I am considering purchase of a 2009 SL 63 AMG with 92k miles on it. The car is in very good condition (visually) and service records that are available show the car was well maintained. However, in the first three years the car fax does not show any service records and the dealer (Mercedes) cannot access them so I am told even though I think it was serviced at another Mercedes dealer. So... I am not sure if the head bolt issue was ever addressed with this car. I have asked the dealer to look into it but no answer yet.

Is there a consensus on whether or not this failure of the head bolts can happen at any time; or, if the car has 92k on it and they have not failed, then they are not going to? My heart loves this beast but but my head says be careful. Thank you in advance for your advice.

 

There is no safe mileage-point. If the bolts didn't fail before, failure could occur at 92,001 miles or at 300,000 miles. If you buy the car, you can:
1- Drive the car and enjoy it without fussing about the bolts.
2- Replace the bolts one-by-one. Easy, fast and cheap.
3- Replace the bolts and headgasket following the official repair method. Expensive.

Personally I would not let this be a reason not to buy the car.

Good luck

 

I'm going to live with it, thought I purchased a car that was post problem, but did not check he build date. I've thought of the after market warranty but you will only get up to 40,000 miles and the genuine firms are costly ($6000-$15000) and the cheap one's ($3500-$4500) are at best unreliable and at worst gone when you need them.
64850 miles and counting, I don't have a price from my indie on the replacement cost, he's only ever done one, and the local dealer has never seen the problem, so, its probably less prevalent than some would say.

 

There are some who feel this issue is overblown and others who take a panicked approach to it. Realistically, it's an unknown and unfortunately one without any indicators that a potentially catastrophic failure is imminent.

IMHO, it boils down to your intention with it. I purchased mine to hopefully keep it as a forever-car and went with the optimal solution: complete job with new OE gaskets, upgraded ARP head studs and SLS buckets.

The 1-by-1 method has a track record of working and was the plan for the winter, but my schedule didn't allow it. Currently have two active project cars in my garage so this went to a reputable shop.

If you are able to, pull the valve cover yourself and check. 11 years and 92K miles is a long time...maybe they were already changed.

Unfortunately, mine were original...silver lining is that I verified my cams were perfect, which was a motivator to go with the SLS buckets to protect them.

 

I have both an SL63 at 62k and an E63 at 45k, both in the "danger zone" per build date and both with no history or sign of the head bolts being changed. Both amazing cars, and I would do it again in a heartbeat. I'm a hardcore DIY mechanic and the job doesn't look that daunting, I'm also OCD so carefully monitoring coolant and engine oil levels is just part of my routine. I may start sending the oil into Blackstone for analysis, I've always wanted to try it. From everything I've read it reminds me of the IMS issues on 9X6 Porsches: lots of online hysteria, very low rate of occurrence, but it sucks if you are one of the few.

Let's be real, if spending a few thousand dollars on a repair is a deal breaker, you shouldn't be buying any late model exotic car.

 

Thanks for your comments. I am still considering my options and this is very helpful. I may just buy it and if I need to have some work done so be it.

 

Buyer beware. If you can get one cheap enough, don't mind turning a wrench, and are DIY competent, you can fix most of the issues. It is generally known to be the most unreliable AMG engine ever made. It always kept me from buying an M156 equipped AMG and I've owned two bi-turbo V12 cars and drove them both to 100k+ miles so it's not that I don't take chances. The M156 equipped engines have a much better transmission than the 55/600/65 engines and to some that is worth it alone. MB's 5 speed is as slow as a slug in comparison but very reliable while the 7 speed is , again, much faster but there are some valve body issues that can be expensive to repair. Once you get the turbine speed sensors/valve body replaced, the 7 speed tranny can be very reliable and is much much more responsive than the 5 speed. The M156's power to potential problem ratio was just not worth it to me. Watch this video so you know what to expect from the M156 before taking the leap. It's not all bad as you will see toward the end of the video.

 

Love driving the car, but my headbolts did give way at 66,500, $5000 repair bill….

