Here’s Why The 6.2-Liter AMG V8 Was The Least Reliable AMG Engine Ever Built & Is Now A Total Legend

endless test runs on the racetrack and road tests under extreme condition give AMG engineers the proof this is an engine whose reliability and performance are second to none well I might give you performance but reliability is second-to-none are you kidding me I'm definitely gonna have to disagree with you at AMG what's up everybody welcome back to legit street cars my name is Alex and in today's factory defect video I'm gonna lay it out for you I'm gonna tell you the truth about what I believe to be the least reliable AMG engine ever built the m156 6.3 liter of v8 and if you thought that I was a die-hard Mercedes fanboy up until this point this video may change your mind a little bit now this video is going to be jam-packed with knowledge and information that can help you avoid buying a total nightmare or help you negotiate an awesome deal on an m1 56 equipped vehicle like I just did so if your engine looks like this you're definitely gonna want to stick around because I'm gonna point out all of its a major flaws and defects and no I did not just buy this SL 63 but I think you guys are gonna really like the car that I just bought it's an amazing story cheapest in the country type of deal and because of what I've learned because of my knowledge I was able to save a lot of money on buying this car so as they say knowledge is power and if you guys are into learning as much as I am then you're gonna love today's video sponsor Skillshare comm Skillshare comm is an online learning community with more than 25,000 classes and design business and just about anything else you could think of right now I'm taking an awesome class on guitar for beginners and even though I speak Italian this Italian course looks awesome I value good information that's presented professionally and that's exactly what I find on Skillshare after these classes I'm diving right into a class on diesel engines because you all know how much I love my old Mercedes diesel the best part is Skillshare is super affordable with annual subscriptions starting at less than $10 a month and a Premium Subscription gets you unlimited access to take as many classes as you'd like there are over 7 million people learning on Skillshare today and you can be one of them for free by being one of the first 500 of my subscribers to click on the link in the video chin box down below this will get you two months of premium access at no cost to you guys this is an amazing deal hurry up click on the link down below you have absolutely nothing to lose and everything to gain big thanks to Skillshare for sponsoring this video now let's get to our first really really expensive issue with this engine our first factory defect is really a shame because this wasn't some new AMG technology or anything overly complicated this is the type of issue that would have you saying come on doll come oh my and of course we're talking about the cylinder head bolts every engine has head bolts but in the case of the m156 they would break here are some old-style m156 head bolts you can see the upper shoulder of the center bolt has worn down considerably and they all look corroded one issue with these bolts was coolant would cause corrosion and the bolts would erode away this severely weakened the torque to yield bolts and the heads would snap right off these bolts also originally used a torques head so the material at the head of the bolt is reduced making it weaker the head bolts were revised by Mercedes but it took about four years for them to implement the changes at the factory this shows the old versus the new and as you can see the revised bolt on the right has more material up top making it stronger and the new bolts didn't corrode like the old ones did either your first indication that you have a broken bolt or two is a low coolant light basically you'll have an uneven torque of the cylinder head this will allow coolant to see past the head gasket and into the combustion chamber you'll also get a misfire because you're now burning this coolant if you let this go eventually you could have a hydraulics situation so this is a very serious issue and it affected a lot of these engines now there is some good news in all of this well sort of it's kind of a silver lining I guess but like I said mercedes-benz and AMG did update these head bolts at the factory eventually and after that update we don't see any more broken head bolts so it seems like they really did fix this problem now what's awesome is that you guys can tell if the engine in your car or one you want to buy is a affected by the faulty head bolts by looking at the engine serial number there is a certain break point where they started implementing the new head bolts so if your serial number is past that then you're good to go so I'm going to leave a factory mercedes-benz bulletin linked down below with some very easy to follow instructions on how you can tell what your engine serial number is and whether or not you have the really really bad head bolts or the