SL550 Expensive to Maintain!
 

2008 SL550 with only 38k miles.

Since 2013 these are the following repairs I have had done:

-Vario roof hydraulic pump replaced ($2054.00)
-AC Compressor replaced ($2100.00)
-Driver's side SAM replaced ($729.00)
-Convertible top flaps replaced ($697.00)
-Right cylinder head replaced ($4437.00)
-Engine and transmission mounts replaced ($1600.00)
-Rear engine oil leak repaired ($500)

Verdict: Wow these cars are expensive to maintain! This does not include the money spent on routine maintenance (oil change, air filters, etc.). Extended warranties are a must have.

Any SL owners out there with similar repairs?

Appears this car has had a tough past. Or maybe some other problem. Really 38K miles?

Certainly should not need a cylinder head. And most likely not engine and transmission mounts, rear engine oil leak, AC compressor. Top flaps can go at any time. I wouldn't pay $700 for that. There are six nuts on 6mm studs. A rack and a spur gear are the flap replacement parts. Time to repair 20 minutes each.

You bought a very neglected car, or I think you need to find another service professional. Dump it off. This is just the beginning for you.

Someone rode that car hard. That's way out of the norm.

I have the extended warranty. I haven't paid for any of the work. Car would have been gone a long time ago if these were out of pocket expenses.

The cylinder head had to be replaced due to a misfire in cylinder # 3. That was my main concern. But it runs like a champ now.

AC compressor having to be replaced seems a little early also.

But everything else seems to be typical things going wrong after reading threw many of the post for this car.

Vario top problems seem to be the norm. As do engine mounts wearing out.

You seem to love your car. And it is good that you have the warranty. And I do hope you get it all sorted out while under the warranty.

It might be a good idea to have a very reputable and knowledgable service really give it a good close check up, and maintenance service, well before your warranty is up. Get a service history report from a Mercedes dealership. That, at least might, show you what Mercedes service it has had under the factory warranty.

The problems this car has presented are NOT normal, at that age and mileage. And indicates there is something in your cars history that is not being disclosed to you. Accident? Or maybe just a questionable service facility, that knows how to "work" the warranty company.

Other than the roof flaps, those other things just don't fail without provocation after 38K miles, and 6 years of age.

The cylinder head causing a mis-fire? Indicates a cracked head. Generally a crack in an Aluminum head will occur within the factory warranty period. A manufacturing defect. Otherwise, maybe the car ran out of coolant, and overheated. Or the car was not sufficiently antifreeze protected against freezing during winter, and froze up.

Other reasons a cylinder head could contribute to a single cylinder mis-fire. Head gasket fracture. Bent or cracked valve. But neither of these reasons truly justify REPLACING the head. The ONLY justification would be...."Hey the warranty company will pay for a new head, so why not get them to pay for it?" Or maybe..."The warranty company will not pay to replace the head gasket or valve replacement, unless we replace the cylinder head."

Of course other and more likely causes might be spark plug, or ignition system issues. But I wasn't there so I really shouldn't be second guessing someone else's work. But if I were you I might be a little sceptical of what is the real past/presentstory with your car.

Hope you have it all sorted out, and it gives years of trouble free enjoyment.

I would not own one of these cars without a warranty. Parts and labor are very pricy. I will be selling this car before the warranty expires.

Yes, the cylinder head was listed as being replaced due to manufacturing defect. Guides and seals were also replaced. They were listed as being worn. Which I am guessing caused the misfire in cylinder # 3. It was shaking and running very rough at the time. Runs great after being replaced.

It is very possible the stealership is taking the warranty company for a ride.

I took it to a second dealership for a second opinion on the motor mounts. Both told me this was a very common problem with mercedes V-8s and after reading numerous posts on this forum it seems to be a very common problem.

I am always skeptical of dealerships especially when they know it is covered under warranty.

Thanks for all the info. You seem very knowledgable about these cars.

You have a good understanding of things.

And you are correct as to the motor/trans mount issues. Just seems to me that it's a little early in the life of your car. But maybe not totally unusual.

The cylinder head, may have been a manufacturing defect. Just surprised that it would take 38,000 miles to show up. But thinking about it, if the guides eventually wore enough so that the valve head would not effectively seat, it would cause a mis-fire. That needs to be worn quite a bit to cause that issue. They call it factory defect. Good.

However, I suspect differently. Maybe hydro-lock, over reving, (rev limiter???), timing chain issue, or some other form of abuse to bend the valve. And once the valve head got bent, it would wear the guide, so the valve won't seat. Kinda works backwards to the theory that the guide wears and then the valve head becomes unseated.

I know how heads are manufactured. My company has made the tools that drills, bores and reams, the valve guide holes. And the same tool, also cuts the triangle seating surface at the same time. This is so centrality tolerances can be held very close, and is reliable though out a production run. And post process gaging is used to ensure that each hole, and the related bores and surfaces, is correct in size, position and relationship to each other. We're talking millionths of an inch, between different diameters, planes, dimensions, . These tools are made to be the correct size. They don't allow any machine operators to make any adjustments. And if a tool bit begins to wear out the post process gage shuts the process down, so the tool gets replaced with a new one.

