Compression & Leak Down Testing
#1
Member
Thread Starter
Compression & Leak Down Testing
Have by had two cylinder misfire events in recent past, I am seeking info on approximate costs for each test, plus any tips on what to ask before and after?
Is it recommended (or required) that dealer perform these tests in order to qualify for MB extended warranty claim on engine?
Is it recommended (or required) that dealer perform these tests in order to qualify for MB extended warranty claim on engine?
#2
MBWorld Fanatic!
Join Date: Apr 2019
Location: Silicon Valley
Posts: 5,955
Received 3,665 Likes
on
2,438 Posts
MY'14 W212 M276 3.5NA @60kMi
Have by had two cylinder misfire events in recent past, I am seeking info on approximate costs for each test, plus any tips on what to ask before and after?
Is it recommended (or required) that dealer perform these tests in order to qualify for MB extended warranty claim on engine?
Is it recommended (or required) that dealer perform these tests in order to qualify for MB extended warranty claim on engine?
They may start with ignition tune-up before replacing couple injectors and conclude it's a low cylinder contribution when the same faults keep returning.
#3
Member
Thread Starter
Well, being a 12/2014 engine, I only have until this December to prove it warrants the big replacement job.
It only has 57k mi on it, however I noticed in the carfax history that ignition coil(s) were replaced in 2020 and spark plug(s) this January. I have asked a friend to try to secure the VMI so I can inspect the ‘WHY’ for coil replacement(s) at such low mileage. Going into limp mode two weeks after purchase doesn’t leave me wanting to wait around and see after extended warranty expires
It only has 57k mi on it, however I noticed in the carfax history that ignition coil(s) were replaced in 2020 and spark plug(s) this January. I have asked a friend to try to secure the VMI so I can inspect the ‘WHY’ for coil replacement(s) at such low mileage. Going into limp mode two weeks after purchase doesn’t leave me wanting to wait around and see after extended warranty expires
#4
MBWorld Fanatic!
Join Date: Apr 2019
Location: Silicon Valley
Posts: 5,955
Received 3,665 Likes
on
2,438 Posts
MY'14 W212 M276 3.5NA @60kMi
Well, being a 12/2014 engine, I only have until this December to prove it warrants the big replacement job.
It only has 57k mi on it, however I noticed in the carfax history that ignition coil(s) were replaced in 2020 and spark plug(s) this January. I have asked a friend to try to secure the VMI so I can inspect the ‘WHY’ for coil replacement(s) at such low mileage. Going into limp mode two weeks after purchase doesn’t leave me wanting to wait around and see after extended warranty expires
It only has 57k mi on it, however I noticed in the carfax history that ignition coil(s) were replaced in 2020 and spark plug(s) this January. I have asked a friend to try to secure the VMI so I can inspect the ‘WHY’ for coil replacement(s) at such low mileage. Going into limp mode two weeks after purchase doesn’t leave me wanting to wait around and see after extended warranty expires
The establishment is gonna play the clock against this issue.
Pay dealer for a compression test so they don't delay your job.
Based on the results get the misfire worked on to warranty the misfire fix.
..
#5
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Jaybird, do you have XENTRY? There is a relative compression test you can do that measures the difference in rotational speed for each cylinder. If the difference between the fastest and slowest is minimal, then you likely don't have a compression problem. If the difference is significant, then I would proceed with a manual compression and leak down test. There are probably YouTube videos showing you how to do each. Are you handy mechanically? If not, take it to a shop.
That said, I would not jump to the conclusion that you have a compression problem because of misfires.
That said, I would not jump to the conclusion that you have a compression problem because of misfires.
#6
Out Of Control!!
Join Date: Jun 2004
Posts: 11,967
Received 2,132 Likes
on
1,493 Posts
2014 E63S; AMS 100 octane ecu tune; edok tcu tune; BB intakes; dyno tuned
Well, being a 12/2014 engine, I only have until this December to prove it warrants the big replacement job.
