ROLLNNN

Hey Guys & Gals,
I'm considering picking up a w209 non AMG(320, 350, 500) Cabriolet as a daily driver. Im hoping to get some tips from you guys before I do. I'd like to get a facelift 2005 and newer. I've read I should stay away from the 2006-2007 models? Is this correct? Any other suggestions?

Thanks in advance!

DanielFD

Its not really a "stay away" kind of thing but on the 2007.5+ models your free from having the risk of a balancer shaft issue on the 350 and camshaft adjusters on the 500/550 also the 7 speed transmission are more reliable 2008+ with revised parts and so on. a good deal would be 2009 model (last model) you can find 350s with an amg kit and steering pedals(we all love steering pedals). If 2008 and 2009 clks are out of budget and you dont want to risk it, a 2005 CLK320 is golden with the updated interior and the solid m112 engine mated to the robust 722.6 5 speed trans.

Yidney

Other than to get an '08 or '09 no real tips. Mine is a daily driver year round, and I don't live in Cali.

omega48er

Once you go w209 it's hard to drive anything else hehehhe

Rudeney

Being in SoCal, you'll definitely enjoy a cabriolet as a daily driver. All the issues discussed above regarding the early 722.9 transmission and "balance shaft" are right on. I echo Daniels suggestion for a MY2005 CLK320 to avoid those problems. Regular maintenance is not terribly expensive - on par with the C-Class on which the car is based.

The only other thing I'd say is with a car this old, the soft top may be near end-of-life. The seam that runs across the top just above the rear glass is know to fail. It's glued together with an adhesive that will become brittle, crystallize, and let go. It really cannot be repaired from the outside. The best option is to replace the entire canvas. Unless you can handle it as a DIY (it's a two-day job), then budget $3K or so for the job ($1K for a Robbins canvas, $2K for labor). Another alternative is to peel back the top to expose the seam and repair it with new adhesive AND stitching. This will be less labor intensive (I'd say 70% of the labor is around the rear glass) and save you $1000 on new canvas.

merceBENZ

I have 2006 with bulletproof M113 engine. Transmission has been done by previous owner. Can't be happier.

merceBENZ

Yes, on top of that I have rare color combo. Win-win everywhere.
Shop wise. I got mine if Craigslist.

Rudeney

I assume you mean that the conductor plate was replaced? That is the primary failure (in fact, it may fail on all 722.9's int he early build range). However, there are other points of failure on these early (pre-MY2008) units. The torque converters were crap. The lock-up clutches in them will deteriorate and throw particulate into the oil. The fluid pump was also a weak point. It used a sleeve bushing instead of a needle/roller bearing where the torque converter attaches. This bushing wears and causes multiple problems. the Most benign is a whining noise. It can also cause the inner pump gear to "wobble" which cases it to score the magnesium bell housing surface that it sits against. Eventually, the gear will break and you will have catastrophic failure, pretty much requiring a transmission rebuild or replacement.

I'm not try to scare you (or anyone with an early 722.9), but after being inside mine, I now understand what happens here. It's a shame, because otherwise, these are solid units. I'd say a MY2008 or later and you're good, but before that, it's a crap shoot.

ROLLNNN

Thanks everyone for the posts. This information is exactly what I was looking for. I currently have a 2005 clk55 that's in my signature and love these cars. I really just want something that is going to be as reliable as possible. At first I was looking for a 2005 clk500, but read about the transmission problems. Engine power is not really a big factor for my daily so I think I'll check out the 05 clk320's. The only problem with these is they don't really come with the options i want. If it didn't have keyless go, heated seats and bix, it was a deal breaker. I guess i'll have to rethink that.

If there is anything else you can think of please let me know... Thanks again!!!

ROLLNNN

Hey Rudeney
does this seam deteriorate & separate over time and is something i can notice before purchasing or does it just tear apart all of sudden?

Thanks..

merceBENZ

You are right about that. But it is not very common failure as balance shaft. Nor that expensive.

Yidney

You can pretty much tell if it is already coming apart just by looking at it, but you cannot tell what it may do tomorrow or next month. Mine sits in the high UV Colorado sun 24/7/365 (never garaged) and so far it's fine.

Rudeney

If you are talking about conductor plate failure, it is very common and I believe that they all will fail. It was a faulty Siemens speed sensor. It is not as expensive as a balance shaft repair, though. Most USA dealers charge about $1400. As for the torque converter, again, all early ones have issues due to the material used in the lock-up clutches. They may not fail early, but they sure put a bunch of black particulate into the fluid and that's not good for the rest of the transmission. Finally, the fluid pump is also a certain issue on all early models, though premature failure is rare. The sleeve bearing simply won't last. It might take 200K miles for it to fail catastrophically, but it eventually will.

