ncmudbug

A friend of mine with a low mileage (40-50K) '06 C230 was having a problem - I believe he had a miss in his #1 cylinder (I'm afraid I can't remember the specifics exactly). I believe the stealer had changed out the coil and cam magnets and he and I changed his spark plugs. He took it to an indy and it looks like he's looking at a $1000 bill. The indy did a compression test (good) and a leakdown test (leaking through valves). His solution was to take the head off and send it to a machine shop to have all the valve springs tested (especially #1 of course) and have the valves checked out. He is expecting that there is carbon buildup on the valves because of a weak spring or because of cheap gas. He hasn't changed his fuel filter, he commonly runs it almost to empty, and he hasn't used Techron yet.

I was skeptical at first, but hearing the indy discuss it, what he is doing does seem to be reasonable to me, but his diagnosis seems a bit out there (on the other hand, I have no idea what could cause it).

I would be really surprised if there was a problem with spring(s). I've never heard of springs failing with low mileage like that in a street car (but stranger things than that have happened - like an A/C compressor being trashed by a failing alternator clutch pulley).

This is what interested me: he implied this was possibly because the Mercedes engines of the time had Mitsubishi parts (at first I thought he meant that they used Mitsubishi engines! but I was incorrect). He said that during their "tryst" with Chrysler, Mercedes used Mitsubishi parts because of Chrysler's relationship with Mitsubishi. Has anybody heard of this sort of thing? Mercedes using Mitsubishi parts??!!

The other cause that was discussed was the fact that my buddy used Sam's Club gas (premium), he hadn't changed his fuel filter yet, he never used Techron, and he commonly drove on empty. This seemed to be a possible cause of a misfiring injector rather than carbon on the valves.

Anybody have any opinions on this...

Glyn M Ruck

The whole Mitsubishi thing is rubbish. The new M276/M278 DI engines were spawned from the Chrysler era development but the Chrysler version of the engine - (Pentastar) is not DI & shares no common parts with the Bad Cannstatt built Benz versions.

If the car fails a leakdown test & it's not rings then the heads must come off to reseat the valves & investigate the leak. A prior boroscope inspection will soon tell you whether there is carbon on the inlet valve tulips.

Glyn M Ruck

Need one of these nice babies.

ncmudbug

Cool scope! Thanks for the comments, Glyn. I was skeptical of the Mitsubishi story, but then I know that Ferraris have Fiat engine parts (stuff like valve shims, etc.) so it seemed possible if unlikely.

Do you think my buddy's fueling habits could have caused this?

Glyn M Ruck

Fuelling might have caused this. But I presume we are talking an M272 V6 here? An engine not known for fouling. However raw non additised US gas is not good. It might be a valve spring but it could also be a burnt valve caused by a gummed up hydraulic lifter. Has this car been properly maintained?

The Daimler Chrysler marriage did not last long enough for a rationalised supply chain to form. (Rather Chrysler use of complete Benz assemblies like the aircon controller in the Crossfire, old ML platform for Jeep, Old E class platform for Chrysler 300C etc.) Especially when it comes to gestation period on a new engine. Almost every part used in the Bad Cannstatt engine plant is either manufactured in house or supplied from a satellite plant JIT in the vicinity.

That said crap Delphi injectors got into the Benz diesel supply chain. But Mitsubishi - No.

EDIT - Going forward we have the Benz Nissan/Renault collaboration in the US due to casting capability & there will be engine components going to Tuscaloosa for US build.

ncmudbug

Yeah, it's a V6. I don't know how well it was maintained - I assume he kept up with the schedule. One thing is that he didn't drive it very much.

I'm leaning toward the lifter but that cheapo gas certainly didn't help things. I'll know more when he gets the car back (assuming his indy is honest - and so far he seems to be).

Thanks again!

LILBENZ230

If it were cheapo gas it doesn't look like it could have materialized this quickly. All the M272s on the forums and you know not everyone is using top tier fuels and yet we have no reports of anything like that. I'm guessing that Glyn is right and it is a lifter or something like that.

Driving till empty shouldn't harm the car. I'm never going to understand that mentality. Why would a car company engineer in a 16.4gal fuel tank knowing the car would be damaged by using more than 13 at any given time. It's just a myth. If that could hurt it my car would have had fuel system problems a long time ago.

ncmudbug

I tend to agree with you, Matt. I think the driving till empty deal - if true - would clog up your fuel filter rather than cause carbon buildup.

I forgot to mention something else my buddy's indy said - he advised changing the fuel filter every two years. That sounded pretty extreme to me.

Glyn M Ruck

Fuel filter should be changed on mileage - maybe every 50K miles.

ncmudbug

That's what I understood. The stealer told me that it was 5 years/50K miles, but unless you think you have a lot of trash in your gas tank, mileage makes more sense - the element doesn't get stale! Either way, I changed me and my buddy will have his changed, too.

I think my buddy's indy is doing the right thing, but he seems to have some strange ideas!

phil240

My guess would be if it sounds like carbon build, does he make alot of short trips in the car or live very close to work. I have seen older people that only drive a car a mile to the store can get pretty bad carbon build up on the valves by not letting the car properly warmup. But that being said its not common to hear that sort of thing on these engines but a really quick store run over and over could do it.

LILBENZ230

My fuel filter was changed at 100k and it was fine. I didn't know it was a 50k mile interval.

That said, it was fine, I didn't notice any improvement after the change.

kluvsbenz

Haven't changed the fuel filter or plugs. At 96k, it is still running like a Deere!! Oops, wrong company Anyway, those 2 things are on my to do list for next month.

nfamous209

change out fuel filter and seafoam see if that will free up any carbon build up as well as clean your fuel system. stuff works wonders.

Glyn M Ruck

Do not on any account add Seafoam to the engine oil. While the car in question is obviously out of warranty - Benz will nullify warranty if you use it in the gas as well. We had a recent case of this on another forum.

ncmudbug

I know this thread is stale but my buddy finally got his car back from his indy. It turns out that it wasn't the valve or a mechanical part - it was his wire harness. I don't know a whole lot more than that about it except that the indy did not get any answers from MB (appeared to be clueless about the problem) and he also appears to be a pretty good indy. He either didn't charge for the head work or he charged much less than it would normally cost (haven't seen the receipt yet). He considered it education. It still wasn't cheap - I think my buddy said it was something like $1300 in the end.

I'll know more later. He may even call him to have me talk to him.

Glyn M Ruck

Very interesting. Tell us more when you know.