Charlie Horse

Hi,
New to this forum and to my first MB. Was a VW driver for 30 years...so some things are a little different. Still learning Anyhow, This is a 2008 E350 with 76,000 miles. I'm getting 19mpg in the city and 26 on the highway. The engine and trans run very strong, except at idle, where there is a slight shake....almost like a lean misfire It's especially noticeable when coming to a stop or crawling (forward or reverse). No check engine light, checked for codes with a Autozone scanner and nothing to be found. Ran 2 tanks full with Seafoam added to clean out injectors. Still no change. Was thinking to change the spark plugs (cheap and easy fix) on Tuesday. Problem is more noticeable after warmed up. MB service advisor suggested motor/trans mounts (sight unseen). Idle also seems very low to me (under 600 rpm) once warmed up. Any suggestions would be appreciated.

Justinp82

I have a similar issue with my E350W4 (also a 2008 with 53,000~ miles)

Car runs fine otherwise, just sometimes sitting idle, doesn't matter if its in gear or out of gear it will just have a little shake. RPM's don't seem to drop any while its happening. You can definitely hear the "misfire" standing behind the car and listening to the exhaust.

No codes, been through many tanks of gas and its been happening for awhile. I think it happens more when there is more moisture in the air, not necessarily after a rain, perhaps moisture on a sensor or coil pack?

Not too worried about it until it starts throwing a CEL, since it's driving fine otherwise. Mentioned it to the dealer and they are beyond useless as usual.

jcat

my 500 has an intermittent almost skip feel once in a while when sitting, I don't think it's anything to be terribly worried about until it starts throwing codes or running wrong. Cars with variable cam/valve timing like ours typically idle in that 600-750rpm range.

djrabbi

mine was motor mounts.

Charlie Horse

Yea, this is a bit of a strange problem. I've searched around the forum and the best that I can deduce is possible a very small vacuum leak like a slightly cracked hose or something or maybe a bad spark plug wire (high resistance)....I'm putting plugs in tomorrow and inspecting everything. Let's see what happens.

vettdvr

Motor mounts X 2

djmallya

Replace motor mounts, but also check transmission mount. You might need all three, its cheaper to get them done at once.

BDHPlayer

Both of my Mercedes diesels have had the motor mounts replaces. One the 2005 E320 CDI at 68000 miles and the other a 2007 E320 Bluetec at 162000 miles

DubVBenz

Care to rundown the other maintenance required on your bluetec at different mileage intervals? I'm at 61K and would be interested to know.

BDHPlayer

The 2007 was purchased used at around 45000 miles. I had to replace the dricve belt when I had the engine mounts replaced. Only other maintenance on it was an oil change.

The 2005 has around 168000 miles on it. The engine mounts went at 162k. Water pump and serpentine belt went at 122k. Looks like everything else was normal wear and tear. I only started keeping records on the 2005 at 82k miles.

Charlie Horse

Okay, so I changed the spark plugs, and ofcourse no change. The plugs were a little worn but not bad. I notice if I come to a quick stop, then accelerate, I feel the driveline clunck. My suspicion is a bad trans mount, but I will have all three mounts replaced. I did (thank god) purchace an extended warranty (AUL). I wondering whether to bring to Mercedes here in PS or an independant. I'm not too sure about the independants around here...

Charlie Horse

Update. New code P0302 Cylinder 2 misfire but no CEL. Which is cylinder 2? I'll swap coil to see if it follows...
TIA

Charlie Horse

Okay, I finally broke down and to my baby to an indy today. He swapped coils, swapped spark plugs and the problem stays with cyl 2. I left here there as tech wants to swap injectors and see what happens next. I'm hopeful it's an injector, otherwise it will be compression/leak-down tests.

Justinp82

Interesting.

Thanks for the updates Charlie.

jcat

as a hunch, have you looked into the cam position sensor? I know the 350 engines had some valvetrain issues, it's cheap ane easy enough, maybe worth a shot.

Charlie Horse

PITA...the local dealer is useless. I brought the car in to finally find the cause of the shake while creeping. Keep in mind that I have an extended warranty. After three hours of diagnosis, they weren't sure what was wrong as there are no codes. Soooo, they called the warranty company and actually told them that they want to "try" motor mounts first and if that doesn't work, then replace torque converter, valve body and some kind of solenoid. The warranty company of course refused (and I don't blame them). These guys just want to throw parts at the car and see what works. That's not a mechanic, that is a parts changer... Of course the mounts fixed nothing.
I tried to show the tech that the shake is there at idle in park too, but he couldn't feel it. The problem is that the intensity of the shake is intermittent, but always there. I still think it's in the engine somewhere. The previous independent tech played musical coils (swapped around), musical spark plugs and injectors. The severity lessened after the injector swap but didn't cure. Still no codes. My guess is a cracked or defective injector as this can occur if the injector spits instead of misting. As long as there is the correct amount of fuel, no codes will show.

Sorry a little long winded. I'm just frustrated that such a simple problem can't be solved easily...HELP I need to find a REAL Mercedes tech.

