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TylerH860 03-15-2015 11:58 PM

2005-2006 E320 CDI Buyers Guide, Common Problems, & Roll Call
Time for a dedicated thread given all the recent purchases and bring some Google traffic our way. This thread will be continuously edited so feel free to contribute and I will add to the post. Also, let's have a CDI owners roll call. List your current miles along with non-maintenance related repairs. Date of purchase and price (optional) as well. This will help greatly with the buyers guide.

For the perspective buyer and the CDI unwashed, hurry up and buy one. You will not find a more satisfying car. It's the best diesel passenger car you can buy right now for under 20k. You won't be associated with the jerks that own BMWs should you purchase a 335d. With Volkswagen you have to worry about engines, transmissions, injector pumps, rattles, interior bits breaking off in your hands... basically everything. The CDI feels like it has enough torque to stop the rotation of the earth should you romp on it. It also rolls some serious coal, a very satisfying belch of soot out the back while you're hitting that 6 second 0-60. At normal highway speeds, over 40MPG is widely reported along with 700 mile range on a single tank. If you're old school, you'll like that it has an iron block inline 6 engine, and the old 722.6 transmission known for the same durability as Thor's hammer. If you're up with the times, it has all the tech you would ever want. It's also a pretty car. The design is not polarizing or ostentatious. Just a stately car that blends with whatever level of society you consider yourself.

It seems something is in the water recently and people are dumping these CDIs for peanuts. Nice cars with under 200k and good service history are popping up everywhere... The realistic price range seems to be $7000-$17000 depending on mileage. Just a few years ago, prices were nearly double. It's safe to say they have bottomed out. Considering old W123s in similar condition and mileage can bring the same money, and you're dealing with maintaining a 30+ year old slow vehicle that gets 25 MPG downhill, the CDI just makes sense. With so many available, you can be picky. No reason to buy third or fourth hand from cousin Vinny off south Broadway. Just like with 80's W123 300Ds when you were shopping for them 10 years ago, there's owners that fixed things in a timely manner and decided to get something new, and there's owners who let issues pile up and play pass the turd when it becomes too much.

Unlike when you were shopping for a W123, every dealer repair should be stored in the computer. All original warranty work is accessible to all Mercedes dealers. Anything after that is kept with the dealer that performed the work, and reported on the vehicle history report. For the most part, the days are gone of phone book thick paper maintenance records or run away. A little time at the dealer or $30 for a history report can tell you alot.

Speaking of dealers, the car business has completely changed. New car dealers are hanging on to every used car trade-in possible. The only cars second hand dealers can get their hands on are the reject trade ins. These dealers usually do not have the resources or the interest to recondition these cars to the level of the keepers at the new car dealers. As a former used car slimer myself it's hard for me to say, but avoid used car dealers. You will see higher asking prices with new car dealers, but big haggling is their style.

I purchased my CDI from Plaza Mercedes outside of St. Louis. It was a 1 owner new car trade in serviced nowhere but their dealership. With just under 200k, a few years ago it would have immediately tossed to the auction only because of the high mileage. I would guess they gave him around $6500 in trade, and spent $500 in detailing, services, and a few minor repairs. It was on their lot for $9995. I offered $8000 out the door and they accepted quickly without much dance. It was a full red carpet transaction just like the other guy spending $100k on new S class was getting. They even offered me their undercoating and paint finish protection with door ding insurance for an additional $7000. Absolutely true story. Sure there's exceptions to everything and plenty of private party sellers with good cars, but you'll find the most good cars at new car dealers. Just ignore their silly asking prices.

Unlike W123 ownership, these cars can't be fixed with just a few bents wrenches, a hammer, and manly forearms. Other than basic diagnostics and repairs, you will need some form of way to interact with the car's computer. Whether you buy a used or Chinese copy of Mercedes Star SDS system, or some other advanced diagnostic computer with the right software to interact, if you plan on doing much DIY you will need these. While they cost at least a grand unless you find some bargain, it makes diagnostics much easier. Gone are the days of guessing. These cars will know exactly what's wrong with them and the right computer will tell you step by step how to fix them. Every fault is stored; I wouldn't be surprised if the car remembers the last time you farted in the seats. This does get annoying, as many things require the computer to reset the fault or reprogram the part. For example, if you were to evacuate and recharge your AC system, you have to reset the computer in order for your AC to work. It does not want to switch on with any active fault. If you don't want to work on it yourself, I would say the running costs would be about the same as maintaining a 30+ year old Mercedes. Figure spending a few grand a year in upkeep. Some years better, some worse.

