Chain slap persists, startup rattle
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Chain slap persists, startup rattle
GLK 350 135k. I've replaced both tensioners, which already had check valves behind them, and I swapped all the cam adjusters. Idle at startup is much improved, what remains is a slapping chain sound. Which everything I've read says is caused by the tensioner losing its oil. And slap over time ruins the adjusters. Feel free to correct me if I'm wrong, but from many videos and articles that's what I believe to be the sequence of problems causing the startup noise.
If I'm right thus far then it seems to me like the check valves don't actually do much.
The chain doesn't feel like it has any extra slack, and the tensioners eventually do their job.
What's the solution here?
If I'm right thus far then it seems to me like the check valves don't actually do much.
The chain doesn't feel like it has any extra slack, and the tensioners eventually do their job.
What's the solution here?
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Here the "noise" even after tensioners and adjusters...
https://youtube.com/shorts/pi15y04Xcro?feature=share3
..and then it's gone and everything's fine after 2-5 seconds.
Which in my understanding is caused by the upper timing chain tensioners losing oil, while sitting. The whole MB startup rattle bulletin that effects a lot of their engines.
It was my understanding the check valve was supposed to fix this.
The adjusters I removed we're worn at the pin. There are YouTube videos dissecting the cams showing the exact damage that I found, but still that noise.
When I first bought it, 2k miles ago, the startup rattle was bad enough with the worn cam adjusters to cause the startup to sputter, blub blub blub. It's a strong start now as you can hear, no sputter for seconds like with the old bank 2 adjusted. Overall it's "better", but...
Since doing bank 1 adjusters though, no improvement. In fact I've got a CPS code now I didn't before. We'll see if that clears.. I think it's pretty clear to hear that's not an adjuster anymore if the idol is right. That sounds like chain slap to me, until the tensioner gets pressure.
The tech I called was talkative and he actually told me maybe it was the lower timing chain tensioner. I haven't looked into that yet. I might just throw some money at someone to do it. Still getting over making things a lil worse lol
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2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
That looks like an M276. Just curious about oil weight you’re using. Brand doesn’t matter. These engines really like 0W-XX weight oils. Helps get lubrication and oil pressure to the top of the engine quickly.
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I've read so many threads about this. Watched every video and read ever comment. Some get rid of it with a mystery oil, or a thicker oil, a thinner oil, a seafoam cleaning. Some folks fake the car out three times before starting it.
I'm starting to wonder if the oil starvation isn't due to build up. While it looks clean in the engine they intake valves are gunky.
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2013 glk 350
What year is it? Did you use a stethoscope (a broom stick will work) to locate exactly where the sound is coming from? On my 13 I think my high pressure fuel pump at the back of the motor makes some noise . It could be one bad lifter, or something else .
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If it was a lifter it would be continuous not just at startup right? It's gotta be oil starvation to the tensioners, and the check valves don't do much.
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If you bought it used, it's impossible to know what oils were used throughout its life and how regularly (or not) it was changed.
Many oil companies use the "meets or exceeds" language without actually obtaining the specific manufacturer approval/license. Perhaps do a few short oil change intervals with the proper MB 229.5 spec stuff and see if the noise and cleanliness improves.
Many oil companies use the "meets or exceeds" language without actually obtaining the specific manufacturer approval/license. Perhaps do a few short oil change intervals with the proper MB 229.5 spec stuff and see if the noise and cleanliness improves.
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If you bought it used, it's impossible to know what oils were used throughout its life and how regularly (or not) it was changed.
Many oil companies use the "meets or exceeds" language without actually obtaining the specific manufacturer approval/license. Perhaps do a few short oil change intervals with the proper MB 229.5 spec stuff and see if the noise and cleanliness improves.
Many oil companies use the "meets or exceeds" language without actually obtaining the specific manufacturer approval/license. Perhaps do a few short oil change intervals with the proper MB 229.5 spec stuff and see if the noise and cleanliness improves.
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2013 glk 350
No , lifter noise can be exactly that, so can high pressure fuel pump, you need to pinpoint the noise location. What if it’s at the back and not front ! My noise was from back Passenger side.
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Because it's only boarderline? I don't know. Anyone have a better explanation?
Have you checked the chain for wear?
Have you checked the chain for wear?
Last edited by John CC; Jul 25, 2023 at 02:06 PM.
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edit:
I don't even get the point of a hydraulic tensioner. Why not a spring that does the heavy lifting.