LVGBENZ1356

Hey did you ever fix the problem shake with your e350? I have a similar problem with my e320 ? i have replaced coils plugs and wires plus maf sensor. while all that helped a little. my car still has that annoying shake

ozusa

If the car develops power and basically seems to run OK, except for vibration or clunking, consider your motor and / or transmission mounts. If they haven't been replaced by now, it is quite probable that one or more have failed.

Search this Forum and look on youtube for video of W211 motor mount checking. You will need the help of one other person (with a brain, but they don't need to be a mechanic by any means).

Another possibility, if the problem occurs while moving (and not when stationary) at low speeds, you may have a low fluid level in your transmission. That can cause shuddering at 5 - 10 mph.

LVGBENZ1356

i replaced all motor mounts not too long ago with beck arnley motor mounts and corteco transmission mount. the thing is i first started feeling the shake after the work was done. is it possible that the motor mounts werent put on right or the motor mounts are so cheap it caused vibration right away. i heard later that beck arnley is a cheap brand i shouldve used boge sachs.

Avatar2014

It is possible that they were not put on right. Also possible the exact matching parts were not sent to you in the first place.

Avatar2014

Charlie Rose, you never updated about your resolution to your issue. Please let us know. Thanks.

dcsimmons

I just recently ran across a similar issue, and so hopefully what I have come across will be helpful to you or others having the same issue.

If it is a very distinctive shake, like one cylinder is missing, consistently and not intermittently, than I am 98% sure it is camshaft sensor or solenoid related. If the sensor is not working correctly, it will send send faulty information to the computer, and then the computer will move the solenoid (that changes the position of the camshaft), wrongly, or not at all.

It is rare in my opinion (whatever that is worth) a sensor is the culprit in this way because the sensor just electromagnetically picks up the camshaft rotating past it and communicates when this happens to the computer. The computer compares the camshaft sensors report to the position of the crankshaft sensor and other things, and determines if it makes sense.

If its report makes no sense, then it generates a code possibly suggesting a faulty camshaft sensor. But in reality, if it reported the position to be wrong, it is more likely the camshaft solenoid isn't working correctly, and so the camshaft is retarded or advanced when it shouldn't be. The sensor picks this up as it is supposed to, and reports it to the computer. My opinion is if the sensor is bad, it wont' send a signal at all. It is just a coil of wires sensing a pulse form the camshaft rotating by. That is it! So if it fails, it should be an on or off issue, not a delayed issue.

If the solenoid is sticking, then the camshaft doesn't move as it should. A tremendous amount of the power these motors get out of the same size block as the old ones comes from moving the timing (advancing intake and retarding exhaust) of valves opening and closing. In addition, having the extremely smooth idle as well comes from retarding intake and advancing exhaust.

In the olden days, it could be argued that "oil was oil". We had different weights...some had detergents (4 stroke oil), and some didn't (2 cycle oil). but it was for the most part different viscosities otherwise. While using the wrong weight oil in your car, or changing manufacturers made a difference, it rarely was catastrophic or even much of a problem. You could just change it back again to what you had in it before and all was mostly good. If the oil got dirty, it usually meant faster wear and tear, but that was it. One of the exceptions to that was putting 4 stroke (detergent) oil in a 2-cycle engine. I learned that the hard way at the age of 10, which didn't make my father very happy. You don't just switch back to 2 stroke oil. But the engine at least is not toast!

I can't tell you how many tractors and pickups I pulled out of the grave yard on the farm (needed for an emergency). When your irrigation motor goes bad, and it will be two weeks before a new one shows up, you can't assume the corn, Milo or wheat will wait for you to get a new one. You pull your John Deere 2 cylinder (yes that is 2 cylinder) tractor out of the grave yard and run the well off a pulley till the new one shows up. And they always ran except for smoking severely.

While it was an arduous task (one of the rare times a front crank on an engine could still came in handy) to get them to start...they would always start and at least and run. And the oil that was sitting in them was more often than not sludge and black. You could barely call it oil. You can't get away with it these days with the new motors, especially if they have variable valve timing. They may not even start or run if there is a problem.

Now days if you use the wrong oil, don't change your filter in time, you are eventually screwed; and not in the good way! There are so many varieties of oil now, especially with synthetics and additives added into the mix. The harm done is primarily because of these solenoids that move the camshafts for timing purposes. They not only require "clean", extremely well "filtered" oil to keep from getting stuck, but also the right co-efficient of friction (viscosity) to slide in and out correctly. Too thick of oil will cause them to move too slowly and even stick intermittently, and too thin of oil causes them to wear quicker or move too fast. This is especially noticeable in a transmission in how it shifts. Changing the transmission fluid (not recommended to do so) can significantly change how it shifts. So it is a balancing act.

Transmissions since the late 90's / early 2000's have "valve bodies' that have a bunch of solenoids that open and close "valves" creating the "smooth" shifting we now experience in more expensive cars. Interestingly enough, the new state of the art DCT (Dual Clutch transmissions) could be argued not to only offer better performance (there is now statistically nothing faster on the road), but also in reliability. With no torque converter or valve body needed anymore, the most vulnerable component becomes the two clutches. But they are bathed in oil and so can last a long time. Several manufactures have them now. I know Porsche does (Porsche 918 Spyder, Porsche 911, Porsche Cayenne, etc with PDK. Who knows, just like when electric windows, Air conditioning, automatic transmissions, and especially the air bag (for safety) came out, the math for purchasing a newer late model car can make sense. Yes, you might be dealing with depreciation of a new car, but if you plan to keep the car for a long time. It may actually save you money in the end. There are still two solenoids for the two clutches, but that is basically it.