There's lots of conjecture on proper service intervals. Mercedes intervals it at 13,000 miles and that's probably fine with how advanced synthetic oil is now. You could do half those intervals, it certainly wouldn't hurt. Sludge does not seem to be a problem in this engine compared to other Mercedes gasoline engines. Transmissions are "sealed for life" and that should certainly be ignored. I wouldn't want more than 100k on transmission fluid. Same goes for other fluids. Even good cars serviced regularly with good sellers will have hidden problems, so its worth knowing the common problems these cars have. Most non MB dealers wouldn't pull the engine cover to look for black death around the injectors, and could easily miss worn ball joints or one of hundreds of electronic doohickeys that can break. So its good to know the common problems which is listed below.

Black Death (injector seal leakage): Sounds a lot worse than it is, but is something to keep an eye on. Underneath the useless decorative engine cover can hide a nasty surprise. During your first inspection under the hood, warnings signs for this would be a burning oil smell or an extra hissing tick noise outside the normal diesel clatter. You will still want to take the engine cover off and examine the injectors. Next time my engine cover is off I think I'll write an inspirational message in silver Sharpie. Like "Once more unto the breach".

On higher mileage cars its almost certain you will find a hint of it around the injectors. No big deal. You can use this as a factor in your negotiations as this is something that will need to be monitored and eventually addressed. Wait too long this build up can ruin your injectors and wiring. Also, I am told the longer you let it build up, the harder it is to remove the injectors and good metal surface to reseal properly. Quality injectors will set you back $450-$600 each. Seals not very much. Some have reported VW injector seals are superior to the Mercedes supplied ones.

Video of an extreme case of "Black Death"... or when you eat too much Taco Bell

Transmission Conductor Plate: A common problem is your transmission to get "stuck" in fourth gear after a highway run, requiring you to shut the vehicle off. This electronic unit inside the transmission can cause plenty of issues. $1000 fix at the dealer. You will need the SDS tool to reset the transmission control module otherwise the fault will remain.

Battery Messages: The W211 chassis has 2 batteries. The redundancy is due to the electronic brake (SBC) system. There is one large battery in the trunk and another small motorcycle sized under the hood, below the cabin air filter. A black message reading "low battery, conventional functions unavailable" light usually point to the main (rear) battery. A red message saying "low battery visit workshop" points towards the small auxiliary battery in the front. Early in the W211 production, there were issues with alternators and battery control modules causing errant warnings and other issues, but these seem rare by 2005.

SBC braking system (Brake Messages): I think of Jeremy Clarkson's car reviews when he gushes on about the fantastic machine he's driving, then starts to notice the annoyances. If this car has a BUT, its this system. Mercedes abandoned SBC brakes starting in 2007 and is the likely cause of their reliability ratings going down the toilet during those years. Given Mercedes successfully pioneered throttle by wire systems which gave us the annoying nanny of traction control, along with inventing ABS brakes, you can understand their zeal running amok when they created this brake by wire system. Lot's of little idiosyncrasies. Like if you're doing your own brake pads and your wife decides to open the vehicle's door to grab her purse, the brakes engage and chop your fingers off.

Service records are very important with the SBC system as it tells you if the SBC pump has been replaced and if all the campaigns have been done. If you get a "service brake, visit workshop" message, the code will usually read that your SBC pump is worn out, but wait! After replacing tons of good pumps because the software said they were worn out, their final fix was to reprogram the "replace the pump" timer to an unspecified time well beyond their warranty. (So nice of them). Many cars never got this "reprogramming" and will surprise you with this message. There's lots of conjecture about the reliability of this system since, but if there's no records of the pump being replaced I would keep that in the back of my mind, as its a spendy repair ($2000). They extended the warranty on the SBC system to 10 years and unlimited miles, expired on alot of CDIs by now.

Lower Ball Joints: If you hear a creaking noise over bumps or notice uneven tire wear, chances are its the lower ball joints. If you're looking at a car with over 100k on the originals, it's almost certain this needs to be done. This is not a pricey repair.

