C230 Sport Coup

Wow, great deal on the plugs! Yes, I DO have issues with connectors. Wondering and hoping Mercedes has a repair kit for said
connectors (wiring harness side). I'm missing most of clips, just stuff the connectors in. A couple times they fell out.
But easy fix, pushed them back in. Car runs like crap on 3 cylinders. You need a metric allen to get the cover off but the right size screwdriver will
do . All my experimenting with different spark plugs has taken its toll. Yes, absolutely get the MAF cleaner.
Regarding reliability, yes, it can be a PIA. Things that break on this car aren't generally the major assemblies.
722.6 tranny is pretty bulletproof as long as you service it regularly. Engine is solid except for #4 cylinder leak
which for me, I just keep adding coolant No problems with diff or anything like that. I've hit curbs at speed, and
bent the rims even but no damage to the frame or suspension. So solid.
But other stuff like the shifter, EIS (crossing my fingers on that one! So far OK.), are a real PIA.
Stock up on parts at picknpull if you can when a C230 coupe shows up.
Alternators, starters, water pump, fuel pump, are normal failures for any car. For me ~140k for each 1st time around.
Less the 2nd time. Water pump AND fuel pump both at 200K. I did all this work myself.
Also replaced the supercharger a couple times. Not that it seized (though I thought it had but it was the alternator tthat seized, a rebuild of the original)
but just that it's a repair you can't really do if you in some other places. Their lifespan varies widely. I found one with 75K on car-parts.com for $250
most recently from an SLK. Changed the oil, installed along with alternator, new pullies and belts. And the starter failed shortly after.
I pulled my hair out being in California. You can't register the car with any CEL's, and if you drive it more than 6 months without
registration, it can be impounded! Every time you clear the CEL's it resets the readiness indicators. And to clear thme you must drive the car!
Always sweating bullets with the damn 'rediness indicators'. Put a new Cat in and STILL drove 2000 miles and it would not
turn to OK!!! Also secondary air injection. I always warmed the car up till the valve opened on the supercharger.
But one time I drove straight off the line cold, with my foot down and the damn thing cleared.
I tried every "drive cycle" available. Finally I could not get it to click over on all of them within 6 months,
I registered in another county where smog wasn't required for a while at a friends house, and then moved to Oregon, NO MORE SMOG CHECKS!
And these cars HATE WATER. Park outside in the rain, your car will hate you and all kinds of problems, most clear up when the car dries out.
I've heard the tail light seals can help to aleviate this. I haven't tried yet, I got as far as privcing them but no ordering them. I have a garage here, so
with 80 inches a year of rain, it's good thing. But sadly for the 1st 2 years it sat outside in need of repairs.
A lot of repairs. If I can get more than 5K miles without something needing repair,
I'll be thrilled. It could be worse. If you have a 7 speed tranny, oh man, fuggetaboutit. They won't even sell you a conductor plate or
tranmission control module, both are coded to the car which has to be done by a dealer. F me! Dealing with that now
on m' lady's ML350. All 4 wheels locked and won't start! Thats another story. You can't even shift it out of park!
It's ALL electronic, nothing outside the transmisson to shift
Regarding EIS there are people now who can swap the important chips from yours to a used one,
so no longer necessary to pay a dealer $1k plus. You definately need a 2nd car to own these cars.

KevinH2000

Truer words were never spoken.

My wife and I own three vehicles. - 2000 Porsche Boxster, 2005 Toyota Highlander, and my C230. With almost 280k miles on it, the Highlander is rarely out of action. The Boxster is less reliable, but not too bad. We all know about the Mercedes. My collection has allowed me to keep at least two cars on the road at any one time with one very brief exception.

On several occasions, my C230 has sat for a week or more while I worked on a problem or project. Having a third car allows me to work at my own pace and save money by buying parts online.

TheRotaryFox

Do you know if the manual 6 speed transmission is bulletproof? I'm worried about doing a fluid change myself, and since I need to get the clutch changed might as well have a shop do both + diff fluid.

My car is slowly creeping up to 140k so I gotta stay vigilant about all these problems now, other than the water pump.

I've had to park outside during the rain, and car electronics have never been funky even in the recent storms. And since I'm planning on going to university in Arizona, rain won't be an issue anymore. But the heat will (Any ideas on how the coupe reacts to hotter temperatures?)

Hopefully, I never have to change the EIS

112233

The manual gearbox is tough but not well synchronized in 1st and 2nd gear and the shift cable needs to be precisely adjusted. And depending on the production number needs different amount of fluid (less than dripping out of the filling hole, 1.2 or 1.5l). The clutch change can be very expensive depending if the two-mass flywheel needs to changed (very likely at 140k mi). In Germany the flywheel is 1000€ alone, which is insane. So be aware which shop you choose to do the work.
And, yes, you need a 2nd car to have time for DIY repair of the old Mercedes Right now I drive since Jan with a broken spring, had no time and very bad weather.