It only has 57k mi on it, however I noticed in the carfax history that ignition coil(s) were replaced in 2020 and spark plug(s) this January. I have asked a friend to try to secure the VMI so I can inspect the ‘WHY’ for coil replacement(s) at such low mileage. Going into limp mode two weeks after purchase doesn’t leave me wanting to wait around and see after extended warranty expires
It only has 57k mi on it, however I noticed in the carfax history that ignition coil(s) were replaced in 2020 and spark plug(s) this January. I have asked a friend to try to secure the VMI so I can inspect the ‘WHY’ for coil replacement(s) at such low mileage. Going into limp mode two weeks after purchase doesn’t leave me wanting to wait around and see after extended warranty expires
The following users liked this post:
Jaybird123 (Yesterday)
#7
Member
Thread Starter
Jaybird, do you have XENTRY? There is a relative compression test you can do that measures the difference in rotational speed for each cylinder. If the difference between the fastest and slowest is minimal, then you likely don't have a compression problem. If the difference is significant, then I would proceed with a manual compression and leak down test. There are probably YouTube videos showing you how to do each. Are you handy mechanically? If not, take it to a shop.
That said, I would not jump to the conclusion that you have a compression problem because of misfires.
That said, I would not jump to the conclusion that you have a compression problem because of misfires.
Trending Topics
#8
Member
Thread Starter
interesting…I certainly want to be overreacting about the issue. Yet at the same time I don’t want the window to close on coverage for such an expensive repair should it prove necessary. I hope to have this car for 5 years, preferably without frequent misfires and limp mode scares. I’ve found out tonight that only the #1 cylinder coil has been replaced previously. Also, since I replaced #5 coil and plug, I haven’t had any misfire issues.
#9
Member
Thread Starter
I’m noticing (suspiciously) that FCP is showing Backordered status on their coils, while every other site I visit (AutohausAZ, Amazon, etc) has plenty in stock. Any idea how long FCP has been backordered? Guess I’ll call today and see if they can provide an ETA for stock
#10
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I’m noticing (suspiciously) that FCP is showing Backordered status on their coils, while every other site I visit (AutohausAZ, Amazon, etc) has plenty in stock. Any idea how long FCP has been backordered? Guess I’ll call today and see if they can provide an ETA for stock
#11
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
The following users liked this post:
BenzNinja (Today)
#13
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Have you searched and watched any YouTube videos on how this is done? It’s not rocket science. I would do it myself, but that’s just me.
But if you want to pay a shop to do it, you will need to call around.
But if you want to pay a shop to do it, you will need to call around.
The following users liked this post:
Jaybird123 (Today)
#14
Member
Thread Starter
I had not but just did, thanks to you! I’m off to buy test gear now, as I already have half of the coils and plugs removed. THANK YOU!
#15
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Good luck. It's been a while since I did a physical compression test, and then it was on a traditional port injection car. On that car, I pulled the fuse to the fuel injectors so I wouldn't flood the cylinders with gas. You may want to check if you do the same with a direct injection engine.
#16
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
This guy says to disable both the fuel pump and the spark ignition by pulling fuses. (The interesting this is that when using XENTRY to perform a relative compression test, the fuel and spark are electronically disabled by the ECU.)
The following users liked this post:
Jaybird123 (Today)
#17
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Just watch for tips. I don't know if a running test is needed.
Last edited by JettaRed; Today at 06:55 PM.
#18
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
I've never done a leak down test myself, but this is interesting.
Last edited by JettaRed; Today at 07:11 PM.
#19
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,929
Received 1,801 Likes
on
1,332 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
More good info. Seems every video you learn a little more than the last video.
Here's the leak down tester used in this video: https://a.co/d/5pPvNzo
Here's the leak down tester used in this video: https://a.co/d/5pPvNzo
Last edited by JettaRed; Today at 07:24 PM.