Should I Preemptively Replace Headbolts and Valve Lifters?
Thread Starter
Newbie
Joined: Aug 2016
Posts: 8
Likes: 0
GL450 (2012) ; E320 Cabriolet (1995)
Should I Preemptively Replace Headbolts and Valve Lifters?
I have a strong interest buying in a CLK63 AMG with a MY07 or MY08 M156 engine. The headbolt and valve lifter issues make me nervous.
There seems to be a broad consensus that one should preemptively replace the headbolts before problems occur – is this correct, or are there advocates for leaving it alone until the problem presents itself (“Add Coolant”). I would never attempt the job myself, it would be done via a mechanic (I understand cost is around $6k).
Have MB or AMG issued any guidelines or advice on how to address this issue?
What is the part number for the correct headbolts?
Same for the valve lifters – should these be replaced preemptively (perhaps at the same time as the headbolts)? I’ve been told cost is around $2k?
What does MB / AMG say?
What is the part number for the correct valve lifters?
Is the engine otherwise sound? In other words, after I invest the money to correct these issues, will I enjoy years of high-performance, hassle-free pleasure from the engine? Or are there other issues I need to be concerned about?
Many thanks!
There seems to be a broad consensus that one should preemptively replace the headbolts before problems occur – is this correct, or are there advocates for leaving it alone until the problem presents itself (“Add Coolant”). I would never attempt the job myself, it would be done via a mechanic (I understand cost is around $6k).
Have MB or AMG issued any guidelines or advice on how to address this issue?
What is the part number for the correct headbolts?
Same for the valve lifters – should these be replaced preemptively (perhaps at the same time as the headbolts)? I’ve been told cost is around $2k?
What does MB / AMG say?
What is the part number for the correct valve lifters?
Is the engine otherwise sound? In other words, after I invest the money to correct these issues, will I enjoy years of high-performance, hassle-free pleasure from the engine? Or are there other issues I need to be concerned about?
Many thanks!
MBWorld Fanatic!
Joined: Jun 2008
Posts: 8,077
Likes: 2,867
From: Los Angeles
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Replacing the head bolts one-by-one - as long as the head gaskets have not already been compromised - is a significantly cheaper way to do it. Search here, it's been done by a few members recently.
MBWorld Fanatic!
Joined: Jun 2011
Posts: 3,318
Likes: 171
From: Silicon Valley, CA
C63 AMG, P30
I'm in the same boat here so I'm going to chime in.
I did a bit of calling around this past week regarding the "one at a time" method and was advised by almost all that I spoke to to leave it be if/until I do receive coolant low messages.
Reason being this: The techs would advise that while this method is usually successful, they cannot guarantee the head gasket won't leak after the job is done. At that point, it'd be a full heads off job after the cost of the headbolt swap.
It almost made me think that the preventative maintenance could end up opening up a can of worms, even though the chance is small.
Not saying I'm not going to do it, but definitely gave me something to think about.
I did a bit of calling around this past week regarding the "one at a time" method and was advised by almost all that I spoke to to leave it be if/until I do receive coolant low messages.
Reason being this: The techs would advise that while this method is usually successful, they cannot guarantee the head gasket won't leak after the job is done. At that point, it'd be a full heads off job after the cost of the headbolt swap.
It almost made me think that the preventative maintenance could end up opening up a can of worms, even though the chance is small.
Not saying I'm not going to do it, but definitely gave me something to think about.
MBWorld Fanatic!
Joined: Nov 2009
Posts: 4,438
Likes: 388
From: Relocated
2010 Irridium Silver MB C63 AMG Sedan
If you:
1. Change gaskets at the same time
2. Have it done with the complete proper torque specs
3. Have it done in the correct, distributing force order
4. Change all associated bolts with new bolts (for one time torque)
You will not have any issues. It;s honestly not a big deal. Have some one who knows the engine work on it. My guy knows the engine inside and out and has already done several with absolutely no problems after....
Talk to Richard at Autohaus Frankfort in Murrieta...just call him and let him tell you how much of a perfectionist he is. Let him tell you about the procedure. Worth every penny. His shop is like a brain surgeons OR...clean and precise.