BTW: In Germany, there is a silent recall for rusting through rear axles. You can go to the dealer and inspect the rear axle and they replace it for no charge if it has rust inside.

TheRotaryFox

This clutch change is gonna empty my pockets.

Do you think the US dealers will inspect and replace the rear axle for free?

C230 Sport Coup

I don't know about the clutch, I have auto and glad I do. This was the 1st car I owned with an auto,
I drove both at the dealer, but after years of sitting in traffic, and driving the 5 speed tiptronic auto, clicking through the gears,
yeah, no contest. And it's so durable. You do get 20 extra HP to the wheels though with the manny.
Regarding heat, the only thing is the MFD in the dash. Becomes invisible when you hot but if
you look around you should be able to find a replacement. I got one in a group buy eons ago.
Easy to replace. Cut up a coat hanger, push 2 pieces of wire into the 2 holes on the side of the
speedo/dash module, push 'em in, pull module out. Connector has a slide piece, just slide it, and connector will pop out.
I can't remember if it throws a code though.

TheRotaryFox

Took the coupe out on some backroads with friends.
She performed flawlessly other than the blown shocks making the car bouncy lol

Here are some pics:

My friend's 2021 M440i and my coupey


BMW looks like -00-


Sienna is the best car here lol

TheRotaryFox

Out of all the cars I've driven, the manual ones are the most fun, and they aren't that bad in traffic.
Maybe that will change when I'm older?
Isn't the manual a tiny bit quicker than the auto?
And since the manny has 6 gears rather than 5, I've heard it gets a little bit better MPG.

If the only issue in the heat is the MFD, maybe I can just postpone it.
I'd prefer actual gauges than having to fiddle around the MFD to look for my engine temp and having it reset my position because of the bulb-out errors.

BF_JC230

Heat - get a fitted car sun shade for the front window, we (my family) use aftermarket silver foil foam board ones. It has to keep the interior 20 to 30 degrees cooler when cracked windows are down.

I also have, and leave installed all summer the OEM rear window fitted sun blinds/screens.

You can install a interior motion sensor, like a few of us have done, if you want to leave the windows more/all the way down!

Rain - you can program with Developer Mode, maybe a dealer/regular DAS to use the front rain sensor to roll up the windows in rain.

Down Pours / if I know it’ll be outside for a while in medium to heavy rain, I have a black thin magnet sheet I rounded the corners on, and put over sunroof - works great! Make sure your front (driver SAM) corner especially and trunk drains are clear. There are too many connections in the tunnels and bottom of trunk that do not want water!

Clutch. I have a manual too. Keep this area posted on info. I love it.

Interested on rear axle rust - especially being in USA NE. Bad enough subframes are rotting out - axles too?!

C230 Sport Coup

I bought my car in San Diego brand spanking new, and drive it back all the way on highway 1 along the coast.
Coming up through Big Sur I hit an off camber corner and saw my life pass before me, bouncy bouncy!
Also, I was commuting over a mountain pass once home in the Bay Area California, and fighting to stay in the seat.
So, not even a few months after purchase I replaced the suspension.
1st with Vogtland springs, AMG sways and stock shocks. Shaved 5 minutes off my commute and sailed through turns.
Then at around 80K with coilovers with adjustable shocks. I also learned that to rid the car of oversteer I needed a thicker rear sway,
which I got, and was soooo nice then. I got the stickiest tires I could get and it was riding on rails.
They're pretty well shot now, but still handles well though rough on bumps.
And I don't push it anymore, Khomo all seasons no more summer tires, but doesn't seem to suffer in any way from being driven hard and fast for many years. But she's an old girl now, and I respect that, but still peppy.

TheRotaryFox

I took a slight turn at 100ish mph (Closed course, professional driver )and everyone in the car was sliding around lol.
My friends in the back didn't have their seatbelts on and slid into each other, while I almost fell out of the seat because of the body roll.
And whenever I take a right turn at an intersection a little too fast I'm fighting to make sure I don't fall out of my seat.
My stock suspension and shocks have taken a good beating over the years, and they are well past their due date.
I've been thinking of getting a Bilstein coilover kit as well as H&R sways, but it looks like I'll be leaving my coupe in California when I go off to college.
My driving always switches between full-on redlining racecar or granny shifting at like 10% throttle, and either way the car puts a big smile on my face.

