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Knock Knock….It’s Your GM Engine Knocking

June 07, 2012 By: LemonLaw Category: cadillac, chevrolet, engine knock, GM, gmc

It’s a problem we have seen for over a decade– a piston slap and engine knock on cold start with various General Motors vehicles. Now, the latest technical service bulletin is out and it includes 2012 models as well.  Here’s a copy of the TSB courtesy of our friends at pistonslap.com (website no longer available, links removed).

The most current models affected are 2007-2012 Cadillac Escalade, 2007-2012 Chevrolet Silverado, 2207-2012 GMC Sierra, 2007-2012, GMC Yukon Denali, and the 2007-2012 GMC Yukon XL Denali equipped with the 6.2 liter engine.

According to the TSB, the noise may begin in the first 12,000 to 15,000 miles and lasts between 5-30 seconds.  The noise is more noticeable when the weather is below 50 degrees.  The engine knock may be caused by an interaction between carbon that has formed on the piston, the piston motion, and the cylinder wall.  GM engineering feels that this engine knock or piston slap is not detrimental to the vehicle.  We are not so sure of that.

If you have been repeatedly for your General Motors engine knocking, it is essential that you look into your rights under State Lemon Laws and Federal Warranty Laws.   You could be looking at recourse and the help is free.  Contact a Lemon law Lawyer in your state for more information.


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44 Responses to “Knock Knock….It’s Your GM Engine Knocking”


  1. #1 LemonLaw says:

    @Brian: If you go to http://www.lemonlaw.com/rid.html, we will be glad to review your claim free of charge to see if there is something we can do.

    • #2 Derrick Tillison says:

      I have a 2007 Escalade that’s paid for, the engine knocks real bad. What’s me recourse. Please help.

      • #3 Mike Bresnock says:

        72,000 miles engine noise until engine is warm….sounds like ticking then goes away. Particularly noisy in cold temps.

        I would like to have this fixed!

        • #4 Devon says:

          I have a 2007 GMC Denali with a bad engine knock what can i do.

          • #5 Brian Camp says:

            I have a 2007 Denali that knocks heavy at start up in any temperature. After the knock dissipates a ticking is noticable during slow and medium acceleration. The tick be ones more rapid as speed increases.

            • #6 Mark says:

              2011 GMC Sierra 6.2 engine, bought used with 50k miles, paid cash, engine knocks especially at cold temps, truck surges at stop signs and intersections.

              • #7 Mark says:

                I have a 2007 Denali with 102k miles and it doesn’t matter what the temperature is outside my truck knocks for the 1st 15 to 20 min before going away……

                • #8 William andrews says:

                  My 07 escalade ( 6.2 L ) has a sever piston slap . Started about 58,000 mi. .After three trips to the Caddy dealer in Pgh. and many calls to G M C I have learned they are very aware of this but no call back . I now have 90,000 mi. The slap has turned in to a violent knok @ all temp. .I have owned GMC all my life , always got 265,000 to 325,000 mi. before selling or trading in . I am a professional engine builder . Now @ 70yr. old. I no longer can do my own repairs .I finially got my wife & I abeautiful

                  • #9 Vic says:

                    I own a 2007 Cadillac Escalade EXT. I am having the same cold start piston slap that does not go away in tell the engine reaches normal operating temperature. Even at normal operating temperature I can hear a slight knock. Now the fact that GM discontinued the L92 gm goodwrench crate engine and replaced it with a new L92 crate engine part number 19329865.
                    GM says its a new improved version of the L92 has better hyper alloys that don’t expand as much allowing tighter piston to wall clearances.
                    no more knocking is a good thing…GM should make the knocking issue a recall, it’s embarrassing driving around in a fancy Cadillac Escalade EXT….. the flagship of pickup trucks with a knocking noice, a knocking noice that brings thoughts to mind like………wow that noice sounds so wrong on a $75,000 Cadillac, is my engine going to blow up.