1. Change gaskets at the same time
2. Have it done with the complete proper torque specs
3. Have it done in the correct, distributing force order
4. Change all associated bolts with new bolts (for one time torque)
You will not have any issues. It;s honestly not a big deal. Have some one who knows the engine work on it. My guy knows the engine inside and out and has already done several with absolutely no problems after....
Talk to Richard at Autohaus Frankfort in Murrieta...just call him and let him tell you how much of a perfectionist he is. Let him tell you about the procedure. Worth every penny. His shop is like a brain surgeons OR...clean and precise.
MBWorld Fanatic!
Joined: Jan 2009
Posts: 4,563
Likes: 42
C63 AMG
Changing a bolt one at a time is completely fine if done correctly. Anyone that tells you otherwise blah. Just because they are a mechanic doesn't mean they are smart.
Diesel guys do this all the time, BMW has a shop procedure for doing it. Etc etc. If you want them changed have it done one by one with the MB sequence, drop the oil and coolant. Bingo bango done.
If you leave it be, it's a 100% heads off job if that coolant leaks, a member already did that real world test and he couldn't get the seal back.
Just be damn sure you hire someone that knows these engines and ideally had done it before.
Diesel guys do this all the time, BMW has a shop procedure for doing it. Etc etc. If you want them changed have it done one by one with the MB sequence, drop the oil and coolant. Bingo bango done.
If you leave it be, it's a 100% heads off job if that coolant leaks, a member already did that real world test and he couldn't get the seal back.
Just be damn sure you hire someone that knows these engines and ideally had done it before.
Last edited by Merc63; Aug 29, 2016 at 02:21 AM.
Super Member
Joined: Apr 2010
Posts: 609
Likes: 38
From: Arizona
2011 C63
I agree 100% with Merc63. The mechanics are just covering their butts. They haven't done the 1 bolt at a time and they just want to be able to say I told you so if something happens afterwards. Personally I'd rather do 1 bolt at a time then to put on new gaskets. There is a better chance of screwing something up when you replace the gasket. With one bolt at a time, it's pretty darn hard to screw something up.
Trending Topics
Thread Starter
Newbie
Joined: Aug 2016
Posts: 8
Likes: 0
GL450 (2012) ; E320 Cabriolet (1995)
Thanks for all the input, this is a very daunting issue for non-mechanics!
It sounds as though the best bet is to find a mechanic who actually has experience of changing headbolts on this engine, which is easier said than done for those of us away from major metropolitan areas. Are there technical terms for the “one at a time” versus “all at once” methods for doing the procedure?
Are there questions one can ask that will reveal whether the mechanic does actually have experience with the M156 engine, or is just looking to land a high cost job?
Nobody has mentioned anything about the valve lifters – I know the class action law suit went nowhere, but I have read several posts from guys whose engines suffered some pretty severe damage as a result of this issue. Is it another fundamental problem with the M156, or is it just a question of using the wrong oil? Does anyone replace these preemptively? Are there different techniques?
Thanks!
It sounds as though the best bet is to find a mechanic who actually has experience of changing headbolts on this engine, which is easier said than done for those of us away from major metropolitan areas. Are there technical terms for the “one at a time” versus “all at once” methods for doing the procedure?
Are there questions one can ask that will reveal whether the mechanic does actually have experience with the M156 engine, or is just looking to land a high cost job?
Nobody has mentioned anything about the valve lifters – I know the class action law suit went nowhere, but I have read several posts from guys whose engines suffered some pretty severe damage as a result of this issue. Is it another fundamental problem with the M156, or is it just a question of using the wrong oil? Does anyone replace these preemptively? Are there different techniques?
Thanks!
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
MBWorld Fanatic!