new updated awesome head bolts our next major engine issue is not directly related to the head bolts and yes I'm going to be filming for basically every angle of the SL 63 because I don't know where else to stand and talk to you guys so our next issue isn't directly related to the head bolts but if your head bolts were being replaced by Mercedes Benz under warranty they're gonna replace these parts as well because like the head bolts they knew that these parts were gonna be problematic too we're talking about the lifters and I'm gonna start off by saying if you guys do your research online you're gonna see these referred to as many different things they're gonna call them tappets and buckets and lifters and probably a couple other things everybody is referring to the same parts I refer to it as a lifter it sits right underneath the cam lobe and its job is to open up the valve there's a spring that sits inside of it from the bottom so the lifters head issues on the 156 engine normally these are supposed to spin when the engine is running but sometimes they would seize and when that happened the cam lobe would only contact one portion of the lifter and wear it out and because the cams had their own issues by themselves which we're going to get to in a minute it would where the cam lobe out to this is what the top of a seized lifter looks like as you can tell the cam lobe was only contacting one portion of the lifter and it wore it out now this is what the cam can look like after a lifter gets stuck in the head if you have a lifter like this you're gonna hear a ticking noise and it may be loudest at cold start and if it gets really bad the engine will start to misfire this is what a normal lifter looks like and as you can see the circle pattern indicates it's spinning like it should and spreading the contact from the cam properly now mercedes-benz did update the part number on the lifters for this engine but it's unclear if they did anything to improve the lifters some people said they didn't do anything at all others said improve the hydraulic section of the lifter I'm not really sure but if you guys know the answer to that question comment down below and I'll add it to the description box for everybody to see now something you can definitely do to improve the lifters on your m156 is replace them with the lifters out of the EMA one five nine this is the engine that was based off of the one five six and is found in the SLS and more specifically the SLS Black Series lifter has a special coating on it that reduces wear if I haven't completely freaked you out about this engine yet do not worry we still have three more factory defects to cover and we're moving right along with the camshafts this is a dual overhead cam engine so it has a total of four cam shafts which really sucks because each cam is about seven to eight hundred dollars from mercedes-benz and they can fail even if you don't have a bad lifter the camshaft is made of a softer material than the lifter so over many miles and especially if you don't keep up on your oil changes the cam lobes can just wear out looking from up top we have our valve cover and the top portion underneath the valve cover has the intake camshaft and down below has the exhaust camshaft so as you can imagine with gravity more oil is going to accumulate down below on the exhaust camshaft intake camshaft does wear out quicker and more often than the exhaust camshaft and I have a feeling this is because of an oiling issue whether it's people going a little bit low on oil for an extended amount of time or if they're just simply following the manufacturer specific oil change intervals of roughly 10,000 miles I don't really agree with that on this particular engine I'd do it more around 5,000 because the 156 uses a flat tappet design lifter so there's no roller on the top of the lifter to help out with where also I would put a zinc additive in these engines they basically taken that out of modern-day oil but zinc helps with metal to metal friction areas like a cam lobe on a flat tappet lifter there are plenty of these engines that go well over a hundred thousand miles with the original cam shafts so it doesn't affect all of them and I have a feeling those are the people that are really keeping up on their oil changes so in all fairness to Mercedes then they were sued over the issues with the camshaft and lifters and they won so I guess there's no real issue with the camera lifters at all just kidding they probably had really really good lawyers next we have camshaft adjusters and it's interesting to note that all of our factory defects are on the top portion of this engine and that's because the bottom end of the 156 is pretty stout it's pretty strong you didn't see too many issues with the crank rods Pistons or block and they didn't have anything like I don't know rod bearings that needed to be replaced at a normal maintenance interval I mean who would do that so we have our camshaft adjusters on this engine there are four of them they go in the front of each cam and they can change the timing of the camp chef that