W166 OM642 engine cover: leave it or take it off?
Member
Joined: Dec 2010
Posts: 115
Likes: 5
97 s320
i took my upper and lower covers off for more engine bay airflow
i found grey goopy silicone looking stuff under my engine, turns out it is the motor mounts melting the silicone out (they have a liquid center) from engine bay heat
Steve
i found grey goopy silicone looking stuff under my engine, turns out it is the motor mounts melting the silicone out (they have a liquid center) from engine bay heat
Steve
MBWorld Fanatic!
Joined: Jun 2006
Posts: 1,140
Likes: 118
From: Nova Scotia, Canada
2023 GLK250, 1987 560SL
The motor mounts melting is new to me. Interesting though.
Otherwise, you won't have any real benefit from taking the covers off. Diesel engines have a lot more mass than a comparable displacement gas engine, so they seem to "feel" a lot hotter. In reality, diesels have more difficulty getting hot enough, particularly in cold weather.
In the winter, if I'm only doing short trips around town, my engine might not even get up to full operating temperature at all. The gasser gets there in a couple minutes.
Otherwise, you won't have any real benefit from taking the covers off. Diesel engines have a lot more mass than a comparable displacement gas engine, so they seem to "feel" a lot hotter. In reality, diesels have more difficulty getting hot enough, particularly in cold weather.
In the winter, if I'm only doing short trips around town, my engine might not even get up to full operating temperature at all. The gasser gets there in a couple minutes.
MBWorld Fanatic!
Joined: May 2006
Posts: 1,319
Likes: 252
From: Virginia
W212 M276 DELA 30 ; W211 M113k, W126 M117, W126 OM617, W211 OM642 ; R107 M117 X2, Sierra 1500 LZ0
I took mine off on my 211 years ago due to concerns about heat soak. so far so good, still on my original turbo and seals @ 118K
Member
Joined: Mar 2016
Posts: 87
Likes: 6
2010 GL350
Engines mounts on my GL350 were melted when I dropped the belly pans at 60k, so I removed the front belly pan to get a little more air flow. Now at 70k, removed the other belly pan because one of the new mounts is leaking. Might be simpler to move to Nova Scotia than to keep repairing this lemon...
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MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
MB engineers the covers to control airflow. See that duct in the front that puts air into the cover area?
Taking them off may make you feel better, but it takes the airflow they spent lots of time/money designing and throws it out the window. Bellypans are there for that too. All the air that comes in through the radiator is supposed to move over the powertrain and out the middle of the car. With the pans out you lose the effect.
Taking them off may make you feel better, but it takes the airflow they spent lots of time/money designing and throws it out the window. Bellypans are there for that too. All the air that comes in through the radiator is supposed to move over the powertrain and out the middle of the car. With the pans out you lose the effect.
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Thread Starter
MBWorld Fanatic!
Joined: Apr 2016
Posts: 1,124
Likes: 205
From: NW
2018 GLC 4MATIC
Wow, so different opinions in the subject.
I heard about engines mounts melted.
And after reading this blog
http://www.stephensservice.com/bluet...ssuesproblems/
I was ready to get rid of my ML, but I like it so much, and going to keep it till it dies.
)
I heard about engines mounts melted.
And after reading this blog
http://www.stephensservice.com/bluet...ssuesproblems/
I was ready to get rid of my ML, but I like it so much, and going to keep it till it dies.
)
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
Wow, so different opinions in the subject.
I heard about engines mounts melted.
And after reading this blog
http://www.stephensservice.com/bluet...ssuesproblems/
I was ready to get rid of my ML, but I like it so much, and going to keep it till it dies.)
I heard about engines mounts melted.
And after reading this blog
http://www.stephensservice.com/bluet...ssuesproblems/
I was ready to get rid of my ML, but I like it so much, and going to keep it till it dies.
)I've said that all along, the 10k service interval is just too long on these engines. They don't hold nearly enough oil for it to last that long. A normal HD truck has 12-15 quarts of oil in it, and goes for less distance between changes. They ask too much of the bluetecs, that's why they are sludged at 40k.
I actually had one the other day that had some strange issues, I took the oil filter housing out, and it was plugged solid. I had to force oil down the dipstick tube to clean it out to get a level reading, the pan is just a solid layer of sludge. The customer? Declined even doing an oil change. Car had about 18k on the oil that was in it. They only wanted what was warranty.
Member
Joined: Dec 2010
Posts: 115
Likes: 5
97 s320
MB engineers the covers to control airflow. See that duct in the front that puts air into the cover area?
Taking them off may make you feel better, but it takes the airflow they spent lots of time/money designing and throws it out the window. Bellypans are there for that too. All the air that comes in through the radiator is supposed to move over the powertrain and out the middle of the car. With the pans out you lose the effect.
Taking them off may make you feel better, but it takes the airflow they spent lots of time/money designing and throws it out the window. Bellypans are there for that too. All the air that comes in through the radiator is supposed to move over the powertrain and out the middle of the car. With the pans out you lose the effect.
you may be right, I'm just not sure.
on older vehicles there were no belly pans to speak of and now the engine compartments are all sealed up with hood pads and gaskets around the perimeter with plastic covers over everything.
i am NOT an engineer but it made sense to me to open up the bottom of the engine bay for low speed city driving when underwood temps soar
my initial thought was to trust the mercedes engineers but 10,000 mile oil changes seem insane and the heat built up under the hood when i open it seems extreme
i may examine the situation again next time its on the lift
lots of good advice on here
Steve
Thread Starter
MBWorld Fanatic!