 

There's a guy local to me selling a 2009 SL63 with a blown head gasket he calls it, for $15,000 with 70,000 miles. I bet his head bolts broke, that's not a bad deal if you can save the engine, if someone wants to buy i can link the ad.

 

Interesting. Please link the ad.

 

Saw it on FB while searching for an R231 SL63

https://www.facebook.com/marketplace...9615774381473/

 

Could be a good deal for a DIY mechanic. Sounds rough though, also has a dent, torn seat, and needs what I assume is the ABC pump replaced. Also very few pictures. On the upside it's a P030 car, at least per the ad.

 

Seems neglected, sadly there are owners like these that just let car get to this point. Good parts car to buy if someone were to crash theirs

 

What's bad is MB put out a product that would fall apart at 70k miles. The things that failed are not listed for any preventative maintenance schedules by MB. Shame on MB not the consumer.

 

Sorry but that's blatantly untrue. I'm really confused why you seem hellbent on spreading misinformation on these forums related to the M156. You post the same ignorance over and over and link to the same video. Are there several potential issues associated with the early engines, of course. But they are also exceedingly rare and in the grand scheme of things relatively easy to correct. I have had a lot of interesting cars over the years, and find the M156 to be one of the best engines I've ever experienced. Probably why it won a number of awards during it's tenure with Mercedes, with some journalists calling it the best naturally aspirated V8 ever made.

 

Ok, I'll bite. What is untrue about my post? Please share MB's recommended service schedule for the ABC system and M156 head bolts at or before 70k miles? The M156 equipped SL in discussion is, as said by another member, a good parts car. Sorry, that's embarrassing for a $100k+ car since there is no recommended maintenance from MB for the failed components. There has been no misinformation spread here. As far as posting videos. I've been a member of this forum for close to 17 years and I've posted the video twice. I didn't make the video and it has positives and negatives of the M156.

The issues are rare? But....there are failures reported in a matter of a few weeks from a very small microcosm of owners on this forum. The issues are rare enough that there was a class action suite against MB years ago on the engine issues. It is also rare enough that owners who know the engines shortcomings are changing the head bolts as a preventative measure. Yep, sounds pretty rare.

Glad you love your M156 equipped SL. That's great. Best of luck to you. I personally love MB's. That's all I drive but I also know what AMG models/years I skipped and why. I have two AMG's and another on the way so, again, big fan here. Judging by the information readily available on this forum, maybe MBWorld should be accused of posting false information?

I guess the word common problems and rare can be used interchangeably:
https://blog.fcpeuro.com/mercedes-be...-common-issues
https://mbworld.org/how-tos/a/merced...roblems-386950
https://oppositelock.kinja.com/ama-a...tos-1791196192

 

What exactly is the disconnect here? MB-AMG should have been held accountable for the head bolt issues.

Those idiotic hollow-torx bolts are used on the entire M112, M112K, M113 and M113K lines as well. However, it was the manufacturing defect with the anti-corrosive coating on a large batch of bolts used in the M156 that finally exposed bad design.

Every single older AMG engine has issues/areas to look out for. Research, prevent, maintain and enjoy.

The real shame is that if MB-AMG put a little more thought/QC into the head bolt and bucket designs, the M156 would have left the factory with a top end as bulletproof as its bottom end.

In any case, this woulda-shoulda-coulda discussion is circular as:
.

1. These issues were corrected on later M156s.
2. Reliability for anyone with an early M156 is easily achieved.

/Topic

 

Enjoy the car for what it is, and handle the bolts as it comes. If your up for it, replace all head bolts, lifters/tappets just for peace of mind

 

Well that was weird. What i thought was a "simple" headbolt failure turned out to be three bolts that were not torqued down properly, causing coolant leak and a godawful mess of black oil with the cams and buckets. They were the old type bolts but had not measurably stretched at all, nor did they look particularly corroded.

