ROLLNNN

Hey Everyone,
I'm considering buying a w251 but wanted to ask you guys a couple questions first. I've tried to do some research but not sure that has cleared anything up for me. I guess the main question is which year/model do you think is the most reliable? When looking at these, what is the main thing to check up on? Right now, the lower mileage ones I've found are the older 2006-2007 models. I've seen a few with 60-80k. Ive also seen one or two 2011 and newer with a little over 100k miles. What are your thoughts on that?

Thanks in advance....

efzauner

lots of problems with the early models. I owned a 2008 CDI and now have a 2011 350 Gas. Try to go for a p ost facelift so 2011 or later.
Stay away from the diesels. Lots of problems and very expensive to fix.

Either way common issues are rear liftgate latch problems (replace with cheap aftermarket) , Various SAM issues. AC issues. You will have to changer rear airbag suspension probably (get the Arnot, easy to replace yourself)

Do get it checked out by a good indy shop.

Tsumi

Anything older than 2008, plan on rebuilding or replacing the transmission if it hasn't been done. If looking at gas, you want 2009 or newer unless you want V8 power in the R500, which was only made in 2006 and 2007. Other issues span all model years.

ROLLNNN

Thanks for the info! I will definitely do a PPI on it. I can handle the common issues(hopefully, lol) I was considering the older models but only the r500. Do you know of any major problems with these? I would probably go with this or a facelift r350.

Tsumi

The main big money item on the R500 is the transmission. See 7G-Tronic valve body issues. Otherwise, the M113 engine is a solid engine that routinely goes over 250k miles in the S500s.

Tailgate latch and lift mechanism and water intrusion into the spare tire compartment are the other common trouble areas I can think of. Water intrusion is especially problematic with Keyless Go because the Keyless Go module sits at the bottom of the spare tire compartment.

Oh, and the HID projectors on cars with the bi-xenon option have a habit of burning out the reflector surface. I have a thread on how to replace the projector with a better one. The replacement works for halogens too if you want to upgrade to real bi-xenon projectors.

ROLLNNN

Thanks for the info. I'm finally ready to pull the trigger on one of these but I think I'm going with a R350. Im looking at a 2009 R350 in a couple days. Anything I should look out for? Is this a good year to get?

Thanks again for the help...

Tsumi

Check the spare tire compartment for leaks. Other than that, the usual maintenance checks. 2009 should be outside the ramge of the early transmission and engine issues.

ROLLNNN

OK sounds good, Thanks!

Trampas

+1 to everything ezfauner said. 2011 is the single best year I think, includes the facelift and LED lights which are huge upgrade--but retains the same bulletproof v6 engine before it was changed in 2012. Make sure you have good indy mechanic lined up to service it when you buy, although ours has been extremely reliable. Bought w/55K miles and now has 85K, taking only a thermostat replacement and new tires. Hope to keep it running reliably till at least 125K, and let 2 very young kids beat on it in the meantime. It is an incredible vehicle and is a joy to do 500-1000 mile road trips in.

chassis

@ROLLNNN Update?

ROLLNNN

Nothing exciting to update. I test drove a 2009 r350 a little over a week ago. I liked this specific one because it had keyless go, which I really want. The only problem is, the motor didn't sound very good. I'm no mechanic but, the belts were squeaking pretty bad and there were other noises that didn't sound too good. It sold the next day, lol.

I've been thinking, i might want to get a R500. I'd like a little more power, but just want to make sure its reliable. Right now I'm open to either one, just want to get a low mileage(under 100k,) 2009-2011 350 or a 500. Must have keyless go(hard to find) and heated seats. There aren't very many for sale in my area, so I'm not really expecting anything soon....

Tsumi

R500s are more likely to be optioned out but also have the first iteration of the problematic 7g-tronic transmission. Either make sure the transmission has been rebuilt or budget in a transmission rebuild if opting for the R500.

Tirefriar

I owned a 2007 R350. From the issues I experienced the biggest by far was the rear airmatic suspension. My wife insisted on diriving the car even after the suspension was sagging and the MIL came on. In the end burnt out the compressore. Ours was equipped with rear airshocks only, front was conventional. Replaced the rears with aftermarket units, compressor was replaced under extended warranty. Keep in mind that any used cars can and most likely will have issues with electronics. I owned a BMW E39 Touring with air shocks in the rear which also gave up a ghost but at a much lower mileage than the MB. There are very few vehicles out there that can match the w251 for its versatility and options, just look at the size of the pano roof and the three row seating with captain chairs in the 2nd row. Add to that a 4matic and you have a great year round travel wagon for your entire family. Just make sure the services are up to snuff and you are good to go. BTW, our R350 was a frequent LA to Las Vegas flyer. Plenty of power and the rear active suspension offered a "magic carpet" ride...

Tsumi

Technically, the rear air bags are just for load leveling. Only the 4 corner air system gets the adaptive suspension.

