Unbelievable…
Do I have any recourse to sue the original owner, in the event I discover that he was aware of the bad engine? I am calling Dallas Mercedes’ to ask.
Also, can you explain to me how it is that my mechanic can be so sure that the previous owner had the engine looked at for precisely the same problems?? I’m really curious about that.
This is a very slim to low likelihood of going in your favor though based on previous experience.
The car makes a knocking noise.
It was producing smoke out of the tailpipe but that stopped when my mechanic changed my spark plugs and a coil and oil separator. Likely it’ll come back though.
I’m not going to buy the new engine from MB. I don’t really want to by a used one, especially not after what I’ve been reading about the cylinders in this engine, I think I’ll just have the same problem again eventually.
It’s just a mess.
In the beginning I was SURE it was a transmission problem. But apparently the transmission is perfectly fine.
if you factor in the labor needed to pull an engine, disassemble it, fix it with new parts and reassemble it to a specification, you’re right out the $26,000 cost of a new engine from Mercedes, inclusive of the labor to reinstall it. Unfortunately these engines aren’t really rebuildable in the sense that there are a lot of parts available for them in the aftermarket, so you’re stuck selecting from the dealers inventory which is always going to be new, or you’ll have to source a good known used engine from a crashed one through a reseller, and that engine may or may not have the same issue is the one you’re pulling out.
Since I’m not able to get the service history from MB Dallas, there’s no way I’m going to be able to prove the prior owner was aware of an engine problem.
I just have to give up the whole thing. I’ll sell it this week.
makes me so mad.




Last edited by colorado_matt; Apr 21, 2022 at 08:59 AM. Reason: bad wording
In Spring of 2021 I bought a GL550 from a guy (well, sort of, but I’ll get to that part in a minute) in Texas. I bought the car at 60,000 miles “with no known problems”. As of today, Spring of 2022, the car has 70,000 miles on it and Mercedes Benz has told me that I have scoring inside the fifth cylinder and the car requires a new engine, priced at $26,000 not including taxes and fees.
WTF?
That’s basically my situation. I have called Mercedes’ headquarters in Atlanta and was told very politely that there was not jack **** they are going to do, or ever going to do, to help me.
So back up. This is the part that REALLY bothers me. This guy (THIS GUY) who I bought the car from. He had it listed online as a private party sale. He’s in Texas, I’m in Missouri. We talked back and forth and I drove down to Dallas to buy the car. As I left Missouri to go to Texas to meet him, he told me he was going to meet me at X dealership in Dallas and we’d do the transaction there, because there was a technicality/loophole in TX property tax rules whereby he would save a significant amount of money on tax for the car if he sold it to a dealership who would in turn sell the car to me. Fine, I didn’t care. That being said, it ended up being a very long day, very annoying at the dealership, slightly annoying they charged me a fee for the paperwork (and the other guy wasn’t willing to pay for it 🙄
. The guy selling the car was there all day, we both did all our paperwork, etc. Fine. Whatever. We did the deal, I left with ownership of the car. Done.NOW. Since then. Almost immediately, I had to replace the front left air suspension for about $3500. Fine. I did it. Shortly thereafter I had to replace the front right air suspension, another $3500. I also had to replace the compressor, that was about $1000. Fine fine fine. From my reading online, it seemed pretty normal to have to replace the air suspension by 70K. I figured the seller was just a savvy guy……
Now. About six months ago I started hearing knocking, the car would slip upon shifting gears, and then eventually smoke came out the tailpipe (good Lord). I just stopped using the car during this time, kept it in my garage, and drove another. My friend, a mechanic, changed the spark plugs, oil separator, and some coils/line. The smoke stopped but the knocking and slipping persisted with zero improvement.
IMPORTANT: when my friend the mechanic changed the oil separator, he told me that he was absolutely positive this car had been looked at for this same issue before. I am NOT a mechanic, I know nothing about cars, but my friend the mechanic is very knowledgeable and upright, so I believe him. I asked him if he was positive, he assured me he was and that someone had been fiddling around exactly where he was.
Fast forward to this week. Finally bit the bullet and dropped the car off with MB for them to officially DiAgNoSe it. ($600 my ***). Anyway. This is how I found out about scratching inside the 5th cylinder and that I am screwed.
MY QUESTION: first of all, what is going on????!!! Second of all, this hit me today, did this guy I bought the car from, know about the problem, and sold it to the dealership to sell it to me, as a way to shield himself from any liability for prior knowledge????? If so, what can I do????? Thirdly am I just completely wasting my time asking MB HQ to give a **** about this? Fourthly, (lol fourthly, I promise I’m almost done) how can my mechanic be so sure the prior owner was aware of this problem? I’m imagining the mechanic who looked at it previously left an ancient scroll in the engine like “Toby was here, 2020” LMAO but that’s probably not the case…..lol. So, how? I’m truly curious.
Okay car guys. Help me out here. Thank you!!!!!
Hopefully you don’t owe more on the truck than what it’s worth. Once you have exhausted corporate MBUSA and they have shown they won’t help you (they won’t as you’re a third party owner…..perhaps if you were a long time purchaser of brand new Mercedes vehicles they might help you out), I would look at top independent Mercedes mechanic shops in your area and see if they can provide any advice that doesn’t involve spending 20k on a new engine. If that doesn’t pan out then yes cut your losses.
This unfortunately is a learning experience. DO NOT purchase any Mercedes or German make or heck any Luxury vehicle unless it is under factory warranty or Certified Pre-Owned warranty and extend it out as far as you can.
I came from a 2013 Lexus LX570. It had issues even the Lexus dealer could not figure out. They pretty much threw in the towel and said it was normal. Steering wheel twitching and vibration at highway speeds even after spending $6000 on a whole new front suspension with new tires and multiple alignments is not normal! So don’t think that Lexus is problem free. My history with Lexus is poor! I sold it and bought a 2017 GLS550.
Mercedes is light years ahead of Lexus when it comes to technology and driving dynamics. My LX570 got 13 mpg with a super small gas tank. My GLS550 gets 18+ same commute and is MUCH more powerful, handles better and is fun to drive. Nothing with 3 rows is as solid or drives like it!
I bought CPO and extended additional 2 years giving me 3 years of total coverage. Who knows what the future holds after that but my GLS will be paid off before then and if it needs a new engine at that time I’ll weigh the costs.
Wish you the best in whatever you decide!
The Best of Mercedes & AMG
anyway, prior to selling, i got a low coolant warning which turned out to be a cracked coolant hose. no problem, i spent $450 to fix that and flush and refill the line. we were also due for a major "B" service+ (new spark plugs, etc), tires were balding on inside and needed replacement, new brake pads and alignment recommended. nothing out of the ordinary given its age and mileage. at that point, i decided to take advantage of the used car market values and sell it and upgrade.
i sold it without knowing of any other defects or potential for engine breakdown. after the sale, i looked at vroom's inventory and found my car and downloaded the carfax report (free) and it noted all the services i had done on the car, including the very recent coolant hose repair. so maybe if you can get a copy of the carfax, you can see if anything related to the engine issues was inspected and/or repaired in the past ... i believe it's not free unless posted by a seller, so it may cost $29 or something to download.




