day). 
 

I have never had this crap with any Dodge, VW, Jeep, or Land Rover dealers. With any of those brands, they are not worried about telling me that I’m not covered under warranty before seeing the vehicle and have no problem providing a loaner while they diagnose and fix whatever issue.

 

Hopefully calling GM will yield better results even though it’s ridiculous to begin with. 
 

[BlaineBug]

2 hours ago, Sqrls said:

Thank you. I will try to do this. 
 

I tried being nice with the dealerships. There’s a reason every 2 years when I get a new truck, it’s never locally for an extra $5,000+. The dealerships within a 150 mile range are all shady as hell. 
The clamps I have to quiet it down are completely removable. I do not buy new trucks so that I have to walk or pay out of my pocket for a rental, especially when I can’t even actually make an appointment for it to be looked at. The appointment is to drop it off, they’ll look at it when they get around to it (according to them, they probably won’t look at it same day). 
 

I have never had this crap with any Dodge, VW, Jeep, or Land Rover dealers. With any of those brands, they are not worried about telling me that I’m not covered under warranty before seeing the vehicle and have no problem providing a loaner while they diagnose and fix whatever issue.

 

Hopefully calling GM will yield better results even though it’s ridiculous to begin with. 
 

It's worth a shot.  I didn't have so much as a bad dealer experience but rather a somewhat rare electrical gremlin.  I believe GM turned the screws a bit to make sure the issue was taken care of sooner than later.  And I was calling in on a used vehicle I bought 1 year ago with 34,000 miles at the time, not a brand new truck.  Covered under warranty doesn't care which owner it is!

[bshort]

Complains about a truck being 56K and then proceeds to smear orange silicone all over it and okie-fy it with a hose clamp.  Maybe try bailing wire and bubble gum next?    In all seriousness, straight dealer trip for warranty....zero out of pocket.  Side note:  If you didn't buy local, you often do not get priority service from the local dealer.  They will get to you, but generally will not part the seas for you.  

[aemeott]

I am experiencing this issue currently. I am at 91000 miles and the expansion exhaust pipe must have cracked inside the wire mesh where you have clamps and is allowing a strange resonance. The dealer claims they have not seen it and the warranty will not cover exhaust since I am over the bumper to bumper. I recently just had a code P2C7A which is more than likely oxygen being detected causing the light. I am going to get the expansion pipe section replaced and then get the code checked out to make sure it isn't something else in the emissions system failing. I have about 9000 more miles of warranty for that equipment. It is frustrating there is apparently an issue and we have to pay for it.  I am posting this for someone else suffering from this failure.