says variable valve timing a lot of cars have these nowadays but the m156 had some pretty big issues with these guys basically they would fail they would loosen up and they would start to make noise like this you would primarily hear this noise at cold start and it would go away but if these wore out enough they would make that noise all the time and eventually set a check engine light with timing codes so there was a mercedes-benz factory bulletin covering these adjusters but it wasn't as nice as the bulletin for the head bolts the reason why this bulletin isn't as good as the head bolt bulletin is simply because of what Mercedes did or didn't do to improve the camshaft adjuster the bulletin includes every year and every model car that came with this engine indicating that maybe they never really fixed anything in fact we see newer cars 2013 2014 c63 s with M 156 that are still having failing camshaft adjusters now I'll leave the bulletin link down below for all of you to see but it basically just shows you how to check if your adjusters are faulty and as you could imagine these things aren't cheap they're about seven eight hundred dollars a pop as well well we've made it to our last major factory defect with the M 156 engine unless you guys know of anymore if you do please comment down below then we're going to be getting to why this engine is still considered to be a legend now this issue Mercedes has not officially recognized there is no official bulletin but they have updated the part number for these parts like four or five times which isn't always indicative of an issue but in this case I think it is and I'll let you guys be the judge if whether or not seeing this video would totally freak you out if you owned a car with this engine ladies and gentlemen this is why I recommend replacing m156 fuel injectors on a regular interval so what you saw is a stuck open fuel injector what this can do is it can hide roll lock the cylinder it can bend or break a rod at the very least a leaking fuel injector like this can wash out the cylinder so this is a pretty major issue and there's usually not much of a warning when an injector goes out now one video off the internet that's anecdotal evidence but in speaking with a lot of my mercedes-benz dealership technicians over the last few years they've seen a slew of these coming to the dealer now that these engines have gotten a little bit older and if you go on all of the forums all the groups on the internet a lot of guys are reporting injectors that are failing and sticking open so many people are recommending to just replace these injectors that roughly maybe 60 or 70,000 miles especially if this is a car that you really like and want to keep for a long time so with everything I've laid out for you guys all of the big issues with this engine let's go for ride in the SL and I'm going to talk to you a little bit about why I just bought a car with this very engine and why the m156 is a total legend okay guys we're gonna talk performance in a minute but let's talk about what makes the m156 hang at all it sounds let's talk about what makes this thing such a legend and I know I just spent you know like ten minutes totally bashing this engine and if you're an m156 fanboy I'm sure you've already commented about low numbers of failures and blah blah blah blah blah but the fact of the matter is this engine does have a bunch of different problems they're all real problems they didn't affect all of them I totally get this every time I do a factory defect video everyone's like well it was only you know a small percentage not all of them were affected yes I get it there are cars with camshafts that you know 200,000 miles head bolts even with a hundred fifty thousand miles so I'm not saying it happens to all of them but you add it all up it's definitely a lot less reliable than what came out before this and that's why a lot of us were so critical with the m156 was because the m113 K was out before this it's practically bulletproof but anyway an engine with a bunch of problems can still be legendary case in point very similar era the ls7 in the zo six and the z28 they like to drop valves still an awesome legendary engine and for kind of a similar reason so the M 156 is the last naturally aspirated AMG engine ever made ever to be produced they went to turbo charging afterwards and who knows what's next with electric car technology so this is kind of like the last you know just big huge raw all motor you know loves to rev high in each 7000 rpm all day long and it just never stops pulling so this is totally the end of that we're never gonna see it again and if you think about it if we look back at this many decades from now this was the most that mercedes-benz that AMG could squeeze out of atmospheric pressure no assistance from a supercharger or turbo this is it this is what human beings could do the best they could do with an internal combustion naturally aspirated engine from Mercedes of course that could still pass emissions obviously there's real race engines that make more power than this but this this is