With today's transmissions using valve bodies/solenoids, these solenoids aren't completely "open" or "closed", but can be partially open or closed over time creating the smooth shifting results we feel. For this to work, everything has to work perfectly. The computer has to send the right amount of voltage to the solenoid for it to be open and closed the right amount, and at the right time. A "software" or "firmware" upgrade basically updates the voltages and timing of the signals/voltage to these solenoids. And when the computer "learns" how you drive to format it for your likes, it is doing nothing more than paying attention to how fast you accelerate, stomp on it, etc. If it sees you drive aggressively, it makes the solenoids open and close quickly. If it sees you are always "joy riding", it opens and closes the valves slowly, providing for very smooth and seamless shifting. It also varies the RPM at which it shifts into the other gears.

If the transmission oil gets dirty and the solenoids get stuck, you are stuck in the gear it was in, or the transmission is put into "limp mode" by the computer so you can get it to the service shop. That is if you are lucky. If they really go bad, the car doesn't move and you are even more "stuck".

If the solenoid that runs the camshaft timing goes bad, the engine often has to be completely torn down to repair them along with the camshaft balancer. If you are lucky with a transmission, you can just replace the solenoid of the valve body that has gone bad (each gear has one), but the problem is if one has gone bad, the others will as well most likely in a short amount of time and so you just fork over the dollars to replace the whole valve body.

Changing the oil much more often than the manufacturers recommend, using an extremely high grade filter, and using the exact same oil all the time the manufacturer recommends for the car is the best insurance you will have for "less" problems. I say "less", because unlike a car of the before the 70's, 80's, and even early 90's that don't have valve bodies or variable valve timing, these solenoids will go bad eventually. It is by design sometime there will be a problem because just like the cylinder sleeves wear down even with a properly maintained vehicle, the sleeves that a solenoid slide in and out of have the same issue. With cylinder sleeves, you just end up with "blow by", and at some point the compression will be so low that it won't even start. But the pistons are moved up and down mechanically, not electromagnetically and unless you throw a rod or spin a bearing, the engine will still turn over. I had a 1977 MBZ 300D with 500,000 miles on it, all original, and that is exactly what happened with it. The compression got low enough that it just wouldn't start. As you know, good compression is the key for a diesel to start.

But with a solenoid, the valve is not moved mechanically as was the case for the piston, it is moved electromagnetically. There are so many variables in involved in it working properly. The power of the electromagnets that moves it. The quality of a solenoid...what metal it is made out of, the design, etc make a huge difference. A more powerful electromagnet has a better chance of working against resistance to the solenoid. I could go on and on with this, but I'll stop here. Again, they will go bad, and correct and clean oil is key to extending their life.

It really surprises me manufacturers don't brunt some responsibility in suggesting oil changes every 10,000 miles, making owners very vulnerable. Yes, the engine makes it through the warranty, but then what!. Changing the oil ever 3,000 - 5,000 miles would probably extend things significantly. This is just my personal opinion.

Again, a tremendous amount of the power motors today get out of the same size block as the old ones comes from moving the timing (advancing intake and retarding exhaust) of valves opening and closing. With the theory being it takes time for air to move, as the engine has a higher RPM, advancing the intake timing lets the air start moving earlier so it is there when it really needs it. Retarding the exhaust is exactly the opposite.

Depending on how old you are, you may or may not remember the souped up engines with high-rise Edelbrock manifolds and tuned exhaust systems (header pipes) that were rough and noisy in the 60's and 70's. They had a really rough idle because of their horse power. Each stroke was so powerful to generate the horse power you felt it very "distinctively" when the engine was running. At the time, the only way to smooth it out would have been to put a very large flywheel taking advantage of its angular momentum. But to get them to be as smooth as they are today, the flywheel would have been so huge it would have made no sense.

One of the ways manufacturers get the new high performance engines to idle so smooth is to retard the intake valve opening and closing and advance the exhaust valve opening and closing at idle, or when the car isn't accelerating. You will feel the distinctive kick upon accelerating, but not at idle or maintaining the same speed. It is because of the same reason. Since these engines (the E-350) have dual overhead cams, the intake and exhaust valves can be advanced or retarded independently. Single overhead cams can't. And when you advance or retard the intake or exhaust valve OPENING, you also advance or retard its "CLOSING" since you aren't changing the size of the lobe on the camshaft, just changing when it starts and stops.

So if your experience is the same as mine, what you are actually feeling is the valve opening and closing as if it wants maximum power at idle since the sensor is not working correctly (unlikely) or the solenoid is stuck. My 2006 E-350 did the same thing, but the engine light did finally come on and said it had a "retarding" camshaft exhaust sensor which suggests it is trying to assist in generating power at idle.

I hope this helps!