Electrical: This is already turning into a book and I don't want to turn it into an encyclopedia talking about all little electronic things that break, but know there's alot of them. It's usually rare and random when they break. Some highlights include the car thinking someone is sitting in the passenger seat and will annoyingly chime for your phantom passenger to buckle up. This requires a SDS tool reprogramming of the seat with a weighted Mercedes butt simulator tool. They literally have something that simulates a butt in the seat to perform this task. If the car you are looking at has keyless go, (unlocks and starts car by proximity sensor in your key which never leaves your pocket) do not plan on it working. Also another amusing throwback repair is the electric monovalve for the climate control system. 40 years later they still design a monovalve that gets stuck on hot or cold, like they are paying tribute to issues past. Like I said, these issues are usually rare and easy enough to fix, unless it's keyless go. Maybe label the start/stop button on the shiftier knob "eject passenger" for gags?
Ejecto Seato Cuz!

Like I said, any additions welcome, and please star the roll call. I will with the next post.

TylerH860 03-16-2015 12:07 AM

2005 E320CDI 199,000 miles purchased March 2015 for $8000. 1 owner car with Designo Expresso package, HK stereo, xenon lights, panoramic roof, keyless go, navigation, and heated seats. It came with a full service history from day 1. Repairs include:

Never towed in. Other than normal maintenance, some fuel leaks, quite a few suspension parts replaced, and tons of repair attempts on the troublesome keyless go system, the only surprise repair was an EGR & Turbo replacement at 60k. This stemmed from a sluggish engine problem that the techs had a difficult time diagnosing. Thankfully the original owner purchased an extended warranty covering the car to 100k. Nice to see records of injector seals, lower ball joints, glow plugs, transmission service at 100k, and battery control module replacement. Other than the normal service campaigns, nothing has been done to the SBC system.

I have bought and sold 4 other 2005-2006 CDIs in the past and several other W211s. I used to own a used car lot specializing in old Mercedes and got to know them pretty well.

Skid Row Joe 03-16-2015 01:01 AM

3 Attachment(s)
2006 E320 CDI 59K bought 6/'13 from it's original sold new MB dealer. Car in almost perfect appearance condition, and of course perfect mechanical condition. Bought 20%+ off dealer asking. Tons of work done on it with complete records, both Carfax and VMI. Complete sorting & prepping to sell work as needed done before putting it out on the MB dealer's lot.

I would never buy a used MB of this caliber from a used car lot. Too risky in terms of more money needed to be spent on them immediately - as many CDI buyers here are finding out.

TylerH860 03-16-2015 01:03 AM


Originally Posted by Skid Row Joe (Post 3453537)
2006 E320 CDI 59K bought 5/'13 from it's original sold new MB dealer. Car in almost perfect appearance condition. Bought less than 20% of asking. Tons of work done on it with complete records, both Carfax and VMI. Complete prepping and work as needed done before putting it out on the lot.

Any repairs outside of maintenance since purchase? Lower Ball Joints, injector seals, SBC system all untouched?

Skid Row Joe 03-16-2015 01:19 AM


Originally Posted by TylerH860 (Post 3453538)
Any repairs outside of maintenance since purchase? Lower Ball Joints, injector seals, SBC system all untouched?

All the above untouched, as per records and my usage started 6/'13.
One GP failed before I bought the car as per records.
Ribbed V-Belt changed as per records.
Numerous brake pads and rotors changed before buying - this is normal. These cars eat both pads and rotors X 2 what my other MBs have.

Under my 6K driving since buying:
Plenum gasket needed R & Red - it was leaking oil.

Elected to install (6) new glow plugs.

Fuel tank door locking pin device needed R & Red.

Blower motor replaced. Original was ticking at low RPM, and bothersome.

I changed out both engine mounts myself - one was leaking - spewing brownish hydraulic liquid. The pair of engine mounts were just over $300.00 - even @ MBCA Member pricing.

Have had fuel filter/ oil/oil filter replaced.

If anyone is buying one of these thinking they'll never need to spend time and money (at times a lot of both!) keeping them up-to-snuff, I think they're going to be very disappointed.

chronometers 03-16-2015 01:30 AM

I got my 2005 E320 CDI in October from an MB Dealer near my home. Cost was just shy of $15k.

It has 90k miles and has Pewter (Cubanite) exterior with charcoal nappa leather interior.

Options that I wanted were Dynamic seats, Active Bi-Xenon, and folding split back seats. It also had power closing trunk, HK stereo, cd changer, DVD Nav., rear sun shades in side windows and powered shade on rear window.

Vehicle has good service history at Mercedes Dealers except last two service visits which were at indies.