it this was the best that they could do and it's very impressive if you compare it to the ls7 it was a seven liter engine in the zo6 made 505 horsepower these started in the c63 I like 451 but liked the engine and here not really exactly sure what the difference is maybe exhaust and some tuning but this has 518 horsepower and then the M 159 which is basically the same engine that they put forged rods and pistons that did some of the cam and the intake to dry something they put it in the SLS and the Black Series SLS says 622 horsepower 8,000 rpm redline all motor guides I mean this is just insane and it passes emissions and isn't in a normal it's in a normal Road car so the this that by itself kind of gives it its own legendary status even though it may not be you know it's super super reliable it's like AMG first thought we're gonna build a total all-out race engine then we'll worry about emissions we're not gonna ever worry about fuel economy but we'll think about emissions later and and make it work but I mean the flat tappet design the design of the block there are a lot of things on this engine that are derivative from a straight-up racecar engine so you know I have a lot of respect for the engine itself obviously I think that there are a lot of flaws with it but again this is all like in the top-end so it's I know it's expensive stuff but it's not really like the end of the world as far as you can never fix this stuff which is kind of segues me into why I bought a car with this engine I want to show you guys that you can fix some of this stuff at home and I believe they're kind of like the next really budget AMG car the same reason I bought my e55 it was 9 grand was super cheap but that you know it's a little older styling and whatnot the cars that have this engine they still look pretty modern and this is this is the next kind of realm of super affordable AMG cars so my goal for the car that I bought first off is to fix it it has some issues as you could imagine but I want to build like a 600 horsepower naturally aspirated monster like 7500 rpm revving just eating all the air in its path just would suck up an animal if it could these things sound insane they're probably one of the best sounding v8 ever which also adds to its legendary statuses so that's my goal for that car I'm gonna show you guys some you know some things on how to fix them and stuff kind of take away the fear that I probably just instilled in all of you and showing that this engine can just be absolutely amazing something else this was the first engine that was built from the ground up by AMG before they would take an existing mercedes-benz engine and they would swoop it up put a supercharger on it whatever so they built this from the ground up like I said it's the last naturally aspirated one will probably ever see so it has automatic you know history behind it right there and also it's not really a 6.3 liter it's actually a 6.2 liter and they they called it a 6.3 kind of for marketing it's based off the M 100 from the 60s and I had to look that up I didn't know I'm not like a Mercedes buff but but it's actually a 6.2 you guys probably already commented down below of that family if you compared to the LS seven of the similar area and era it's a 7 liter in the Corvette zo6 that also is the last of the naturally aspirated engines for Corvette for GM they went to a supercharger but this one even in the SL made more horsepower you know with a smaller engine so it just it's squeezing a lot out of it the technology is just crazy the variable valve timing although we had issues you know with the adjusters and everything like that it really made for just a very aggressive and raw engine that you could still drive on the street so a lot of people think the newer ones kind of took away from the soul you know the four liter or the phial 157 that came out after this you know they're awesome engines they make more power and everything like that but you know a lot of people think they're just quieter they've just kind of you know this thing it's just it just wants to eat you alive it is a total riot to drive and again the sound is amazing which you guys are going to hear my car which is like the loudest car I've ever owned but anyway I'm rambling I hope you guys really enjoyed this video I hope I didn't totally turn you off from this engine and I hope that my new videos on the reveal stage and for that are gonna kind of change your mind a little bit on what this engine can be if you know what to expect so with that being said hit the thumbs up button if you like this video share the video subscribe if you're new and most importantly check the bulletins down below don't buy one with old head bolts and I'll see you guys all in the next video [Music]

Channel: LegitStreetCars

Views: 654,037

Keywords: AMG ENGINE, FACTORY DEFECT, LEAST RELIABLE, 6.3 liter engine, 6.3 liter amg, m156 engine, m156 head bolt, legendary engines, c63 amg, SL63, e63 amg, legitstreetcars, MERCEDES, MERCEDES-BENZ ENGINE, RA

Id: Rlj7254gOww

Length: 19min 56sec (1196 seconds)

Published: Sat Apr 06 2019