Best source for M276 secondary tensioners and checkvalves
Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
Best source for M276 secondary tensioners and checkvalves
Greetings. First post.
Long time BMW owner, hot rod builder and wrench turner. Just bought my first MB - 2012 ML350 with 93K on the clock. Bought for a daily driver and infrequent boat tower. Liked the fact that it didn't have air suspension and didn't have a turbo. Absolutely nothing against turbos, just not for me in a DD.
Did my homework and was well aware of the M276 cold start rattle and this vehicle did not have it on the used car lot where I bought it. I even felt the block to be sure it was cold when I started it. Vehicle started fine, ran/drove great and had very few faults. Checked for pending codes (none) and the IM registers were all full and OK. Bought it on the spot. Next morning startup - you guessed it...3 seconds of rattle and then a nice, quiet, smooth idle. Guess the guy at the lot started the car just before I got there and got some oil into the tensioners without warming the engine. Oh well. It is what it is.
I've looked over a bunch of videos and it looks like a tedious but straightforward job.
It looks like I need:
2 secondary tensioners
2 check valves (but which ones - small or large...or are there more)?
Tube of MB sealant
Intake manifold seals (6)
I'll be careful and reuse the aluminum cover bolts
So here are the questions:
1. Is there anything else I need?
2. What's the best source for these parts?
Thanks in advance for helping a newcomer. Looking forward to becoming part of this community
Mariner 1
Long time BMW owner, hot rod builder and wrench turner. Just bought my first MB - 2012 ML350 with 93K on the clock. Bought for a daily driver and infrequent boat tower. Liked the fact that it didn't have air suspension and didn't have a turbo. Absolutely nothing against turbos, just not for me in a DD.
Did my homework and was well aware of the M276 cold start rattle and this vehicle did not have it on the used car lot where I bought it. I even felt the block to be sure it was cold when I started it. Vehicle started fine, ran/drove great and had very few faults. Checked for pending codes (none) and the IM registers were all full and OK. Bought it on the spot. Next morning startup - you guessed it...3 seconds of rattle and then a nice, quiet, smooth idle. Guess the guy at the lot started the car just before I got there and got some oil into the tensioners without warming the engine. Oh well. It is what it is.
I've looked over a bunch of videos and it looks like a tedious but straightforward job.
It looks like I need:
2 secondary tensioners
2 check valves (but which ones - small or large...or are there more)?
Tube of MB sealant
Intake manifold seals (6)
I'll be careful and reuse the aluminum cover bolts
So here are the questions:
1. Is there anything else I need?
2. What's the best source for these parts?
Thanks in advance for helping a newcomer. Looking forward to becoming part of this community
Mariner 1
MBWorld Fanatic!
Joined: May 2021
Posts: 2,524
Likes: 2,041
From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Greetings. First post.
Long time BMW owner, hot rod builder and wrench turner. Just bought my first MB - 2012 ML350 with 93K on the clock. Bought for a daily driver and infrequent boat tower. Liked the fact that it didn't have air suspension and didn't have a turbo. Absolutely nothing against turbos, just not for me in a DD.
Did my homework and was well aware of the M276 cold start rattle and this vehicle did not have it on the used car lot where I bought it. I even felt the block to be sure it was cold when I started it. Vehicle started fine, ran/drove great and had very few faults. Checked for pending codes (none) and the IM registers were all full and OK. Bought it on the spot. Next morning startup - you guessed it...3 seconds of rattle and then a nice, quiet, smooth idle. Guess the guy at the lot started the car just before I got there and got some oil into the tensioners without warming the engine. Oh well. It is what it is.
I've looked over a bunch of videos and it looks like a tedious but straightforward job.
It looks like I need:
2 secondary tensioners
2 check valves (but which ones - small or large...or are there more)?
Tube of MB sealant
Intake manifold seals (6)
I'll be careful and reuse the aluminum cover bolts
So here are the questions:
1. Is there anything else I need?
2. What's the best source for these parts?
Thanks in advance for helping a newcomer. Looking forward to becoming part of this community
Mariner 1
Long time BMW owner, hot rod builder and wrench turner. Just bought my first MB - 2012 ML350 with 93K on the clock. Bought for a daily driver and infrequent boat tower. Liked the fact that it didn't have air suspension and didn't have a turbo. Absolutely nothing against turbos, just not for me in a DD.
Did my homework and was well aware of the M276 cold start rattle and this vehicle did not have it on the used car lot where I bought it. I even felt the block to be sure it was cold when I started it. Vehicle started fine, ran/drove great and had very few faults. Checked for pending codes (none) and the IM registers were all full and OK. Bought it on the spot. Next morning startup - you guessed it...3 seconds of rattle and then a nice, quiet, smooth idle. Guess the guy at the lot started the car just before I got there and got some oil into the tensioners without warming the engine. Oh well. It is what it is.
I've looked over a bunch of videos and it looks like a tedious but straightforward job.
It looks like I need:
2 secondary tensioners
2 check valves (but which ones - small or large...or are there more)?
Tube of MB sealant
Intake manifold seals (6)
I'll be careful and reuse the aluminum cover bolts
So here are the questions:
1. Is there anything else I need?
2. What's the best source for these parts?
Thanks in advance for helping a newcomer. Looking forward to becoming part of this community
Mariner 1
If I were to buy them, I would use FCP Euro, for example,
https://www.fcpeuro.com/Mercedes~Ben...atic&year=2012
I recall seeing a "chain tensioner kit" that had the two sizes for the check valves. There are two different ones,
https://www.fcpeuro.com/Mercedes~Ben...atic&year=2014
Last edited by JCM_MB; Mar 5, 2026 at 08:37 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,934
Likes: 6,778
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
.... further more
As it turn out the 2x secondary ratcheting chain tensioners already have a built-in check valve... but can still rattle with or without the external check valve. Replace them is money well spent!
