Engine Question - not VX

I was wanderring if someone can help me understand what is going on with my other rig.
I own 2003 C230 kompressor. Got it passed July with 42000 mi on it. Since then I put on it over 8000 mi.
Two weeks ago I had exhaust valve springs replaced. Dealer said that the engine light on and rough idling is due to a carbon buildup on the exhaust valve. Week later I went back to the dealer with the same symptomps. Today dealer told me they need to replace whole cylinder heads along with all valves, sleeves and springs replaced again. In one word they are planing to rebuild whole top part of the engine.

The sytuation makes me uneasy.

Souldn't they replace pistons while they are at it?
Or if it's such a big deal, that - according to the service guy - "Mercedes told them to replace this, this and that" - they should put in new engine?

This car is certified and has extended warranty. So far all repairs are paid for.
I am so close to get back to the dealer and negotiate a replacement for this car. I know Mercedes, or at least the old, good quality of it. They were never disposable. At least not after 50000 mi.

What do you think?

Unfortunately the new MB cars are pretty much along the same line of quality as their new buddies Chrysler and are approaching "disposable" status. Hopefully they'll get a turnaround and return to their reliable, value-holding roots but it's unlikely in the state of acceptable business practices. :(

But back to your question: A typical top-end rebuild is both common and straightforward. Since you mention your engine is sleeved, that feature adds longevity to the block and makes such maintenance a simple affair. The reason your pistons aren't being replaced is that the only thing that usually wears on a piston is the rings, and those will be replaced. My guess is that the sleeves may be showing some scoring as a result of debris from whatever may be happeing in the head, or as a "good service" measure by the shop. Again, not uncommon. The replacement of the head (the 230 should only have one) could be due to any number of reasons, such as warping or a known design flaw. They'll probably use a "complete" head which will already have the valves, guides, springs etc. already installed. Unless you're on the cheap you don't want to re-use that stuff anyway in regular vehicles.

So from what you've shared it appears they're on the up-n-up. Be sure to get all the warranty paperwork and verify the guarantees and such on the work, just in case. ;)

I'll back Joe up on this. MB is close to the very bottom of the list for first-three-year reliability (JD Powers), and have been on their way there for some time. Their brand thrives on its laurels from yesteryear, but they kind of suck in the reliability department these days.

If they're paying for the replacement, take it. And if you're putting cheap gas into it, then step up to a high-quality fuel. That's the only other thing I can think of that may be goign wrong with a good engine.

Lastly, a buddy of mine bought a new MB a few years back, and it was haunted from the start by some nasty electronic gremlins that would make his dash display freak out fairly often. After trying to get it fixed 4-5 times, he sued MB under his state's lemon law, and dragged it out for as long as he could to enhance their motivation to settle, and even then, they refused to replace the most obvious component - it was either the ECU or the dash display (I forgot which). Ultimately, he got a cash settlement to make up for the additional depreciation of a screwy dashboard.

Your dealer might be more flexible and willing to find a decent settlement, but MB likely won't. If they fixed everything wrong with all of their cars on the road right now, they'd go broke.

Thank you, Joe.
I am not really sure if this engine is sleeved. I keep asking questions, but the answers are quite vague. I was trying to look for this engine schematics, to see what I am dealing with and no avail.

Doesn't carbon buildup mean that the engine is burning oil?
And if it's so severe that the second time around they decided to rebuild the engine, shouldn't have they done it in a first place? [I know, that one is more rhetorical question]

VehiGAZ, I have not spoken to the dealer yet, but I feel like I got cheated a bit. When I was buying this car, they asked me at the desk if I want it certified. It was strange to me at the time but I couldn't understand why it bugs me.
They cashed in extra $800 and waved me goodbye. I was reading yesterday on dealer's site that "Factory Certified" means it goes through rigorous inspection before it's sold. It shouldn't be sold if there is a slight chance of something wrong with it.
Ever since I got it I put in it nothing but top quality gas - as much as you can trust it is top quality. I know how I treat my cars, and I know I wouldn't feed it garbage. Therefore I know it wasn't me mistreating it. You see where I am heading? There is no way that carbon buildup became so severe over the 6 months I had it, that it needs an engine rebuild. Especially that my first visit to the dealer took a bit over five days for them to "fix" it. I was also informed that they run an engine cleaner on a half a tank of gas to make sure things are working fine.

Forgive me. The more I think about it the more upset I get.
This is my daily driver. I drive a lot. Now I don't trust it anymore.
And I am upset with the dealer too. They've had my and my family's business for last 10 years. Very disappointing.

What's the condition of the supercharger of your benz?
I haven't heard much about top end rebuilts over here, but a lot about reconditioning the supercharger.
Rebuilt cilinder heads aren't that expensive as well.
Check out these guys:
http://cgi.benl.ebay.be/Zylinderkopf...QQcmdZViewItem

Carbon build-up is caused by poor quality fuel, and the United States has the poorest quality fuel (gasoling and diesel) on the entire planet. I take that back, Mexico has the worst fuel and we're the second worst.

Here's some info on carbon build-up that BMW was having an issue with on their E-series cars (courtesy BMWCCA):

Quote:

---

Carbon Buildup was a common problem for the E28 535 caused by
poor fuel quality. Many BMW's experienced rough idle due to carbon buildup
while still under warranty. It is recommended you use premium gas at least
once in every 4 fill-ups. The premium gas contains more detergents to remove
the carbon deposits from injectors and gum/varnish buildup on valves. That
said however, some Oil Companies add no additional detergents to their
regular or premium fuel products... Ask your fuel company for information.

BMW North America undertook an engine campaign to pay for the removal of the inlet
exhaust and sand blasting to the back of the valves with crushed Walnut Shells.

---

Note that this issue was exclusive to North American cars, and the rest of the BMW fleet using the same engine had no issues.

In any case, there are some additives that can be used to help reduce build-up. I'm generally not a big propronent of "miracle juice" found at your local parts counter, but have been using LiquiMoly products in my diesels with great success. They have a product called "Ventil Sauber" specifically for carbon valve build-up in gas engines and I've received very positive feedback among various applications. You can sometimes get great pricing on eBay for their products if your local NAPA or auto supplier can't get it for you. LiquiMoly Web Site.

Good luck and just remember some engines are more susceptible to fuel quality than others, even among the same type. Especially vehicles with forced induction since the compression charge is higher.

http://www.mercedes-benz-usa.com/c_class.php

That's all I'll say about mercedes-benz (not Capitalized on purpose).

I think my buddy was one of the posters on that page! Yeah - very poor quality in the C-class. Jeez, I had an early-in-its-first-model-year 1984 190E that was crappy, but not THAT crappy!

Here's something on fuel quality that I came across in Car & Driver recently:

http://www.toptiergas.com/index.html

Thx guys.
I think I will rationalize any sudden moves later.
I will keep my eyes open, but I am leaning towards BMW 330ix more and more...
For now I'll just sit tight and see how it works out. If it doesn't, my little kompressor is gone.