                    • #10 mara says:

                      Just reached 71,000 miles on my 07 Cadillac Escalade EXT. I have lost sleep for the past two weeks with this engine knock tick or whatever you want to call it. I have been in and out of the shop and still going without any resolution. I’m hoping to receive some help from people that have same problem. Please help…Freaking out!

                      • #11 John says:

                        I have a 2010 Cadillac Escalade with 64,000+ miles on it. The engine knock started about a week ago and it do not matter what the temperature is outside. Even when the SUV warms to the proper temperature, the knocking is there. The oil pressure is fine so that is not the issue.
                        It is not good riding around in a $75,000 automobile and the knocking announce your coming.
                        What will be the next step to resolve this issue? Any help will be greatly appreciated

                        • #12 LemonLaw says:

                          @John: I would reach out to GM to see if there are any silent warranties for your year, make, and model.

                          • #13 Carolyn says:

                            I have a 2011 GMC Denali paid Cash is nocking bad took it too GMC will not do anything with me to pay my engine but I paid cash for this the same in GMC should take responsibility I’ve read the reports and I’m disgusted i have a 1995 GMC truck have over three hundred and thirty thousand miles on it with no problem

                            • #14 LemonLaw says:

                              @Carolyn: Now I see what you are speaking of. Please contact NHTSA at http://www.safercar.gov to see if there are any recalls or technical service bulletins.

                              • #15 Owais says:

                                Hi, I have a 2008 Gmc yukon denali with 6.2 v8 engine 108500 miles, it knocks at cold starts up for 5 seconds and the noise goes away as the engine temperature comes to normal. What is the next step to solve this problem?

                                • #16 Paul kelly says:

                                  I have a 2013 Silverado with 31,000 mi.
                                  Sounds like a thrashing machine for about 5
                                  Minutes. After start. The dealer agrees something
                                  Is wrong but Gm won’t do anything.

                                  • #17 Brandon MacKinnin says:

                                    ’07 Yukon Denali. Came from California. Engine knocks when cold for 5-10 minutes. Has 155,000 miles on it.

                                    • State: Alberta Canada
                                  • #18 Benjamin J Liell says:

                                    2008 Yukon Denali with 6.2 and piston slap. Not the original owner, just bought it.
                                    Any recourse?

                                    • State: MI
                                  • #19 Rob Mcgonigle says:

                                    I have a 2010 silverado that sounds like a diesel it has 35000 miles I just paid 20000 for and I think I’m going to let them take it back I’ll just continue driving my 04 silverado

                                    • State: Pennsylvania
                                  • #20 Shawn says:

                                    2012 GMC Sierra 1500, 11,000 miles started hearing ticking/knocking on start up, it lasted about 15-30 sec. the local dealer said it was normal, for louder and longer around 25-30k miles, brought to the same dealer, they said the same thing, I’m hit 60,000 mile, brought it back to the dealer, they told me it was carbon buildup, they did a carbon clean and told me to drive it for a 1,000 miles. I drove it as they said, still making the noise, I brought it back to the dealer now that it’s out of warranty they told me the engine needs to be replaced for $7,000 plus dollars. Real nice GMC

                                    • State: Ct
                                  • #21 T.B says:

                                    I have a 2012 Serria Denali 6.2l the engine is knocking took it into a shop they said it was the timing chain when I took it to another shop to double check they told me it’s a commen issue with these engines. GM knows about the engines being shitty and won’t do anything about. No recalls on them either.

                                    • State: Saskatchewan, Canada
                                  • #22 Frightened says:

                                    2012 Denali here, same problem <60k miles. I'm very concerned.

                                    • State: NY
                                  • #23 James says:

                                    2013 Sierra Denali 1500 6.2L 57000 knocks at any temp until the engine warms up. It is worse when the temp is below 50 degrees. The dash is also cracked. This GMC has been nothing but a disappointment!