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And the fact that there were already two check valves behind my tensioners which obviously failed and didn't protect the worn camshaft adjusters, I'm thinking the same lack of protection to the new tensioners is causing the same slap minus the horrible idol ala new adjusters. 🤷
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If those check valves have even a tiny bit of gunk in them it's going to negate their existence. Release the oil pressure, and then it chain slap city.
I don't have the ***** to try to remove them. Lol, and
from what I've read other experienced, I'm not sure a second set would fit tight.
I don't have the ***** to try to remove them. Lol, and
from what I've read other experienced, I'm not sure a second set would fit tight.
Last edited by GLKwanter; Jul 25, 2023 at 08:20 PM.
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2013 glk 350
Did you ever pinpoint the sound location with a stethoscope? Sounds like valvetrain. As others have said you don’t know how it was cared for. Maybe an engine flush chemical could help. Mb oil change interval I would never follow , I think it’s just too long for especially city driving. But that’s what people do. Then ports clog as miles build up.
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Did you ever pinpoint the sound location with a stethoscope? Sounds like valvetrain. As others have said you don’t know how it was cared for. Maybe an engine flush chemical could help. Mb oil change interval I would never follow , I think it’s just too long for especially city driving. But that’s what people do. Then ports clog as miles build up.
Valve train would be continuous. Not for two to five seconds exactly like the startup rattle that's so common, and often unresolved.
I've pinpointed the issue to the hydraulic tensioners. Nothing else makes sense.
So I wonder how much pressure those hydrologic tensioners are getting at idle, and if a spring inside could do some of the heavy lifting at startup. They're the fail point for all this startup rattle timing chain slap, possibly stretch, and definitely adjuster wear, Which can even lead to cam replacement if the pressed on plates spin any.
Although I read a thread where a guy turned them back into perfect timing with a crowbar through the CPS hole and a hold on the crank.
I honestly think thinker oil makes more sense. It's better protection and the added time it takes to reach parts is going to be milliseconds, and this rattled is for 2-5 seconds.
There aren't forum posts from 2013 about this rattle, it took a few years, 60- 80,000 miles to start popping up for people. To me that says carbon build up.
I wonder about Carbon X K1 and K2. Normally I wouldn't buy into that crap because it doesn't stay long enough to really clean, but this stuff requires a neutralizer and I believe a flush of oil? Not sure. Not sold in the US.
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Hey thanks for the reply, this one drives me nuts to the point that I looked for a local indy Mb tech today.
Here the "noise" even after tensioners and adjusters...
https://youtube.com/shorts/pi15y04Xcro?feature=share3
..and then it's gone and everything's fine after 2-5 seconds.
Here the "noise" even after tensioners and adjusters...
https://youtube.com/shorts/pi15y04Xcro?feature=share3
..and then it's gone and everything's fine after 2-5 seconds.
The noise is hard to tell, almost sounds plastic on plastic. Like if you had a fan hitting shroud (I know it's not). Did you take the belt off to check all accessories? Also look at them at the start-up?
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There aren't forum posts from 2013 about this rattle, it took a few years, 60- 80,000 miles to start popping up for people. To me that says carbon build up.
I wonder about Carbon X K1 and K2. Normally I wouldn't buy into that crap because it doesn't stay long enough to really clean, but this stuff requires a neutralizer and I believe a flush of oil? Not sure. Not sold in the US.
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2013 glk 350
A valve train would not be continuous, nor would the fuel pump, it would be quiet when oil reaches the affected part.
Did you check vacume to test the PVC with a vacume gauge? To get an idea if there is an issue remove oil cap while motor is running and notice the amount of suction pulling on the oil filler cap. Lift it and put it down several times. There should be almost no pull.
It is caused by a known issue where the pvc doesn’t seal anymore to the valve cover because the gasket is bad. Excessive vacume sucks oil DOWN from the top end. PVC go bad at 70,000. Well mine went bad! You keep going to the chain, there are many more things you’re ignoring and dismissing . Havnt you replaced all the parts on the chain that could cause this ? But you continue with it.
Did you check vacume to test the PVC with a vacume gauge? To get an idea if there is an issue remove oil cap while motor is running and notice the amount of suction pulling on the oil filler cap. Lift it and put it down several times. There should be almost no pull.
It is caused by a known issue where the pvc doesn’t seal anymore to the valve cover because the gasket is bad. Excessive vacume sucks oil DOWN from the top end. PVC go bad at 70,000. Well mine went bad! You keep going to the chain, there are many more things you’re ignoring and dismissing . Havnt you replaced all the parts on the chain that could cause this ? But you continue with it.
