My startup rattle is gone
09-07-2023, 01:09 AM
#1
My startup rattle is gone
A few hundred miles ago I started having a hard time hearing the startup rattle in the morning. So I really tried to make it happen for days. Drove mid day heat, shut off for an hour, left in sun, restart, and nothing anymore. Gone.
Quick backstory on work performed, I changed the cam adjusters, tensioners, and the check valves were already back there. Idle at startup was improved, but nothing eliminated the startup rattle. Bought her at 134k, I'm up to 137k, performed that work at 135k. So 2k after the work the problem goes away. Why?
I'm attributing the correction to proper maintenance, in particular thicker better oil eventually cleaning the passageway to the tensioner allowing it to do its job quickly.
This startup rattle issue didn't start off the showroom floor. Check valves and tensioners don't always correct it. Cam adjusters will perfect idol again, but have no effect on the chain slap. I bet a million mechanics would have told me my timing chains needed to be replaced. I read so many times the chains were made of soft metal that stretched. Hell I told myself that was obviously the issue, but it wasn't. And it didn't make sense that it would take the tensioner an extra 2 to 4 seconds to make up such a small amount of slack, and then everything would be fine, until the oil left again.
It's not a oil leaving the tensioner problem, it's a oil getting to the tensioner problem, and a clean engine allows that to happen. Tolerances in the m276 and m278 are very small for this problem to occur I read.
I caught the issue in mine before any cam damage, and only had an intermittent CPS code, along with the slap sound and labored startup idol due to a buggered bank 2 intake adjuster, which is due to the chain slap, and the chain slap is due to a "faulty tensioner" they'll say, when it's just oil starved.
I read a hundred stories about the startup rattle. And every 1 in 15 or so it would mysteriously go away after an oil change or a vacuum part replacement.
I'm kind of posting this as a warning to anyone worried about getting one of these higher milage engines like an m276 or m278, don't worry. You might very well get a deal like I did with a little work, and patience. Even if the cams are bad, wouldn't be that much if doing the work yourself, for what you get in return. Mercedes doesn't have a maintenance time frame for the timing chain, it's supposed to last the life of the engine in this case.
I just took a 600 mile round trip and got 25.2mpg. At 137,000 miles. That's better than what was on the sticker, new. With 5w40 Motul in it. All highway miles, but 200 of it was bumper, hilly, and crap for milage. Had her semi loaded down, plus 2 adults and a child. Many side of the road **** breaks were made, and it was 100F all day. I also don't drive slow, 100 was hit passing truck multiple times, and Cruise was set at 88 a lot. What a performance. For 12k this this luxury tank is going to last a long time.
Quick backstory on work performed, I changed the cam adjusters, tensioners, and the check valves were already back there. Idle at startup was improved, but nothing eliminated the startup rattle. Bought her at 134k, I'm up to 137k, performed that work at 135k. So 2k after the work the problem goes away. Why?
I'm attributing the correction to proper maintenance, in particular thicker better oil eventually cleaning the passageway to the tensioner allowing it to do its job quickly.
This startup rattle issue didn't start off the showroom floor. Check valves and tensioners don't always correct it. Cam adjusters will perfect idol again, but have no effect on the chain slap. I bet a million mechanics would have told me my timing chains needed to be replaced. I read so many times the chains were made of soft metal that stretched. Hell I told myself that was obviously the issue, but it wasn't. And it didn't make sense that it would take the tensioner an extra 2 to 4 seconds to make up such a small amount of slack, and then everything would be fine, until the oil left again.
It's not a oil leaving the tensioner problem, it's a oil getting to the tensioner problem, and a clean engine allows that to happen. Tolerances in the m276 and m278 are very small for this problem to occur I read.
I caught the issue in mine before any cam damage, and only had an intermittent CPS code, along with the slap sound and labored startup idol due to a buggered bank 2 intake adjuster, which is due to the chain slap, and the chain slap is due to a "faulty tensioner" they'll say, when it's just oil starved.
I read a hundred stories about the startup rattle. And every 1 in 15 or so it would mysteriously go away after an oil change or a vacuum part replacement.
I'm kind of posting this as a warning to anyone worried about getting one of these higher milage engines like an m276 or m278, don't worry. You might very well get a deal like I did with a little work, and patience. Even if the cams are bad, wouldn't be that much if doing the work yourself, for what you get in return. Mercedes doesn't have a maintenance time frame for the timing chain, it's supposed to last the life of the engine in this case.
I just took a 600 mile round trip and got 25.2mpg. At 137,000 miles. That's better than what was on the sticker, new. With 5w40 Motul in it. All highway miles, but 200 of it was bumper, hilly, and crap for milage. Had her semi loaded down, plus 2 adults and a child. Many side of the road **** breaks were made, and it was 100F all day. I also don't drive slow, 100 was hit passing truck multiple times, and Cruise was set at 88 a lot. What a performance. For 12k this this luxury tank is going to last a long time.
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calder-cay (09-07-2023)
09-07-2023, 09:03 AM
#2
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A few hundred miles ago I started having a hard time hearing the startup rattle in the morning. So I really tried to make it happen for days. Drove mid day heat, shut off for an hour, left in sun, restart, and nothing anymore. Gone.
Quick backstory on work performed, I changed the cam adjusters, tensioners, and the check valves were already back there. Idle at startup was improved, but nothing eliminated the startup rattle. Bought her at 134k, I'm up to 137k, performed that work at 135k. So 2k after the work the problem goes away. Why?