Car drives really well. I am still keeping my '95 E300 as this is a tank. The E320 is more refined but I am uncertain about giving it a "tank" designation yet.

One item missed and I did subsequently was a brake fluid flush.

Transmission had a plug changed under warranty (common issue apparently) and ATF was changed at that time. This was 60k miles and 7-8 years ago. I will do aff change when I do next oil change.

Other common maintenance issues that cropped up on this example from the VMI were:

glow plugs, glow plug controller, battery controller and thermostat. TPM (air pressure monitors) on wheels went out also. These were all fixed by previous owner in and out of warranty.

shertex 03-16-2015 09:30 AM

At the risk of being a bit of an interloper (I don't own a CDI yet), I am interested in people's thoughts as to how to balance the mileage/price issue. Assuming well-documented maintenance in all cases, where is one likely to get the most bang for the buck? And at what mileage does one begin to incur significant risk in terms of maintenance costs going forward?

I suspect I'd be willing to spend a bit more to get something in, say, the 150k mile range. But I wouldn't be averse to buying one with 250k miles for the right price.

There is a well-maintained one where I made some inquiries with 260k miles asking $8000. Sounds fair but not a GREAT deal.

chronometers 03-16-2015 12:30 PM

Hmmm....Here was my rough way of thinking about it.

I came up with a approximate value for a well maintained example with say 100k miles using KBB and NADA. I also monitored sites to get an idea what they were actually trading for.

I was then using a quick back of envelope calculation of adding/subtracting $1k for each 10k miles a vehicle had above or below 100k miles. Perhaps 100k is a sweet spot. Banks don't like to make loans on cars above that level and it is a psychological point where many people would not consider purchasing a car. That said, I would not hesitate to buy one of these vehicles with 200, 300 or perhaps even 400k given it is priced accordingly. There have a been several high mileage ones that have sold and it indicates that they have mileage longevity in their genes.

For my search, I also added or subtracted some for maintenance. If a vehicle had the SBS pump replaced, I might add X or if tires were 50%, I might subtract Y. You might be able to eliminate a vehicle from consideration if maintenace history is missing. I strongly recommend doing this or at least subtracting a lot. These cars do not seem to tolerate missed maintenance.

I also added a value for options. When buying a used car, options are not valued to heavily but.....I wanted a car with specific options and was willing to pay a bit more for one.

Add some for Southern or West Coast car. Don't necessarily eliminate a Norther car though. Mine was owned by a surgeon and not driven very much in winter as he had a SUV for snow.

Add some for MB Dealer....yes you will pay more when buying from a dealer....but in long run, you get benefit of a vehicle that should have been checked out and maintenance can be easily verified. When negotiating, go through the maintenance history and make sure everything has been done or will be done. Had I followed this carefully, I might have been able to get a brake flush thrown in. An MB Dealer will have the Service department go over the vehicle, as the sales person or service manager what the service department recommended. All this being said, you may actually get a good price from a dealer......some MB dealers don't specialize or sell many diesel vehicles. They want to turn inventory.

Lastly, pay yourself....convenience and your time should be factored in. If it is easy for you to go see a car, that is worth something.

To start, go to the MB web site: There are always 6-12 vehicles nationwide at various dealers. They turn over fairly quickly so if one catches your eye, call and talk to someone.

GregMN 03-16-2015 02:15 PM

Car shopping

Originally Posted by shertex (Post 3453587)
At the risk of being a bit of an interloper (I don't own a CDI yet), I am interested in people's thoughts as to how to balance the mileage/price issue. Assuming well-documented maintenance in all cases, where is one likely to get the most bang for the buck? And at what mileage does one begin to incur significant risk in terms of maintenance costs going forward?

I suspect I'd be willing to spend a bit more to get something in, say, the 150k mile range. But I wouldn't be averse to buying one with 250k miles for the right price.

There is a well-maintained one where I made some inquiries with 260k miles asking $8000. Sounds fair but not a GREAT deal.

Car shopping:

I set up a spread sheet. With the following columns:

Year / State / asking price / miles / years to 300k ( for us it is 25k / year ) / purchase price divided by the number of years / a column for each available option / VIN / link to the ad

The purchase price per year of service to 300k gives me a relative cost comparison between different mileage cars. When they get to 300k, they will all have about the same relative salvage value.