Pre 2015 GL450-550 have same 4.6l V8 m278 engine. Different boost levels on turbo.
Both start going out at 70k miles - just a design of pistons.
6.3 has 5.5l V8 m157 engine with similar design - different stroke and piston diameter.
To answer question about rebuild - yes sure it can be done but not on the budget. Just let this car go and move on.
Mercedes M278 Engine Problems and Reliability
Early build M278 V8s had some problems with the timing chain tensioners causing a rattle on start up. The engine has a pretty complicated timing chain drive arrangement. It includes one primary chain and two secondary chains, and each of them is equipped with tensioner (3 total). If not pay attention to knocks/noise for a long time, this may lead to the replacement of the entire chain drive system together with cam adjusters. There were some reports of engine oil starvation due to the failure of the oil pump drive gear (oil pump is driven via a chain).Also, there were some problems with premature valve guide wear, but later engines don't have that issue. The Silitec coating showed themselves as bad cylinder surface material for operation under high temperatures and detonation. Later, the manufacturer switched on NanoSlide coating which is more scratch resistance.
According to this article the GL63 might have Nanoslide cylinder liners.
https://www.motorauthority.com/news/...on-engine-tech
To the original poster. Stinks to be in your shoes. You did roll the dice with a used car and got burned. I don’t understand the slipping comment. But regardless keep in mind new cars are big money fixing might be worth consideration, but if not mechanically inclined or have no time frame for the vehicle to be torn into pieces, the best bet is to sell it with a broken engine for a fraction. Some savvy mechanic will pick it up and put a used engine to get it going or a salvage yard will pick it up for parts at the auction.
https://emercedesbenz.com/autos/mercedes-benz/s-class/mercedes-benz-new-v6-and-v8-engines-are-more-powerful-and-more-efficient/
https://group-media.mercedes-benz.co...l?oid=14316637
Last edited by Ricardoa1; Apr 22, 2022 at 08:11 PM.




