GL450 M278 Engine Ticking / Knocking
Thread Starter
Newbie
Joined: Aug 2021
Posts: 1
Likes: 0
2013 GL 450
GL450 M278 Engine Ticking / Knocking
This is a 2013 GL450 x166 with 142,000 miles. Has had all services done regularly, plugs and coils changed last year, transmission fluid, differential fluid changed last year. A couple of years ago, the water pump was replaced. Other than the ticking/knocking noise from what appears to be the top side of the engine, the vehicle runs very smoothly without any loss in power. There is no code or CEL. The noise is mostly audible when idling and is probably drowned out at higher rpm (can't really hear anvthing around 1500 and above). I had taken it to a local MB mechanic and they had removed the oil pan below - there was no problem with rod bearings, and noise is coming from the top end near the front right (cylinder 1 or 2?). Don't know if it's a cam shaft issue, stuck lifter, cam phaser?
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
Senior Member
Joined: Oct 2018
Posts: 255
Likes: 77
From: New Jersey
GL 450
Probably right
I'm probably right, I had very similar noise 60000 miles ago and ended up replacing the engine it's been documented on here pretty well. Either drive it till it blows up or try and sell and get 10 grand
for it now.
I think you actually got more mileage out of that engine than anyone would expect. It's unfortunate but that's probably the reality when you dig through it and spend money getting a diagnosed properly.
for it now.
I think you actually got more mileage out of that engine than anyone would expect. It's unfortunate but that's probably the reality when you dig through it and spend money getting a diagnosed properly.
Member
Joined: May 2021
Posts: 154
Likes: 29
From: The Great State of Texas
GL450
Might be an exhaust leak on the manifold or at the collector, but it sounds more prevalent up top so I would guess the manifold. Take it to an exhaust shop and see if they will look at it. Can you put your hand on the motor and feel it hitting? Like something hitting the block with a hammer? If so then yeah the motor might be on it's last leg, if not then it could be a blown exhaust manifold gasket.
Chad
Chad
Out Of Control!!
Joined: Sep 2018
Posts: 14,679
Likes: 4,579
From: unbegrenzt
2017 GLE350 4MATIC
This is a 2013 GL450 x166 with 142,000 miles. Has had all services done regularly, plugs and coils changed last year, transmission fluid, differential fluid changed last year. A couple of years ago, the water pump was replaced. Other than the ticking/knocking noise from what appears to be the top side of the engine, the vehicle runs very smoothly without any loss in power. There is no code or CEL. The noise is mostly audible when idling and is probably drowned out at higher rpm (can't really hear anvthing around 1500 and above). I had taken it to a local MB mechanic and they had removed the oil pan below - there was no problem with rod bearings, and noise is coming from the top end near the front right (cylinder 1 or 2?). Don't know if it's a cam shaft issue, stuck lifter, cam phaser?
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
Member
Joined: Aug 2019
Posts: 173
Likes: 36
2014 GL550; 2010 GL450
This is a 2013 GL450 x166 with 142,000 miles. Has had all services done regularly, plugs and coils changed last year, transmission fluid, differential fluid changed last year. A couple of years ago, the water pump was replaced. Other than the ticking/knocking noise from what appears to be the top side of the engine, the vehicle runs very smoothly without any loss in power. There is no code or CEL. The noise is mostly audible when idling and is probably drowned out at higher rpm (can't really hear anvthing around 1500 and above). I had taken it to a local MB mechanic and they had removed the oil pan below - there was no problem with rod bearings, and noise is coming from the top end near the front right (cylinder 1 or 2?). Don't know if it's a cam shaft issue, stuck lifter, cam phaser?
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
Another MBWorld member had a similar noise that turned out to be a defective spark plug - imagine replacing the engine for that. Yes, the M278 is prone to cylinder scoring (which I have and plan to rebuild) but I haven't seen a clear link between the scoring and a noise like this.