I'm attributing the correction to proper maintenance, in particular thicker better oil eventually cleaning the passageway to the tensioner allowing it to do its job quickly.
This startup rattle issue didn't start off the showroom floor. Check valves and tensioners don't always correct it. Cam adjusters will perfect idol again, but have no effect on the chain slap. I bet a million mechanics would have told me my timing chains needed to be replaced. I read so many times the chains were made of soft metal that stretched. Hell I told myself that was obviously the issue, but it wasn't. And it didn't make sense that it would take the tensioner an extra 2 to 4 seconds to make up such a small amount of slack, and then everything would be fine, until the oil left again.
It's not a oil leaving the tensioner problem, it's a oil getting to the tensioner problem, and a clean engine allows that to happen. Tolerances in the m276 and m278 are very small for this problem to occur I read.
I caught the issue in mine before any cam damage, and only had an intermittent CPS code, along with the slap sound and labored startup idol due to a buggered bank 2 intake adjuster, which is due to the chain slap, and the chain slap is due to a "faulty tensioner" they'll say, when it's just oil starved.
I read a hundred stories about the startup rattle. And every 1 in 15 or so it would mysteriously go away after an oil change or a vacuum part replacement.
I'm kind of posting this as a warning to anyone worried about getting one of these higher milage engines like an m276 or m278, don't worry. You might very well get a deal like I did with a little work, and patience. Even if the cams are bad, wouldn't be that much if doing the work yourself, for what you get in return. Mercedes doesn't have a maintenance time frame for the timing chain, it's supposed to last the life of the engine in this case.
I just took a 600 mile round trip and got 25.2mpg. At 137,000 miles. That's better than what was on the sticker, new. With 5w40 Motul in it. All highway miles, but 200 of it was bumper, hilly, and crap for milage. Had her semi loaded down, plus 2 adults and a child. Many side of the road **** breaks were made, and it was 100F all day. I also don't drive slow, 100 was hit passing truck multiple times, and Cruise was set at 88 a lot. What a performance. For 12k this this luxury tank is going to last a long time.
Quick backstory on work performed, I changed the cam adjusters, tensioners, and the check valves were already back there. Idle at startup was improved, but nothing eliminated the startup rattle. Bought her at 134k, I'm up to 137k, performed that work at 135k. So 2k after the work the problem goes away. Why?
I'm attributing the correction to proper maintenance, in particular thicker better oil eventually cleaning the passageway to the tensioner allowing it to do its job quickly.
This startup rattle issue didn't start off the showroom floor. Check valves and tensioners don't always correct it. Cam adjusters will perfect idol again, but have no effect on the chain slap. I bet a million mechanics would have told me my timing chains needed to be replaced. I read so many times the chains were made of soft metal that stretched. Hell I told myself that was obviously the issue, but it wasn't. And it didn't make sense that it would take the tensioner an extra 2 to 4 seconds to make up such a small amount of slack, and then everything would be fine, until the oil left again.
It's not a oil leaving the tensioner problem, it's a oil getting to the tensioner problem, and a clean engine allows that to happen. Tolerances in the m276 and m278 are very small for this problem to occur I read.
I caught the issue in mine before any cam damage, and only had an intermittent CPS code, along with the slap sound and labored startup idol due to a buggered bank 2 intake adjuster, which is due to the chain slap, and the chain slap is due to a "faulty tensioner" they'll say, when it's just oil starved.
I read a hundred stories about the startup rattle. And every 1 in 15 or so it would mysteriously go away after an oil change or a vacuum part replacement.
I'm kind of posting this as a warning to anyone worried about getting one of these higher milage engines like an m276 or m278, don't worry. You might very well get a deal like I did with a little work, and patience. Even if the cams are bad, wouldn't be that much if doing the work yourself, for what you get in return. Mercedes doesn't have a maintenance time frame for the timing chain, it's supposed to last the life of the engine in this case.
I just took a 600 mile round trip and got 25.2mpg. At 137,000 miles. That's better than what was on the sticker, new. With 5w40 Motul in it. All highway miles, but 200 of it was bumper, hilly, and crap for milage. Had her semi loaded down, plus 2 adults and a child. Many side of the road **** breaks were made, and it was 100F all day. I also don't drive slow, 100 was hit passing truck multiple times, and Cruise was set at 88 a lot. What a performance. For 12k this this luxury tank is going to last a long time.
Last edited by W205C43PFL; 09-07-2023 at 09:05 AM. Reason: Included link to the service TIPS doc.
09-07-2023, 09:39 AM
#3
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2014 GLK350 base model ; 2001 E320 base
So, to be clear (still a bit sleepy here), you were using Motul? And you've switched? To what oil?
(sidenote: not trying to start an "oil thread", just curious about the switch - and yes, other things were done, and the oil switch might be a coincidence)
09-07-2023, 10:30 AM
#4
MBWorld Fanatic!
Oil grade is practically irrelevant, as long as the oil is MB 229.5 approved. The actual "thickness" of the oil is measured more appropriately in HTHS rating, and all 229.5 spec oils must have at least 3.5 HTHS rating (regardless of weight).
Bottom line: feed your M276 only approved 229.5 spec oil.
Bottom line: feed your M276 only approved 229.5 spec oil.