 

You post from the position of "guy on the internet" without any firsthand knowledge of the topic, and your statements are over the top dramatic. You copy/paste stuff you find on the internet vs actually providing a real experience. If a new forum user hopped on here to do research on the M156 and saw your posts they would immediately write it off as an option. As the current owner of two M156 cars and the previous owner of another, all with original head bolts by the way, that's a damn shame. I don't deny there are issues, and don't deny that people should be aware. But in your 17 years on the forums I'm sure you've realized that many join forums simply to post about their problems, which tends to over-inflate the perception of the issues. A handful of people posting on here translates to a very small percentage of the overall population, most of which are blissfully unaware of any issues.

I'm a long time Porsche guy and saw the same thing with the 9X6 models which had issues with the IMS which could lead to engine failure. Lots of internet "experts" who loved to copy/paste information about the topic, but had no first hand knowledge of the issue or the cars. Meanwhile I've owned and wrenched on more than 10.

As for how Mercedes should issue a recall, perhaps so. I suspect that the number of failures are still low enough to not put them at risk of a successful class action lawsuit, and maybe below their internal threshold for a recall. Sadly you won't find a European car, especially a performance oriented one, that does not have some potential failure point(s). Fortunately this one can be repaired with relative ease.

 

I apologize if I in someway offend you. Posting helpful links, to the topic at hand, that show there are real issues with the M156 and that future owners need to be mindful that the issues should be addressed is not something that should offend. Maybe my tone was off but yours certainly was. Sharing should not be a bad thing nor should it come with the prerequisite of having suffered personally. If so, most professors would not have a job, counselors would not be able to help others, cops could not identify crimes, and a PHD would have no worth. There are many that come here, post that their car shat the bed, share their experience, and they are off to another car brand never to be heard from again. I don't need to post links to share the knowledge but they are often useful as a reference or to provide additional information.

I joined the forum for knowledge/sharing - how to repair what I have and for future purchases. I'm not an early adopter of new MB engines or technology and would rather learn more about the engines or tech before I purchase. That's not from being cautious; rather, it's from being burned. Again, there is a reason why I buy what I do and I learn from others mistakes. I read the negatives for what they are but, when you see consistent patterns, those negatives starting holding water. Even with the negative comments there is something to learn about the individual or experience. What's the saying - where there is smoke there is fire?

It was apparent many years ago the M156 had more problems than I was willing to tackle or to risk as a daily driver. Then again, that's when they were fairly new and I was not willing to take the chance with a very expensive car that had documented engine issues and not having a supply of engines to swap if I had a failure. It's not the only MB with serious issues but they were apparent early on and it kept me away, at the time, and on to the bi-turbo V12's for performance needs. The M156 engine issues don't make it a horrible engine but it does make them high risk if the problems are not fixed. If those looking to buy can't turn a wrench or afford to spend the additional money to rectify, it may be a bad choice and may make them stay away from the brand after their first experience. Then again, they may never have an issue but I would rather not throw caution to the wind.

To each their own and it is pretty obvious you absolutely love your M156's. As you can tell from my name, I prefer forced induction engines and that's the direction most manufacturers will take until they perfect the charging/storage of electric vehicles to meet the needs of distance drivers. I did research installing twin snails on the M156 since 4 valve heads take very well to forced induction. There is a company out in Cali, forgot the name, that installs twin snails on the SLS. When I contacted them about installing on other models, they declined and told me they only do the installs on the M159 SLS's. It's not that I never considered the M156. Just never considered without forced induction. If an engine is going to have risk of failure, I should get some serious power out of it to make it worthy my while.

Porsche owner here, continuously, for almost 30 years so I too am aware of that brand. Some issues may seem overstated but, even given that, there is still useful information being shared.

 

Thanks for the reasonable response and I generally agree. My only big concern is for the quick Google searcher who immediately finds a negative post and simply writes the car off. Awareness is good, fortunately the issues can be remedied relatively easily and the end result is a really solid motor and a great car overall. Unfortunately nobody makes a bulletproof performance luxury car, particularly not in Europe, so when buying used it's largely a matter of pick your poison. Head gasket/bolts and tappets aren't intimidating to me personally as a DIY mechanic, and if you monitor your car closely (as I do) you'll see warning signs long before a catastrophic failure. I agree it's sad that such effort is necessary, but unfortunately can't think of a comparable model that doesn't also have some potentially expensive pitfalls.