One other annoying thing about the M113 engine is the tendency for the valve cover gaskets to leak. I've replaced it twice; the first time with Elring and the second with OEM Mercedes. Still leaks. I've seen some posts where they said they filed down the bosses on the valve cover to get it to seat tighter. Others mentioned using gasket sealer. I'm going to try the gasket sealer and see how it does.

Generally I leave the adaptive suspension in auto, and it comfortable enough most of the time. If I feel like pushing it through an off ramp at high speed or carving through some mountain roads, I'll put it in sport mode. I only use comfort mode for long straightaways, i.e. i-5 in CA. It's too boaty in comfort mode for commute driving but simply floats on straightaways.

I got the OEM hitch for it and had a local shop replace the Class II receiver with a Class III receiver. Super comfortable towing our boat and you can hardly feel it back there (boat + trailer weighs about 3700 lbs).

ROLLNNN

Thank you for all the info guys! I've been looking but can't seem to find any low mileage(under 100k) optioned out, 2009-2011's in the LA/OC area. I've found some low mileage, like 60-80k, but they are older 06-08 350's. Should I totally stay away from those years?

I know the air suspension has been mentioned as a big problem, but that is not something i need to worry about. First thing I will be doing is a coilover swap and lowering with wheels. With that said, should I still stay away from the 06-08 350's?

Thanks.

Tsumi

Car market has been barren for the last year in general. It's not unique to the R class, though the relative rarity of them doesn't help.

There are two types of air suspension on the W251s in the US: rear only for load leveling, and 4 corner with adaptive suspension. Honestly they're not that big of a problem. You just have to plan for it as a maintenance item rather than an expensive repair. Rear air springs are $60-160 on RockAuto, depending on the brand. If you notice your car sagging, you should replace them ASAP because it can burn out the compressor otherwise. Though like you said, you can swap to coil springs and not have to think about them at all.

06-08 have these two major problems to think about: balance shaft failure on the early M272 engines and conductor plate failure on the early 7G-tronic transmissions. If you buy into those years and none of those have been addressed, make sure you budget for these repairs. Everything else on these cars are basically the same throughout the years.

qman56

2005 -2012 Defective balance shaft. 4-6k repair out the gate if it has not been done. MB class action suite settled in 2014 but too late for you to get any relief. The M272 engine it these years, all model years with this engine have this issue. I missed the deadline as well. Cost me 6k.

ROLLNNN

I thought the Balance shaft issue was only for MY2006 - mid/late 2008. Are you saying every year m272 has the issue?

Tsumi

Get your facts straight. The lawsuit only covered 2005-2007 model years. The lawsuit was also settled in 2015, though that's a minor detail.

The balance shaft (and any other part for that matter) can fail on any engine. Wear and tear will do that. 05-07 had a significantly higher rate of failure, hence the lawsuit.

MelKaz

Last year we purchased a 2008 R350 with 125,700 miles. It was an original owner car and had been beautifully maintained. We had had a 2006 R350 a number of years ago and loved it and my husband had been searching for another - we actually traded in a 2014 E350 Coupe for it (the dealer owed us money LOL) - we love this car - we are older and retired and have had a number of other Mercedes over the years and for our needs today it is a great car. It does not have air suspension - it does not have a panoramic roof - but all the other options. We have an independent shop here that we can use when and if we have any issues with it - so far it has only needed a new battery. The location for the battery is under the front passenger seat - what were they thinking - but the key is finding a vehicle that has been well maintained and from the original owner if possible or with all records.

ROLLNNN

That's great, I'm sure i will love it as much as you do. I just hope i can find a well maintained one. Right now there just aren't very many choices but I think I finally found one. It doesn't have every single option I wanted but it is low mileage and seems to be well taken care of.

ROLLNNN

I just wanted to say THANK YOU! for all the help to everyone here. I finally found one and picked it up today. There weren't very may clean ones with low mileage in my area. The main option I wanted was keyless go, but those are very rare and unfortunately couldn't find one. I'm pretty happy with this one though. Its a 2008 R350 with 84k miles. The engine number is past the ones that have the balance shaft issue. I had a ppi done, it had couple issues but nothing serious just some normal maintenance things. Some mods coming soon..

ROLLNNN

So 3 days of ownership and my first issue has come up. You guys have mentioned hatch problems many times, but I can't seem to find this exact problem. The hatch opens and closes fine, but after it closes, I get a message on the dash saying it's still open. I have to open and close it another 2-3 times for that to go away. The first 3 days I had this thing, It was working fine. It started this morning and now it happens 75% of the time. Do you know what this can be?

Thanks!

Tsumi

Congrats on your purchase!

As for the latch, the latch pulling mechanism might not be pulling it in all the way. Do you notice any differences in the tailgate gaps between when it does and doesn't give the warning?

ROLLNNN

Thanks! I appreciate all the help.
To answer your question, No there were no difference in the gaps. I checked a few times to make sure it was fully closed when getting the warning. It was fully closed every time...