@pradmohanty if you don't give up too soon and find the root cause please update the post to help the community. I'm still searching and will update as well
Super Member
Joined: Jul 2019
Posts: 733
Likes: 297
From: New Orleans
2014 GL450, 1992 W140 300SD, 1993 W140 300SE, 1987 E30 Convertible
Could be one of the hydraulic lifters or camshaft lobe wear. Use stethoscope https://www.harborfreight.com/mechan...ope-63691.html to isolate location of the noise.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
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
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Member
Joined: Aug 2019
Posts: 173
Likes: 36
2014 GL550; 2010 GL450
It doesn't quite advance the search for a root cause. Yes, the M278 is prone to cylinder scoring but I haven't seen a clear link between the scoring and a noise like this.
Junior Member
Joined: Oct 2022
Posts: 20
Likes: 3
2014 GL450
This is a 2013 GL450 x166 with 142,000 miles. Has had all services done regularly, plugs and coils changed last year, transmission fluid, differential fluid changed last year. A couple of years ago, the water pump was replaced. Other than the ticking/knocking noise from what appears to be the top side of the engine, the vehicle runs very smoothly without any loss in power. There is no code or CEL. The noise is mostly audible when idling and is probably drowned out at higher rpm (can't really hear anvthing around 1500 and above). I had taken it to a local MB mechanic and they had removed the oil pan below - there was no problem with rod bearings, and noise is coming from the top end near the front right (cylinder 1 or 2?). Don't know if it's a cam shaft issue, stuck lifter, cam phaser?
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
https://youtu.be/YKzsor-odsA
any help would be greatly appreciated! I’d like to keep driving this as much as possible.
thanks
Junior Member
Joined: Oct 2022
Posts: 20
Likes: 3
2014 GL450
thanks for replies.
UPDATE: I got 132k miles and done the borescope at 107K and there is wear on cylinder walls. Couple of weeks ago I had a cylinder 3 ignition coil internal fault and replaced 3 and 4 with beru and ordered 6 more to replace all. Long story short, replaced the number 2 coil after the post and noise was gone instantly and sounds more quiet. There was no CEL and drive issue to begin with, maybe coil.was going bad. I will.keep an eye on this and hope it stays that way.
thanks
UPDATE: I got 132k miles and done the borescope at 107K and there is wear on cylinder walls. Couple of weeks ago I had a cylinder 3 ignition coil internal fault and replaced 3 and 4 with beru and ordered 6 more to replace all. Long story short, replaced the number 2 coil after the post and noise was gone instantly and sounds more quiet. There was no CEL and drive issue to begin with, maybe coil.was going bad. I will.keep an eye on this and hope it stays that way.
thanks
Super Member
Joined: Oct 2017
Posts: 699
Likes: 149
2015 SL550, 2017 GLS 550, 2010 G550, 1995 E320 Cabriolet
Member
Joined: Oct 2022
Posts: 111
Likes: 82
From: New Zealand
There is no known solution to cylinder scoring on the stock 278/157 crank case, however here is a list of methods to potentially alleviate this condition that I've read about on this forum and on YT:
- No WOT pulls when the engine is cold. Warm up your engine by driving in the lower RPM band before entering the higher RPM band. I aim for greater than 90C/195F oil temps before getting on it.
- Consider using LM CeraTec and/or LM MoS2 to help protect the cylinder walls and other internal components. Do your own investigation, I have used CeraTec once but will not use MoS2. I don't plan to use CeraTec again.
- Use a quality 229.5 oil with regular oil changes no greater than 5k miles (or 1 year, whichever occurs first).
- Consider using a higher weight engine oil. I've shifted over to Motul 5W50 for better engine wear protection. But do your own research, 5W50 is not currently a Mercedes recommended oil for the 278/157.
- Consider disconnecting the oil pump solenoid to return the engine to normal oil pressure throughout the RPM range. Do your own research.
- Replace the intake air filters regularly and avoid high flow after market solutions, you do not want to increase the chance of foreign debris entering the combustion chamber IMHO. I replace mine yearly (approx. 10k km's).
- Do not tune the engine on stock factory components, therefore reducing the likelihood of a bent rod and the resulting cylinder scoring. In saying that, my 157 is stock and experienced a bent rod early on in its life with a previous owner.