For example:
2005 320 CDI / Texas / $10900 / 173,000 miles / 5.08 years to 300k / $2145 per year of service
2006 320 CDI / Arizona / $18995 / 80,000 miles / 8.8 years to 300k / $2158 per year of service
2005 320 CDI / Texas / $10998 / 113,000 miles / 7.47 year to 300k / $1473 per year of service

The first 2 cost about the same per year of service and were at the high end of cost/yr when I did this spread sheet in Jan. 2014.
The 3rd one was the lowest cost per year of service at that time.

That is just a starting point. Then I look at:
My budget for this purchase. I pay cash, so the $19,000 car was more than I wanted to tie up in a car.
The options on the car, including color in and out.
After I have decided what cars interest me, I look at the car itself, it's service history, carfax, PPI.

When I did this in Jan. of 2014, I had 32 cars listed. Doing this gave me a good sense of what was out there.
Of the 32 cars, here are the numbers that had the following options
873 heated seats - 26
530 Sat Nav - 21
819 CD changer - 19
540 rear screen - 23
297 side screens -14
433/4 dynamic seats - 6
443 heated steering - 1
889 keyless go - 3
413 panoramic roof - 2
220 parktronic - 2

The result of this shopping event was a 2007 ML 320CDI because my wife wanted AWD.

So, this Feb, when I came across a local 320CDI in Titanite Red, with leather heated dynamic seats, panoramic roof, Sat Nav, CD changer, Active Bi-Xenon head lights, new tires, 2014 Navigation disk, 196k, for $6995, I bought it.
If it was white, silver, or black, non-heated regular seats, standard sunroof, I would not have given it a second look because I didn't need it, but at that price, I could want it. That's just my opinion, it has no bearing on what you should do.

chronometers 03-16-2015 03:32 PM

Greg -- Sounds like a great price! How many miles did yours have? What maintenance/repairs had been done on it prior to you buying it? Have you done any maintenance/repairs? Are you going to run WVO with it?

spark3542 03-16-2015 04:17 PM

I'll add my data point

2005 E320CDI purchased July 2010 for $17,100 on ebay. 130,000 miles at the time, vehicle was in NC, and I have evidence that it spent it's life near Duke Univ. It was considered a steal for that priice, even with the "high" miles. I have run it since that time on almost stricly homemade BD, with the only exception being blending of various proportions of D2 in subzero winter months to keep from gelling.

I now have 245,000 and still going strong.

What I have added:
- Bully Dog fuel rail chip
- Universal heated seat ($100 Amazon IIRC)
- Trailer hitch

What I have replaced:
- Dealer replaced faulty SRS airbag wiring...$700
- Front left wheel bearing fused itself to the spindle. Replaced spindle with used part.
- T'stat stuck open. Easy to replace.
- I think only one glow plug so far.
- In-tank fuel pump at 167,000 (dealer-only part...$600)
- Turbo grenaded itself at 235,000 ($700 online)
- AT fluid and filter replacement at 200k
- Lost one "bank" of third brake light (it has about 5 "banks" of LEDs). Resoldered to get most of 5th bank recovered.
- Water pump

I do all my own work, except for the airbag wiring. SBC brakes are no problem if you disconnect the connector before working on them. I run Rotella T6 5-40 synthetic, changing at the 13k interval. I use a harbor freight vacuum pump to change my oil from the dipstick tube. The oil pan plug has never been removed.

While the list above may look long, over the course of 115k miles it has had very little go wrong. The only AAA tow was when the fuel pump died (while wife had it...which took some "damage control") This car is awesome. I'd buy another in a heartbeat.

I get about 32 MPG on average of city/hwy, running creative fuel.

engatwork 03-16-2015 04:26 PM

I test drove an 06 model about a week ago at local MB dealer. 151k miles with asking price of $13,100. I am sticking with my 98 E300 (118000 miles) for the time being. My daily driver remains one of the 95 E300 for right now.

shertex 03-16-2015 10:21 PM


Originally Posted by chronometers (Post 3453659)
To start, go to the MB web site: There are always 6-12 vehicles nationwide at various dealers. They turn over fairly quickly so if one catches your eye, call and talk to someone.

When I search the inventory at, nothing comes up. Is there another site to check?

jay_bob 03-16-2015 11:33 PM

The pre owned site is Mercedes-Benz Pre-Owned Vehicle Search

Be sure to uncheck CPO only first, there are no 05-06 that qualify for CPO and clearing this resets all the filter choices.

Also do not hit the browser back button, use their internal return to results button.

shertex 03-17-2015 08:26 AM

I like the idea of buying from a dealer with about 150k miles.

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