Tom T

Hello all, I am a original owner of an 04 e320. After 4yrs, with a regular service at the dealer, the car starting to perform poorly. The most annoying thing is the rough idle and the noisy transmission. I know, this time the year, the car requires longer time to warm up. But after the engine gets to the regular running temperature, it still runs rough and noisy. The power isn't there any more. I can hear the engine or the transmission sound as I accelerate at the low RPM. This is unlike a performance of a 4 years old E-Class. I did not really pay much attention to the car lately just drive it everyday for real estate use. The car has about 42K miles. Any suggestion or idea would be greatly appreciated.
Thx.

220S

What's the dealer say about it? What about an Indie mechanic looking at it?
Hard to say based on your somewhat ambiguous description.

I once took my car (with 139,000 miles on it) to an Indie and asked for a ppi as though it wasn't my car and I was going to buy it. I got a total evaluation for $150. I ended up knowing a lot about my car's health that way

Tom T

Well, all this happens after the warranty expired (of course). I missed my last service schedule before the warranty expired by 2 days, and the service did not covered under the warranty. All I did at around 40K miles was changing oil, oil filter and air filter. I have been reading other posts, there might be a carbon deposit buildup. I just want to see if any one else experiencing the similar problem with the same mileage.

Captain FA

I just took my car in to an indie mechanic to get my serpentine belt replaced ('05 @ 56k mi). They also advised that I go buy Chevron Techron fuel system cleaner because they "heard" the carbon deposit buildup coming from the engine. I went and did it and the car runs really smooth, maybe it's just a placebo effect though . For $8 I suppose it was worth it

Tom T

I have heard the same recommendation too. It seems like this carbon deposit problem is common even with the continuous use of the premium gas. Some even recommend to inject the cleaner through the intake. Thank you for all your inputs.

philfna

So did this solve your idle problem / performance issues?

Paul04e5004M

I am in a under warranty CPOed 04 e500 with about 50K and just got my car back from the dealer after 2 weeks. I had been complaining about a ticking in the motor on cold startup that would disappear after a few minutes and this was my third visit for this problem. There were a lot of other smaller issues that I would never thought were related but did sound similar to your complaints.

I read the forums for a year about ticking until I was numb; motor mounts, incorrect oil type, defective purge valve, faulty lifters, blocked oil passages, piston slap, idler pulley....etc. No mention of carbon.

It seems that after a bore scope investigation they found an excessive amount of carbon on the tops of my pistons. They used some chemical cleaner to no avail and then proceeded to remove my cylinder heads to further investigate and do a mechanical cleaning. I was very nervous about this! What they did find was gas pooling in various places (intake and top of pistons) and discovered that I had some leaking fuel injectors. They ended up replacing all 8 and all 16 spark plugs.

There were so many drivability issues that were solved by this fix I don't know where to start (part throttle missing, rough idle, cold ticking, stumble on cold drive off, overall lack of power) all disappeared. All these problems were exaggerated by the colder weather.

Hope this assists you in some way.

mcleantmw

I've had none of these type engine operation issues with my 2003 E500.......runs smooth and well with over 61,000 miles so far.

BlueChip

My engine (2006 ML500) is presently disassembled at the dealer with the exact same problem (plus another). They did a carbon clean-up service and it did no good, as in your case. They took off the heads and found the combustion chambers on all of the cylinders coated with a hard carbon layer. It's almost as if the chamber, valves, & pistons were anodized with carbon. This, I am sure, was caused by leaking injectors, as in your case.
I have another problem, though, and that is a consistent "clicking" that is there all of the time. It doesn't go away as the car warms up. Upon inspection of the chambers, the tech noticed that in two of the cylinders the carbon has been wiped off a section of the lip while the other cylinders had a coating all the way around the rim (The rings do not wipe off all of the cylinder since they do not reach the top lip). He speculates that this is caused by the pistons in those two cylinders slapping the walls at the top.
After reading your post, I will make sure that they check the injectors for leaks and replace them if necessary. I'm still not sure what they will do to cure the slapping problem. They will contact MB on Tuesday.