                                    • State: SC
                                  • #24 Jerome Sterling Hicks says:

                                    2008 yukon xl slt 5.3L with a tapping lifter, right after 2k in transmission , 800 on bad electrical wires, 1200 on both axles , cv seal rotors and brakes, and now the tapping, and of course its paid for…thx GMC for your long lasting junk! Ford, Toyota, Honda will get my money from here on, i have been a GMC owner since 1987, really disappointed in America’s foremost auto manufacturer.

                                    • State: Maryland
                                  • #25 Juan ibarra says:

                                    I have a 2007 Escalade , it has a nosie knock at cold start , it will knock for about 2min then it will go away , I just ran out of factory warranty what can I do

                                    • State: Texas
                                  • #26 Tom Royal says:

                                    2007, Piston Slap like everyone else, very embarrassing. I don’t even like to move the truck in the mornings.

                                    • State: MD
                                  • #27 blake says:

                                    Same here, any help makes it hard to sell……

                                    • State: mi
                                  • #28 Chris Kelliher says:

                                    I own a 2008 Denali 6.2, we purchased the vehicle with 35,000 miles we now have 138,000 miles. The engine has always ticked until it warmed up every day, every start cold in morning in a heated garage in winter or cold start in summer. Mention to dealership and was told its normal and that if it goes away when warm not to worry about it so we live with it to this day. Have been looking at rebuilding the engine and keeping vehicle because its in great condition. every time I start it I’m reminded of the noise.

                                    • State: South Dakota
                                  • #29 Mike Krzesowiak says:

                                    2011 yukon denali xl 6.2,,engine knocks bad for about 10 mins until warm,,truck has 83,000 miles,please help get this fixed!

                                    • State: MICHIGAN
                                  • #30 Nathaniel Jones says:

                                    O7 cadillac engine ticking piston slap ing dam Cadillac help

                                    • State: GA
                                  • #31 Shannon Jacque says:

                                    2012 Yukon Denali. I purchased this vehicle used four months ago. The engine started knocking, so I limped it over to the dealer that is saying it needs extensive engine repair or an entirely new engine. It has less the 100,000 miles, but is just outside the 5 year powertrain warranty. GM is not wanting to help with repairs. Anyone else have this issue?

                                    • State: TEXAS
                                  • #32 Brittney says:

                                    We have the exact issue. 2010 yukon denali xl. 89000 miles. Bought it used one previous owner. Regular oil changes. Drove it to work one day and the rattling started. No previous issues except for the auto start on occasion. Brought it back to the dealer who told us the exact same. Told us 3 grand for the engine fix and I’ve read multiple others with the same issue. Why is there not a recall on This? We had the thing 6 months now we owe over 26 grand on a vehicle sitting in the driveway ruining our credit because we had to get a reliable vehicle. Gm needs to know they are ruining lives and people have families to take care of. We shouldn’t be worrying about how we are going to pay for something that is clearly a gm issue with multiple other vehicles/consumers.

                                    • State: Il
                                  • #33 Dboy says:

                                    I️ have a 2013 Cadillac Escalade platinum edition bought it a month today drive fine till this morning it made a knocking noise upper on motor all fluids are fine oil pressure everything paid 35k at a Chevrolet dealer sold as is no warranty and I️ called them back they said pay a inspection fee and that all they could do it makes me mad because they ddnt offer to tow it or nothing and if it’s something I’m out of pocket can’t trust no dealer no more wish someone can help what do I️ do if it’s the motor do I️ just take there junk back and don’t pay nothing it’s stressing

                                    • State: Tennessee
                                  • #34 Valdez says:

                                    2018 Silverado.2768miles.5.3…only have had a month … missing n light knock, taking it to dealer tomorrow….

                                    • State: Tx
                                  • #35 Silas Magee says:

