sdwtchlvr

I have opportunity to purchase a 2007 SL550 from a family I've known and worked for over the last 18 years. The car belonged to their late father who purchased it new. As far as I can tell, it has the Designo leather package (white exterior & white/black interior), AMG Sport Package, Pano roof, Distronic Cruise. This is what I can discern from photos but I can't be sure until I see the car in person later this week. I remember when he bought this SL550 and he loved this car, drove an older version many years ago when I met him in the mid 90s.

This SL550 has 78k miles and though I know it was maintained with an open check book, I don't know that they have many/any of the service receipts. The car is in Central CA and I'm in Southern CA, I am flying up this weekend for it. I have an appt. this coming Monday morning for a PPI at a well-regarded Mercedes Indy shop in the same city as the car and will have them look the over it thoroughly.

I do know that the trunk leaked at some point recently (known fault with this car) and they just spent $6500 at an Indy replacing the PSE system and resealing the trunk. I’m sure they over paid but it involved many hours of troubleshooting according to the invoice. From pouring over numerous threads on this forum, I know my main concerns are the health of the ABC system, SBC system, batteries, PSE system.

I’ve driven Lexus exclusively for the past several years and my current line up is a 2009 LS460 and 2001 LX470. The AHC hydraulic system on my LX470 failed this year due to fluid contamination (by previous owner) so I decided to replace the entire system with the OEM Landcruiser suspension set-up and haven’t looked back. I understand there is a similar suspension swap possible for the SL550 if the ABC system fails?

I realize that maintenance is going to be more expensive/extensive and I’m fine with that, to a point. I’m getting the car for very generous price which allows me to budget for some unforeseen repairs if need be. But I’m assuming this car’s best years are behind it as far as trouble free ownership?

I’m not really a big DIY guy but I can change fluids, change pads/rotors, batteries, things like that. My neighbor a few houses down owns a very respectable Mercedes repair shop in town so I feel fortunate to have his guidance as I’m sure I’ll need it, all big repairs will go to him. I’m quite resourceful when it comes to researching error codes & fixes for common issues. I’m not afraid of used/reman parts. From what I’ve read, there are plenty of folks that have these cars and have them repaired for much less than what a dealer would charge them.

I just wanted to put all of that out there and see what comments come in. Thanks for reading.

Rudeney

Welcome to the forum! A one-owner California car is always what I look for in used car - no rust! Have you check the VIN for potential "balance shaft" issues? On the V8, it's not an actual balance shaft, but the timing chain idler sprocket that can fail. Post the VIN and I can look it up for you to see if it's in the range for potential failure.

Another concern is with the transmission. Prior to MY2008/2009, the 722.9 transmissions had problems, especially with bad speed sensors. When you get the PPI, see if they will give you the VMI. If they are concerned about it showing the prior owner's info, ask that it be redacted, or cut off the pages. You want to find out if the transmission conductor plate was replaced. Listen for whining noises coming from the transmission at idle - that's a sign of a bad fluid pump and/or torque converter.

The roof hydraulics can fail with age, but if you can do brakes, you can probably do that and you can either rebuild cylinders yourself or buy rebuilt ones for a fraction of new parts prices. Speaking of brakes, know that any brake work will require disabling SBC. It's best to do that with SDS, but it can be done "manually".

sdwtchlvr

I appreciate the comments. The PPI is being done at an Indy so I don't know if they'll have access to the VMI. As I mentioned, I know the family quite well and would consider them my extended family...perhaps I could ask them to contact a Mercedes Dealer for the VMI. Would an Indy have access to that?

That's a bit disheartening to hear about the possible transmission issues. I will definitely ask the PPI shop, major component issues (engine, transmission, ABC) are what I'm looking to avoid. The vin is WDBSK71F97F126457.

mercy-me

Previous owner should have no problem requesting a VMI report from the servicing dealer which they can do on the spot or even email it to them or you. I'm attaching the Data Card which shows all installed equipment. Looks to be a wonderful car which you will greatly enjoy.

Good luck,

Bob

Rudeney

Only a MBZ dealer can pull the VMI. Bob's suggestion to have the current owner ask for it is a good idea, although they still might not do that. Looking at the data card, the engine is in the range for potential "balance shaft" failure. That does not mean it will fail - a very small percentage actually do - but it is a possibility. If the transmission has not had its conductor plate replaced, it surely will need it.

sdwtchlvr

Thanks for that Bob, so the SA Code is detailing all of the equipment/options installed on this particular SL550? That's great, just what I was looking for.

The owner now is the original owner's daughter who inherited the car. I don't know that it was serviced at the dealer out of warranty but I'm sure it was while in warranty. Can she call any Mercedes dealer or does it have to be the dealer that serviced it? I'm guessing they all share the same network of data?

Where can I find more information on the conductor plate? I'm going to search the forum but if there are threads that are better than others, that would be helpful. If there are no records of the conductor plate being replaced, would there be a way for a shop tech to tell?

Rudeney

Any MBUSA dealer can pull the VMI.