While in there inspect your intake VVT's are not rattling unlocked.
Lastly install sacrificial pigtail extensions over CPS + Solenoids to prevent the usual "$10k oil in harness".
While in there inspect your intake VVT's are not rattling unlocked.
Lastly install sacrificial pigtail extensions over CPS + Solenoids to prevent the usual "$10k oil in harness".
Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
Thanks for the information and insight. I checked the door frame tag and the build date of my ML350 is 10/11. FCP Euro lists the cutoff at 1/31/12.
1. Is it correct that the build date of the vehicle can be used to determine with tensioner to use?
2. Can this build date be used to determine which check valve is used? Or should I order two of each and return the two I don't use?
3. Hadn't heard that sacrificial pigtails can reduce the chance of oil in the wiring harness. Where can I get these?
Thanks for the assistance.
Mariner1
1. Is it correct that the build date of the vehicle can be used to determine with tensioner to use?
2. Can this build date be used to determine which check valve is used? Or should I order two of each and return the two I don't use?
3. Hadn't heard that sacrificial pigtails can reduce the chance of oil in the wiring harness. Where can I get these?
Thanks for the assistance.
Mariner1
MBWorld Fanatic!
Joined: May 2021
Posts: 2,524
Likes: 2,041
From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Thanks for the information and insight. I checked the door frame tag and the build date of my ML350 is 10/11. FCP Euro lists the cutoff at 1/31/12.
1. Is it correct that the build date of the vehicle can be used to determine with tensioner to use?
2. Can this build date be used to determine which check valve is used? Or should I order two of each and return the two I don't use?
3. Hadn't heard that sacrificial pigtails can reduce the chance of oil in the wiring harness. Where can I get these?
Thanks for the assistance.
Mariner1
1. Is it correct that the build date of the vehicle can be used to determine with tensioner to use?
2. Can this build date be used to determine which check valve is used? Or should I order two of each and return the two I don't use?
3. Hadn't heard that sacrificial pigtails can reduce the chance of oil in the wiring harness. Where can I get these?
Thanks for the assistance.
Mariner1
Not certain how to determine the correct check valve w/o looking/measuring them on the head. The "kit" used to have both.
here is the "original document" explaining the check valve parts numbers and details for every engine ( https://static.nhtsa.gov/odi/tsbs/20...62561-2280.pdf) . The document has been updated at least 14 (2019) times, adding more engine numbers
and here is the last one I know of ( https://static.nhtsa.gov/odi/tsbs/20...70532-9999.pdf ) with some pictures and details.
Last edited by JCM_MB; Mar 6, 2026 at 07:16 AM.
Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
Thanks so much for the information. Looking over the MB TSB prompts a question:
Can I install the updated secondary chain tensioners on my early production date M276 that came with the early chain tensioners?
Thanks...Steve.
Can I install the updated secondary chain tensioners on my early production date M276 that came with the early chain tensioners?
Thanks...Steve.
MBWorld Fanatic!
Joined: May 2021
Posts: 2,524
Likes: 2,041
From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
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Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
Again, thanks for the information...and your patience.
Hopefully I can learn enough to become a contributing member of this forum.
Mariner1
Hopefully I can learn enough to become a contributing member of this forum.
Mariner1
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Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
Update -
Sourced the revised secondary adjusters and check valves from MBUSA. Surprisingly, the OEM parts from MBUSA were a lot cheaper from them than both OEM and aftermarket parts from FCPEuro or AutohausAZ.
Will check back in after I complete the repair.
Mariner1
Sourced the revised secondary adjusters and check valves from MBUSA. Surprisingly, the OEM parts from MBUSA were a lot cheaper from them than both OEM and aftermarket parts from FCPEuro or AutohausAZ.
Will check back in after I complete the repair.
Mariner1
Out Of Control!!
Joined: Apr 2019
Posts: 11,934
Likes: 6,778
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
elastic parts pricing
Last edited by CaliBenzDriver; Mar 7, 2026 at 10:41 PM.
Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
True enough, but neither of the retailers I usually deal with had the updated OEM tensioners at all. As a long time BMW owner (2 currently, 8 in total), My tendency is to go with OEM hard parts when the drivetrain is involved.
Mariner1
Mariner1
Out Of Control!!
Joined: Apr 2019
Posts: 11,934
Likes: 6,778
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
tension part upgrade
I'm curious... would you mind sharing the P/N of your upgraded secondary tensioners ?
Last time I dealt with M276 tensioners I was left with the conclusion no tensioner upgrade had taken place since 2014.
These need oil pressure to hold chain tension. The internal spring being two-fingers strong.
Low tension is aimed at gas savings
Last edited by CaliBenzDriver; Mar 8, 2026 at 01:02 PM.
Thread Starter
Newbie
Joined: Mar 2026
Posts: 13
Likes: 4
From: Annapolis/Ocean Pines MD
2012 ML350, 2010 Camaro 2SS, 1998 BMW M3 vert, 1985 BMW 5 Series with Procharged SBC
These tensioners may, in fact, be the ones upgraded in 2014. I checked the MB TSBs and these were the latest ones I found so I went with these.
Part numbers were 276-050-26-00-64 and 276-050-25-00-64
Mariner1
Part numbers were 276-050-26-00-64 and 276-050-25-00-64
Mariner1
Out Of Control!!
Joined: Apr 2019
Posts: 11,934
Likes: 6,778
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
BMW TO MB
Every system has it's own set of main parts with a maintenance schedule paired with a gentle failure mode.
The best way is to remain proactive with timely maintenance.
