In the exhaust you will see 1 sensor that looks like an o2 sensor near the flex joint. There is a TSB on it actually being loose. There is a second sensor that is not visible, but is located on top of the DPF under the body. You can feel it by hand or looking in the gap from the rear of the truck. This sensor was the one that was loose on my truck. The nut itself was still tight. The weld that holds the sensor to the nut was broken, but the design of the sensor keeps it from shooting out due to pressure. Since I couldn’t get easy access to it, I just put copper RTV in place of the weld then after it cured, patched it with high temp JB weld. No more codes, and it has held tight for 10,000 miles including an 800 mile road trip each way. Having the dealer replace the sensor is probably the best bet, but dealers around here want to charge for warranty diagnosis, act like they’ve never heard of a loaner vehicle (only $75/day rentals), and want to keep the truck for weeks to replace a sensor. JB weld was cheaper, easier, and probably more durable than a defectively manufactured sensor. Dealer can deal with the future issues when I trade it in. The check engine light is probably not from the sensor actually being bad, but from the sensor not providing a consistent reading from wobbling around. The truck uses these 2 sensors and the flow differential between them to determine when a regen is a needed.
Loose oxygen sensor I bet. Either loose in its casing, or loose in threads. At startup, the exhaust shakes it a bit. Once the truck is running, the flow keeps it pinned. Could also be the cat weld broken loose internally. Maybe try hitting the exhaust in different spots, but with a rubber mallet. just a guess.
I live about an hour from the outer banks and have gone there many times. For corolla beach, your truck would probably be fine without even airing down, unless you’re hitting the huge puddles on purpose, but then airing down wouldn’t help anyways. It will go through the sand a little easier aired down. With decent tires like the duratracs, 2wd would probably even suffice except for the really soft spots. That beach is usually well traveled and packed down. Contractors pull trailers through that sand and the linemen power trucks make it through the dunes no problem. The sand in the neighborhood areas is usually softer and more sketchy, but I’ve never had an issue with a stock Silverado with A/T tires. I would remove your lower front bumper air dam though. Otherwise the sand might rip it off. Also keep an eye on transmission temps. The only people I’ve seen get stuck there are idiots who drive into the ocean, and people in CR-Vs and Corollas with bald tires. The ATV pits are also really fun. Some are only big enough for ATVs, but quite a few can fit a Silverado.
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.
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.
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?
+1 on abs sensor or wheel speed sensor. The K2s actually had a recall for faulty wheel speed sensors. The brake wear sensor is actually a dummy light not based on actual pad material left and calculates (guesses) life left from what I’ve read.
Yep if the paperwork was never submitted, it’s still a new truck. I wouldn’t buy it with a replaced motor. There’s no reason for the dealer to take off enough to make it worth it for you. It’s better for them to just sell it to someone else who doesn’t know about the history.
I would stay away. It’s a used truck by definition. No way that is a new truck. It has been registered already and you would be the 2nd owner. Some banks will not count it as a new vehicle for loan rate purposes. Some banks consider any vehicle under a year old and under 5,000 miles to qualify as new. The main reason I would stay away is because that dealer seems super shady (like most Chevy dealers in my experience) and the truck has unknown issues that may leave you without a working vehicle. A lot of dealers nowadays will deliver even out of state free of charge.
I’ve had this error pop up before. Since in Virginia there are no dealers with that can actually check it out within a month, I just kept driving it. It even gave me an error that said 175 miles until speed limited. After a few cycles of driving, the errors went away on their own. I honestly wouldn’t worry about it too much as long as it’s running good. My truck actually ran better when I had the 175mi til speed limited warning and my gas mileage is better than ever currently. I’ve gotten 36-38mpg last 3 tanks of diesel.
Also check cabin air filter. A severely restricted cabin air filter would cause this issue as well. Pretty much for the ac to get cold enough to cause this much condensation on the windshield would require the evaporator temp to be very low from insufficient load.
Preventing mold is definitely not the priority in the design, but efficient air conditioning operation and design shares a lot of the same principles. Mold prevention is definitely a design point. There are quite a few TSBs about moldy smelling A/C that GM has to deal with. If the vent was completely closed, the area under the windshield above the dashboard would be a pocket of hot humid air, especially so in hotter climates. The vent being slightly open greatly increases circulation throughout the cabin. For severe condensation to form with low air flow, the cabin air temperature will be under 70degrees. It would also take quite a bit of run time for the ac to get cold enough to form condensation on the windshield in 90+ degree temperatures. There are other reasons as well from a design standpoint, so there is justification for this design. however, to counter the problem, the windshield would need to be insulated or heated. Otherwise opening a window would also help. Or turning off Max a/c and recirculate.
62 degrees is out of the designed temperature range of operation for pretty much any air conditioning. Yes, you can set it as a target temperature, but pretty much any AC is designed for achieving interior temperatures of 70-80. The reason you have condensation in the pattern that you do is actually due to lack of airflow. However, increasing airflow will actually cause more uninsulated surfaces to condensate on the exterior. The defrost vent being slightly open is actually better for your health. If it was completely closed and running ac at 62 for extended periods of time, it would guarantee mold that’s inches thick on the inside of the vent louvre. The airflow going through it prevents this issue. So the engineers are probably completely aware of this issue and decided to focus on reducing mold growth for 99.99% of users at the expense of convenience for 0.01% of users.
That would be engine and application specific. Usually there is not much pressure in an exhaust system. Also depends where you measure. However, a weld that won’t hold 50psi, won’t hold 1psi. But you will see the pressure drop from 50 to 49 a lot sooner than 1 to 0. Regardless, any leaks in the exhaust contribute to noise and/or rattle in the exhaust note. They can also pull in oxygen and affect readings for various oxygen and exhaust sensors if the leak is upstream of the sensors.
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