Joined: Jun 2011
Posts: 3,318
Likes: 171
From: Silicon Valley, CA
C63 AMG, P30
P/N 156-050-02-25
Junior Member
Joined: Feb 2014
Posts: 35
Likes: 0
2010 C63
The updated 156 lifters are the SLS lifters. They are coated on the tops grey in color. The only other lifters are the SLS BS which are DLC coated all around (black). I had a bad exhaust cam adjuster which turned into worn lifters and cams. I replaced all the cams, adjusters. Put the SLS BS lifters in and while I was there I did the headbolts one at a time. I had zero coolant loss before and after 3,000 miles I still have zero coolant loss knock on wood.
MBWorld Fanatic!
Joined: Jun 2011
Posts: 3,318
Likes: 171
From: Silicon Valley, CA
C63 AMG, P30
The updated 156 lifters are the SLS lifters. They are coated on the tops grey in color. The only other lifters are the SLS BS which are DLC coated all around (black). I had a bad exhaust cam adjuster which turned into worn lifters and cams. I replaced all the cams, adjusters. Put the SLS BS lifters in and while I was there I did the headbolts one at a time. I had zero coolant loss before and after 3,000 miles I still have zero coolant loss knock on wood.
Here's his DIY thread where you can see them.
https://mbworld.org/forums/c63-amg-w...swap-m156.html
MBWorld Fanatic!
Joined: Aug 2011
Posts: 5,351
Likes: 1,677
From: Kitchener, ON
2010 C63 AMG
Senior Member
Joined: Jan 2015
Posts: 425
Likes: 9
From: Eurocharged Orlando
10 C63, 06 S65, 14 ML350, 95 S500
It all depends how you look at it- everyone will have a different opinion: Do it just in case vs wait till something happens.
If I was in your position, I would incorporate the cost in your total purchase price, considering the age and also depending on the mileage of the car. If you do some digging maybe you can find one that already has the updated bolts from the dealership or if the previous owners has records.
Then you also have options on how to attack the situation: go with OEM updated parts or go with aftermarket upgraded parts such as weistec, especially if you plan on doing future modifications.
If I was in your position, I would incorporate the cost in your total purchase price, considering the age and also depending on the mileage of the car. If you do some digging maybe you can find one that already has the updated bolts from the dealership or if the previous owners has records.
Then you also have options on how to attack the situation: go with OEM updated parts or go with aftermarket upgraded parts such as weistec, especially if you plan on doing future modifications.
Thread Starter
Newbie
Joined: Aug 2016
Posts: 8
Likes: 0
GL450 (2012) ; E320 Cabriolet (1995)
Today I went to the mechanic who does a great job on my '95 E320 cab, and he quoted me $3k for headbolt and valve lifter replacement, via the "traditional" method (i.e. not one bolt at a time). He has experience with this and feels comfortable doing it this way. Fine by me - I know I will feel much more comfortable taking care of the issue before I get presented with an "Add Coolant" light when I'm on a family road trip 200 miles from home.
I guess the point is that it's worth shopping it around - because the bulk of the cost comes from labor vs parts, there's a wide range of prices for doing the job.
A question I was about to ask - would the replacement be made superfluous by future upgrades to the engine? I.e should one consider spending $5k (as an example) to upgrade certain engine parts (e.g. pull out more BHP or other improvements) AND fix the factory problem versus dropping $3k just to fix the factory problem? If so, what upgrades would fix the problem and improve the engine?
I guess the point is that it's worth shopping it around - because the bulk of the cost comes from labor vs parts, there's a wide range of prices for doing the job.
A question I was about to ask - would the replacement be made superfluous by future upgrades to the engine? I.e should one consider spending $5k (as an example) to upgrade certain engine parts (e.g. pull out more BHP or other improvements) AND fix the factory problem versus dropping $3k just to fix the factory problem? If so, what upgrades would fix the problem and improve the engine?
Senior Member
Joined: Sep 2011
Posts: 302
Likes: 11
From: CA
E63 M157
Whats the name of the shop you took it to? & did they have previous experience swapping the head bolts? Looks like you're local to me
Junior Member
Joined: Feb 2016
Posts: 20
Likes: 1
From: SF Bay Area
2010 Mercedes Benz C63 AMG
Precision Motorworks
http://www.precision-motorworks.com/...ce-tuning.aspx
The owner is Chris. Great guy.