The conductor plate has to be replaced because of speed sensor errors. It's a dealer-only job due to it needing SCN coding (it's part of the car's anti-theft system). Symptoms start with it going into limp mode (stuck in 3rd gear with no torque converter lock-up).

sdwtchlvr

This seems to be fairly good information, would you say so?

http://www.mercedesmedic.com/must-re...nductor-plate/

In doing a little bit of reading, I'm guessing that if/when the conductor plate goes south that it might be a good idea to also replace a few of the surrounding parts including the valve body and TCU? So the only option is for the conductor plate to be replaced is by a MB dealer? That's disheartening. I've read that it's a $1200ish job which isn't too bad but I've also read that guys have done the job themselves at home. How is that possible if they are needing SCN coding? Would an indy shop not be able to do it if they have the proper Star scan tools?

Rudeney

Yes, that is very good info. As for replacing other parts, originally, MBZ was replacing the whole conductor plate and valve body as a single assembly, but then they discovered it was not necessary to replace the valve body as the problem was only in the conductor plate. The TCU is actually made into the conductor plate, so it's getting replaced when they do the job. The reason why this is officially a dealer-only job is that the TCU must be "SCN" coded. This is a process where the VIN is coded into an electronic part using SDS (the dealer's Star Diagnosis System). While it is possible to buy a Chinese clone version of SDS, only a live version licensed through MBZ can do SCN coding. I have heard of some people using "development mode" in the Chinese SDS and manually calculating the encryption key from the VIN. I have also heard of some people connecting with an MBZ tech who moonlights and will let you you his license to download the code. But yes, it;s about a $1400 job at the dealer.

sdwtchlvr

I should be able to get the VMI soon enough. But I ran a carfax with the vin and got some info on previous services.

It looks as though the Power Steering pump was replaced at the MB dealer in May 2012 and during that visit the engine was cleaned, steering/suspension checked. So would the ABC pump be replaced at that time too, aren't they connected?

And in April 2012 the Hydraulic Control Unit was replaced and brake fluid flushed at the MB dealer, is that the SBC brake unit?

I don't see anything on the carfax about the transmission conductor plate but there aren't a lot of details on the report and there was some work done at indy shops too. Hoping to get all the details in the coming days.

carguyshu

yes the power steering pump and ABC pump are the same. The hydraulic control unit would most likely be the SBC. Be prepared to replace all the accumulators (hopefully at least the one on the pump was replaced at the same time as it is much harder to get to on the ABC II system you have vs the original design), as well as the 3 hoses that run in the engine compartment. These things degrade as a function of time and heat. Mileage doesn't have a big impact. Replacing these would be a wise idea as prevent maint. as you can blow that new pump pretty quickly if/when one of those go. These 3 are the ones that go first since they are pressure lines and are subjected to the most heat.

You should also prepare for a new front latch on the top (if it hasn't been done), trunk flap fix, trunk latch closer, top hinge flaps, upgrading the shifter mechanism from plastic to metal, idler pulleys, & delaminating rear plastic trim on the top. The front suspension bushing on the lower control arm also only last about 40k and with you nearing 80k they likely need replaced too. You can replace just the bushing and don't have to buy the whole arm.

sdwtchlvr

Thanks for the feedback. I'm hoping to get more details on the actual services once I get the VMI. I agree that those hoses should be replaced as preventative maintenance and I'm guessing I should do that and have the system flushed at the same time?

Another question, I called the nearest MB to the car (45 minutes away) and they do pre-purchase inspections for $160 while a local shop that I had an appt. at charges $150. Would it make sense to get the PPI done at the dealer vs. indy shop? I'm guessing it would but wanted to hear your feedback. The dealer has actually serviced the car before and did the SBC job I mentioned before along with other random services. Is it a no brainer to take it to the dealer for the inspection?

Rudeney

Take it to the dealer for the PPI. And while there, ask for the VMI.

carguyshu

have the dealer do it as they can hook up the car to the STAR system (it is the diagnostic system used by the dealer to service the car) and see if there are any problems the car is self reporting. the indy likely does not have star and thus is more likely to miss something (for instance on my SL55 there was a recirculation door motor that had gone bad that I had no idea was the case until I hooked the thing up to STAR and it told me).

Yes the fluid should be changed on the ABC system when you do the hoses and you will save a bundle if you buy the fluid in gallon jugs on amazon. you will also want to replace the filter. to properly and fully get all the fluid out of the system there is a bleeder valve near each ABC strut that needs opened and the fluid let out. Fluid between the valve block and strut and in the strut otherwise will not be replaced if you do not do this after the system has been flushed. this is a detail most people and shops miss or don't know to do

Rudeney

I would not replace hoses as a preventative measure. I would wait until the leak. It's not a given that the hoses will fail, and there is no guarantee that a new hose won't have a defect that causes it to fail early. Just make sure that if get ABC warning,s you are prepared to pull off the road and shut down the engine ASAP and have it towed. Don't drive it with ABS errors as you can destroy the pump which in turn can spew its pieces into the system and damage vale blocks and other parts.



The fluid should be flushed and filter replaced according to the WIS docs. And I totally agree on bleeding at the struts!

Eliroc

Hi Rodney,

I am considering purchasing a 2007 SL 550 with 50,000 miles. VIN = WDBSK71F47F119996 Can you kindly check if the engine is in the range for potential "balance shaft" failure. Additionally, is the conductor plate failure to be expected for all 2007 sl 550’s? Thanks in advance.

Rudeney

WDBSK71F47F119996 has M271 engine #025191, which is int he range for timing chain idler sprocket failure.

Eliroc

Rodney,
Your help is greatly appreciated.

Many Thanks,