                                    We live in northern Vermont bought the truck new 2012 Chevy Silverado crew cab All Star Edition Z71. At the end of the day all I’ve done with her on these harsh Vermont dirt roads oil changes and a brake job and tires period while getting new tires though I was pleasantly surprised that after three and a half years of beating the truck on dirt roads in Northern Vermont my alignment was still within specs. The funny thing is I made a video this past winter the truck being 5 years old at how quiet it was idling in the front yard and this was sub-freezing temperatures in December probably single digits. Not shortly after that I’ve noticed the engine tick or slap or knock whatever you want to call it. And I’m guessing it is what it is because after you let the truck warm up and you drive it for 20 minutes and then you let it idle she is as quiet as can be. Just drove her to Maine she averaged 20 and 1/2 miles per gallon kind of hard to say mechanically she’s not running right. So all in all knock on wood she’s been good to us but it is damn annoying

                                    • State: VERMONT
                                  • #36 Tiffany says:

                                    I bought my 2010 Yukon Denali with the 6.2 engine in 2014. I’ve always heard the slapping sound and had issues here and there. Well, January 2018 had to have all 8 lifter rods replaced, and all kinds of other things. It’s now May 2018 and the lifters have collapsed again. The mechanic is GM certified and knows what he’s doing, I just think I bought a lemon with issues from the beginning. GM needs to take responsibility for this lifter issue. As well as some other common issues.

                                    • State: NC
                                  • #37 Joel says:

                                    I have a 2010 GMC yukon xl denali with 126000 miles. It has loud knocking noise all the time.It gets worse when you hit the gas pedal.

                                    • State: Delaware
                                  • #38 colin says:

                                    I have a 2012 Escalade with 84k miles, eight months out of warranty. Synthetic oil every 5k miles, always premium fuel. Knocking started suddenly brought it into the dealership and found out I was just out of warranty period (time flies). Brought it to my trusted local garage and got an estimate for $2800 to replace all sixteen lifters (or $1800 to do the eight on one side).

                                    • State: TX
                                  • #39 Jarade Purk says:

                                    2007 Yukon Denali 167,000 miles piston slap followed by a rod shooting out the bottom of my motor. Have had this seriously 2 months, ran fine all day then just as I was leaving work to go home started knocking then lost power and a stall which was the final.

                                    • State: IA
                                  • #40 THOMAS says:

                                    2010 Yukon xl Denali 115k
                                    Just dropped #4 lifter. What recourse do I have? Thanks in advance

                                    • State: NY
                                  • #41 Justin says:

                                    2010 GMC Sierra Denali. Knocks loudly at cold start, and gradually gets quieter. An audible ticking still lingers for as long as I drive it thereafter. The ticking increases as I accelerate. Quite annoying to say the very least.

                                    • State: KY
                                  • #42 Leon says:

                                    2012 Denali 6.2 truck nocking in bottom end some where around the transmission 5- 15 min it does that / my 2011 Denali 6.2 did the same so somebody need to fix the problem or recall all 6.2

                                    • State: Miss
                                  • #43 James Brooks says:

                                    I have a 2007 GMC Yukon Denali with 139.000 miles, started to knock two weeks ago, it had a ticking engine noise prior to that. I took it to the Chevy dealership on 10/17/2018 and the service manager told me it’s I GM cam problem with all those vehicles and they (GM) know it , but want recall them, problem bankrupt them.
                                    He said it would cost around six thousand dollars to fix it, and wouldn’t be worth it, would be better to get a new engine, but that wouldn’t be financially good because of the year and miles.
                                    He said a lady has been bringing her 2014 GMC Yukon Denali in for oil change for over two years and it’s been knocking, and she said she will drive it til it stop, and will Never buy another GM product, I agree and will never buy another GM crap myself.
                                    Do we have a recourse, can a class action lawsuit be accomplished.
                                    Please help..
                                    J Brooks

                                    • State: Tx.
                                  • #44 Leon says:

                                    2012 Denali with 80,000 miles reported the problem too dealership about the knocking service manager said he didn’t hear nothing/ it does it at first starts it makes low knock though out the day I use premium gas so I don’t know what to do with it now

                                    • State: Ms

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