But back to your car, if they replaced the head (casting only) they would certainly need to press in new guides and install new seals. So the new guides and seals story they gave you doesn't ring with confidence. Another option might be a sub-assembly, where the guides are pressed in and machined. Now if they bought a fully assembled new head (which most dealers would do), it comes with new seals and guides installed. As with all the other stuff too. Dealers just don't want to, or take the time, (or have the technology/expertise in-house) to machine the casting and match the valves, and assemble all the parts. And besides, if they assemble the head, Mercedes would not guarantee the component. So dealers rightfully will generally choose to buy the whole factory built component assembly. And you are better off for it. So that is a good thing for you.

My bet is you got a new factory assembled cylinder head. In that case I wonder about the claim for new seals and guides. But no claim of new valves? Hmmm...

Regardless...that is all in the past. Your car is running good and all is well. Hopefully all sorted out. You did very well to buy the warranty. You certainly can feel good about that. A very smart thing to do.

Extended warranties aren't cheap on these cars, but they are a must have! It's almost guaranteed that it will pay for itself several times with the cost of repairs. I have just over 2 years left on my extended warranty, which means I have just over 2 years to enjoy this car before I trade it!

Well I can say that after 100,000 miles, the only thing on that list that has been done to my car is the engine/trans mount replaced.


And that just happened 2 years ago. Not before 38k miles!


It seems to me that you have a dealer that loves to do work and bill a warranty company. Every part on my 2003 could probably be considered "leaky" if you were looking for the smallest leak in a hose, gasket, or other part. Your dealer probably would have replaced every part on my car... yet it starts and runs perfectly fine with no leaks.


I'd say most of that stuff probably never needed to be replaced. Or there was a cheaper solution. For example, if they are replacing a pump and a bunch of hoses clamps and mounts, how do you know that the hose wasn't leaky or the pump wasn't mounted properly causing noises and leaks? Sure the pump replacement will fix it but you replaced all of the possible other parts that could be causing a problem.


I have found that dealers love to ignore slightly leaky airmatic struts. They are unnoticeable to the driver as the pump just starts running more. Car performs the same.


Then a while later, the pump burns out and car collapses. Boom: we need to replace the pump, leaky strut, relay, and the other non-leaky strut "because we only want to replace them in pairs".


What could have been a $300 strut from Arnott is now a $4-6k dealer job. They'd love for you to trade the car in cheap (book value less $6k) and roll you into a new car.. then they fix the part and send it off to auction for full auction value.


I'd find a new dealer as soon as your warranty is up. By the time they're done replacing parts on your car when the warranty ends, it will last forever since the car is now basically brand new!

Same here. 2005 SL55. 108,000 miles.

Can you elaborate on the pump running? I notice that I hear a pump running sometimes when I first start the car or turn it off. Ride height seems normal and the car has been at the dealership at least once a year and they didn't mention this. Warranty expires in a month.

The head isn't as uncommon as the other guy is trying to say. Apparently some heads have valve guides go prematurely , the valve moves and damages the head , compression drops in that cylinder and then it misfires and throws a code. I've had a motor mount fail on mine with less than 50k miles myself. The dealership will always go for both mounts and trans mount rather than do one. They also go with replacing the head as an assemble . The flaps of course are a very common issue. Having said that, your experience isn't a super common thing by any means but it doesn't mean the car was necessarily abused either. You just happened to have several things fail in a short period. Also, I wouldn't advise listening to the guy that said you should be ok when the warranty is up because so many things are newly replaced. You stated that you wouldn't own the car with no warranty, stick to that thought process. The reasons I'm not sticking to that rule are I have a buddy that's a technition at the dealership that I can trust , he can work on my car on the side,and I used to work at the dealership myself as a supervisor in the collision department and I perform much of the work on my car myself. Shortly before my CPO warranty was up I had a self leveler go bad in one headlamp ($1500.00) , the heater core started leaking ($3000.00) and a SAM in the trunk go bad ($1200.00). These issues occurred all within about 7 months and the mileage was 48k when the warranty expired. The car has always been well maintained and not abused. The extended warranties are worth every penny and almost always pay for themselves . Anyway, good luck and I'd advise you to stick to the plan and let it go when your warranty is up.

BHA is referencing Airmatic pump which cycles in and out to replenish lost air in the Airmatic system. The ABC pump is a tandem pump combined with the power steering pump as one unit which is pulley driven and spins constantly. The motor you hear occasionally is most likely the air pump on the front of the motor which is normal. There is also a chance that what you hear could also be the coolant fan motor kicking in especially if running at idle for some time.

Bob

Thanks Bob. This makes me feel much better!

I suspect you are hearing the SBC pump which is the electric pump which powers the brake system. It is behind the RH headlamp. It is normal for it to come on when you first get in the car. You can push the brake pedal without the engine running and should hear it cycle on and off as you push the brake pedal.

Does anyone else buy into a theory that when a car is under warranty, repairs will become replacement, etc because there is more money to be made and the owner is not going to complain?

My last S550 went to two shops within days before the warranty expired. Both Mercedes dealers. Both shops actually did the same work on a couple of items...