Why will the pump fail? Let me explain. Here's the pump:



That inner gear is driven by a shaft that is part of the torque converter housing:



The torque converter is bolted to the engine flywheel and it always rotating when the engine is running, thus the transmission fluid pump is always operating when the engine is running. This is a very common configuration and most all modern automatic transmissions will work this way.

The red ring you see in the bottom of the hole is the seal. Just above that is the copper busing (sort of rust colored) that the torque converter rides against. It, and the torque convert shaft, will wear. When it does, it puts additional stress on that pump gear. The gear surface (the one you can see in the photo), rides against the surface of the transmission bell housing. When the torque converter starts pushing on the gear at odd angles because of the worn bushing, it will score that surface (the bell housing is magnesium, which is very soft). Eventually, the scoring will let the pump gear get "locked" and then it will break. Now, you will have metal chunks in the transmission and you need a new (or rebuilt) one.

As for cost, I fixed all this myself (before it got too bad), for well under $100. At dealer prices, they will charge over $100 just to drop the transmission. They won't open it to repair the pump - instead they will sell you a new (or rebuilt) transmission. Expect to pay about $5K in install a rebuilt, or $8K for a new one.

All of these early 722.9 transmission (I'd say prior to MY2008) on all MBZ cars have these issues. They may last 200K or 300K, but they are all going to fail.

merceBENZ

That's is very depressing! Now you are making me nervous. What do I do? What am I waiting for? When it is time? My car is 45k only..
Thank you for VERY detailed write up. I'm sure going to save it for my future references. I really hope I won't need it. But I'm really uncomfortable now.

Rudeney

Like I said, it may be a long time before this fails, but it will happen due to the design. One of my local indy shops says they see less than one a month where this has happened. But as these cars age, it will become a more common failure. And then there's the argument about, "at what age is it considered premature failure?" I think if it fails at 100K, it's "premature", but what about 200K miles? 300K? There are 5 or 6 pre-MY2008 MBZs in my office parking lot, and all of them have the tell-tale whine.

merceBENZ

That's terrible QC from MB side. They need to put their suppliers straight. Total waste of money.

Rudeney

Suppliers have been MBZs quality problem for years. The "balance shaft" failure problem was due to a supplier's lack of QC when forging/hardening those parts. I was never privy to how MBZ makes agreements with suppliers, but I always got the feeling that they had some sort of agreement that limited supplier liability.

merceBENZ

That ruins MB name and reliability trust. For some it will be a deal breaker. Oh well, nothing built to last nowadays.

abqhudson

A low mileage 2005 CLK 320 would be a wonderful car - if you can find one.

merceBENZ

CLK500 has better options such as advanced climate control, directional fog lights etc

JimVonBaden

What would be considered "low mileage"?

merceBENZ

That is a good question because everybody has their own definition of that.

Rudeney

Personally, when buying a use MBZ, I prefer something between 25K and 50K. I don't like very low mileage cars, because they weren't driven enough to get all the bugs worked out under warranty. Since I usually keep a car about 5 years, at 50K, I can come in under 100K miles during my ownership.

Rudeney

I do need to apologize for hijacking Roland's thread. I did not mean for this to turn into a ***** session about MBZ quality or a thread about transmission woes. I do want to clarify one thing about the discussion, though. I have been pointing out problems with these cars and the root being supplier quality failure. So, does that mean I am recommending buying MBZ vehicles? Actually, to the contrary. I actually like MBZ vehicles very much and I will continue to buy them. I love the way they are engineered and I actually find them easy and intuitive to work one. Bu the best thing I like is the ability to buy one that is just out of warranty (about 4 years old) for less than half the price of a new one. Yes, all of those quality issues means they lose their value quickly. For those of us who are willing to learn to DIY, its a great opportunity. For anyone considering buying a used MBZ and needing to rely on the dealer or an indy mechanic, well, make sure you have the budget for it!

ROLLNNN

I've found a few in my area between 60k - 90k. Gonna try and check out a few this week

So true. I happened to drive by a small used car lot which had a 2006 clk500 cab. It basically had all the options i wanted, bix, keyless go, electronic climate control, heated/cooled seats. I walked away without even inquiring about it.

No need to apologize, I love reading all the information you post up..