Joined: Apr 2016
Posts: 1,124
Likes: 205
From: NW
2018 GLC 4MATIC
Hot air goes up, not sure if removing bottom cover will help a lot with air flow when car is not moving in city traffic.
Totally agreed 10K oil change intervals are crazy,
I do mine every 5K, and in summer every 3.5K.
Totally agreed 10K oil change intervals are crazy,
I do mine every 5K, and in summer every 3.5K.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
good point that i thought of also, but the airflow would be at speed like on the highway and i was thinking about city traffic when under the hood has little airflow through it,
you may be right, I'm just not sure.
on older vehicles there were no belly pans to speak of and now the engine compartments are all sealed up with hood pads and gaskets around the perimeter with plastic covers over everything.
i am NOT an engineer but it made sense to me to open up the bottom of the engine bay for low speed city driving when underwood temps soar
my initial thought was to trust the mercedes engineers but 10,000 mile oil changes seem insane and the heat built up under the hood when i open it seems extreme
i may examine the situation again next time its on the lift
lots of good advice on here
Steve
you may be right, I'm just not sure.
on older vehicles there were no belly pans to speak of and now the engine compartments are all sealed up with hood pads and gaskets around the perimeter with plastic covers over everything.
i am NOT an engineer but it made sense to me to open up the bottom of the engine bay for low speed city driving when underwood temps soar
my initial thought was to trust the mercedes engineers but 10,000 mile oil changes seem insane and the heat built up under the hood when i open it seems extreme
i may examine the situation again next time its on the lift
lots of good advice on here
Steve
Ever stand next to the car running with the a/c on? There's quite a lot of warm air that gets pushed under the car and out the sides.
I guarantee, if it was up to the engineers, they would use a better oil or more frequent changes. They are being held back by regulations, sales, etc that want less oil usage, simpler maintenance schedules, streamlined maintenance across all models, etc.
If you told a diesel customer he had to change his oil twice as often as a gas car and the oil was gonna be more expensive because it required an actual better oil, they would sell less. Can't have that.
MBWorld Fanatic!
Joined: Oct 2009
Posts: 7,010
Likes: 2,198
From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
We put 77,000 miles on our (purchased new) 2010 ML BlueTec before we traded on a similar 2014. About 8,000 of those pulling a 27' travel trailer. Original brakes.
Failures: AdBlue heater - warranty. Second gear accumulator in transmission went bad first 5,000 miles. Warranty. That's it.
Complaints - high idle (900 rpm) above 9,000 feet. NAV screen overheats above 10,000 feet and shuts down.
I suspected rear suspension bushings were getting weak, and expected to replace brakes @85-90,000 miles.
Maintenance costs compared to gas: Very similar.
Gas and diesel both have 9 qt oil capacity and the same change intervals.
AdBlue adds $22 every 10,000 miles.
Fuel filter every 20,000 miles, $200.
No spark plugs - save $500 every 50,000 miles.
In other words - maintenance is a wash.
Failures: AdBlue heater - warranty. Second gear accumulator in transmission went bad first 5,000 miles. Warranty. That's it.
Complaints - high idle (900 rpm) above 9,000 feet. NAV screen overheats above 10,000 feet and shuts down.
I suspected rear suspension bushings were getting weak, and expected to replace brakes @85-90,000 miles.
Maintenance costs compared to gas: Very similar.
Gas and diesel both have 9 qt oil capacity and the same change intervals.
AdBlue adds $22 every 10,000 miles.
Fuel filter every 20,000 miles, $200.
No spark plugs - save $500 every 50,000 miles.
In other words - maintenance is a wash.
MBWorld Fanatic!
Joined: Oct 2009
Posts: 7,010
Likes: 2,198
From: Colorado
'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
We put 77,000 miles on our (purchased new) 2010 ML BlueTec before we traded on a similar 2014. About 8,000 of those pulling a 27' travel trailer. Original brakes.
Failures: AdBlue heater - warranty. Second gear accumulator in transmission went bad first 5,000 miles. Warranty. That's it.
Complaints - high idle (900 rpm) above 9,000 feet. NAV screen overheats above 10,000 feet and shuts down.
I suspected rear suspension bushings were getting weak, and expected to replace brakes @85-90,000 miles.
Maintenance costs compared to gas: Very similar.
Gas and diesel both have 9 qt oil capacity and the same change intervals.
AdBlue adds $22 every 10,000 miles.
Fuel filter every 20,000 miles, $200.
No spark plugs - save $500 every 50,000 miles.
In other words - maintenance is a wash.
Failures: AdBlue heater - warranty. Second gear accumulator in transmission went bad first 5,000 miles. Warranty. That's it.
Complaints - high idle (900 rpm) above 9,000 feet. NAV screen overheats above 10,000 feet and shuts down.
I suspected rear suspension bushings were getting weak, and expected to replace brakes @85-90,000 miles.
Maintenance costs compared to gas: Very similar.
Gas and diesel both have 9 qt oil capacity and the same change intervals.
AdBlue adds $22 every 10,000 miles.
Fuel filter every 20,000 miles, $200.
No spark plugs - save $500 every 50,000 miles.
In other words - maintenance is a wash.