Oil starvation is because some one decide to use oil pump with variable capacity. That electric connector underneath your crank pulley is a control valve input for oil pump variable geometry. Only reason you starve is because your electric circuit goes south.
Nanoslide - not a solution to your problems, let's say those problems is not surfaced yet. Couple weeks ago someone brought ATV cylinder to machine shop i do work sometimes to have it honed, long story short - the coating is so thin that after one hone pass it needed a cylinder sleeve. So goes your 2k aftermarket boost ad, where they are not responsible for engine failure.
Valve guide - another bed time story. Is it all legal conversation to avoid class law suits... You can say - we used not so good parts supplier to manufacture exhaust valves for our "race" engine which become overheated and loose seal, run a buyback, etc, big money expenses, or just say - oooo valve guides just had wear, it happens, so deal with it yourself... Meanwhile at 50 dollars a piece they could of manufacture inconel valves with lifetime warranty...
Only one to blame for piston wear - is piston supplier.... kolbenschmidt or whoever. Side skirt coating is about 0.0005 inch thick. is about any regular coating thickness, last about 70k - statistically. Could of make 0.001 thick - would last twice longer.... But guess what - they need to eat too... By the way - there is a way to machine Silitec blocks - using PCD cutters. After that hone it with corundum stones, put repair pistons and go... However no one is interested to sell oversize pistons for these engines... Simple economy...
For the woman who wrote original post - that POS guy pull some sneaky move on you. First time i hear about middle man dealership. He knew exactly what was going on with the engine. So he pulled a strings to let it go and avoid liability.
The little knocking noise was present very shortly after I bought the car but I didn’t care because I didn’t know and my CEL wasn’t on.
i just talked to MB Dallas and they said they are legally not allowed to give me any information on the service history of the vehicle while it was under the previous ownership. Is that really so????
If they refuse, you could get in contact with MB customer service, they will do it for you.




Last edited by olcree1111; Apr 24, 2022 at 09:24 PM. Reason: spelling
A few things can cause the issue, but once it has started, there is no going back.
It sounds like there was an oil distribution problem at some point, around the time you had the Airmatic struts replaced.
The slippage you experienced was likely caused by reduced power due to problems producing compression in cylinder 5, causing the piston to rub against the side of the cylinder and caused the knocking sound you experienced.
It is possible to have the engine block worked on and the cylinder rebored, but it would require new pistons too, so would be costly and is unlikely to last very long without much greater frequencies of maintenance. the tolerances required are incredibly tight. MB, like any other OEM would prefer to replace entire component groups instead of individual component parts due to the lower amount of potential human error and time required ~ as they have to offer warranty on those parts and the labor ~ much like with your Airmatic struts, they replaced the entire suspension stacks instead of just the internal airbags.
Buying any used vehicle of this age is a risk, and without your own working knowledge of the vehicle, it can become very costly when relying on OEM or third party mechanics, especially with European vehicles.
Like many have said, may be best to cut your losses and sell the vehicle for the 18k you have already been offered, but it depends if you are more concerned about finances or driveability ~ I would personally prefer to try find a good condition second hand motor block to replace the scored block so that I could get the car up and running for use, or for resale.
At least the first 5 years of your cars services will be on record with MB ~ call a service center and ask for the emails/printouts ~ as you are the legal owner, they will give it to you. As they do not provide physical paper service books anymore, they are legally obliged to offer you this information about the service history. But given its age, I highly doubt that its most recent services have been with MB, and that is where the information you want would be,
Last edited by JayMwang; Apr 25, 2022 at 07:04 AM.








A few things can cause the issue, but once it has started, there is no going back.
It sounds like there was an oil distribution problem at some point, around the time you had the Airmatic struts replaced.
The slippage you experienced was likely caused by reduced power due to problems producing compression in cylinder 5, causing the piston to rub against the side of the cylinder and caused the knocking sound you experienced.
It is possible to have the engine block worked on and the cylinder rebored, but it would require new pistons too, so would be costly and is unlikely to last very long without much greater frequencies of maintenance. the tolerances required are incredibly tight. MB, like any other OEM would prefer to replace entire component groups instead of individual component parts due to the lower amount of potential human error and time required ~ as they have to offer warranty on those parts and the labor ~ much like with your Airmatic struts, they replaced the entire suspension stacks instead of just the internal airbags.
Buying any used vehicle of this age is a risk, and without your own working knowledge of the vehicle, it can become very costly when relying on OEM or third party mechanics, especially with European vehicles.
Like many have said, may be best to cut your losses and sell the vehicle for the 18k you have already been offered, but it depends if you are more concerned about finances or driveability ~ I would personally prefer to try find a good condition second hand motor block to replace the scored block so that I could get the car up and running for use, or for resale.
At least the first 5 years of your cars services will be on record with MB ~ call a service center and ask for the emails/printouts ~ as you are the legal owner, they will give it to you. As they do not provide physical paper service books anymore, they are legally obliged to offer you this information about the service history. But given its age, I highly doubt that its most recent services have been with MB, and that is where the information you want would be,
Last edited by Ricardoa1; Apr 25, 2022 at 01:46 PM.