KevinH2000

Consider replacing your stock seats with a set of seats from a C63 AMG. C63 seat swap. This link shows how I did it in a sedan. You will need seats from a C63 coupe, but the general process should be the same. The AMG seats have deep side bolsters that hold you firmly in place.

I recommend that you check out the improved performance of your new seats on a track.

TheRotaryFox

I saw your seat swap thread a long while back when I used to lurk on this forum, and loved the idea.
Doing that seat swap seems like a lot of work and might not be a very smart idea for me since I am planning on taking the car to Arizona for a couple of years (I do not want swamp butt lol).
The issue is my blown shocks and worn suspension components, and I've been looking at a Bilstein suspension kit to try and fix all of that, along with a set of H&R sways.

But before all of that, it seems like my starter is starting to stick just a tiny bit, so it might be time to get some good maintenance done.
I'm planning to do:
Brake fluid flush - Brakes are not as responsive as they should be
Power steering fluid flush - Pump is whining
Diff fluid - Preventative
Fuel pump - Preventative
Fuel filter - Preventative
Spark plugs - Preventative
Starter - Starting to stick a little
Alternator - Preventative

Everything here is the same as it was when it rolled off the showroom floor, so is there anything else I should do while I'm at it?

C230 Sport Coup

Remind me , how many miles on your coupey?
Yeah, if the starter is sticking, that would be my #1, but
in your case you can always push start.
I just went through that, kept thinking, I really need to replace that.
I was still running the original starter, or rather the original starter that had the brushes replaced at
around 140K. That's all I had done to it, $10! And at 252K it died for good, in a drive thru.
It had been making noises for some time, I think I should have greased it up better when
I replaced the brushes after taking it apart and cleaning it. Material from the brushes was packed in there tight.
Starter was Denso, but branded Magnetti Marreli. Seriously!
I always said, Mercedes makes the best Italian cars in all of Europe.
Fix it again Deiter. New starter is Valeo. Got a great deal on it for like $100. Made in Poland.

Smart move on preventative on the Alternator. You can probably get away with just replacing the brushes. The voltage regulator and diodes are likely better quality than what you'll get in a rebuilt. I bought a new Valeo for mine last year about $230 from eeuroparts.com. I had to original rebuilt the 1st time but the diode bridge went out almost right away.
Had to pull and get warrranty repair on it. Should have just done the brushes. You will either have Bosch or Valeo. Best to replace with whichever it came with. I recall people saying way back when that they had fitment issues switching one to the other, but I can't find a single thread on the issue.
I wouldn't bother with the fuel pump yet.
You can probably go to 180-200K on that. I got to 200K.

How did the clutch repair go?
What was the final bill?
Why would you leave your car in Cali, instead of taking it to Arizona with you?
Do you have a sunroof that still functions? If so you'll want to service it.
I posted docs on that like 15 years ago. No kidding.

TheRotaryFox

I got around 139k miles now.
I still haven't done the clutch replacement. It's something I gotta do in July since we are vacationing all of June and up till then I have a lot of finals to prepare for.
Once I do get it done, I'll keep you posted on the bill.

Leaving the coupe in Cali would be a lot cheaper since adding AZ insurance to the current plan will be a bit expensive.
Luckily as a student, I won't need a new license or new registration.
The $800 cost for parking per year is pretty expensive, and considering the university is in the middle of a city it isn't gonna be easy to find a cheaper alternative.
Doing repairs will be a bit difficult since I won't have a garage unless I can borrow a local shop.
Getting it tinted is going to cost a pretty penny, and doing a moleskin install is something I'm a little lazy to do :P
The biggest thing is taking it on the 11 - 12 hour drive from here to AZ, which will be a little nerve-racking since it would be the first long road trip it's had since 2008 .
Back then, we did a family road trip in the coupe 18 hours to Colorado once.

The coupe has a hardtop, so no need to worry about any of those sunroof failures.
I saw the long documentation that you have posted about it and downloaded the pano files just in case I ever meet somebody who needs it.
Every time I wish I had it, I just look at that long thread of issues. Saving myself a lot of money and weight without it

I've met a couple of people who are in the MB of AZ group who are going to the same uni as me, so I should be in good hands if anything happens there.

C230 Sport Coup

So, you have a car to drive there? Or you are going 'carless' (GASP!).
Why on earth would you need to add AZ insurance if the vehicle is registered in Cali?
Fuggetaboutit!
And BTW- Despite all the cute Gieco commercials, "i just saved a bundle on my car insurance" BS,
I just changed to Progressive which in the past was not a good deal, but I have both cars on
there now and was even able to add a small amout of collision insurance, and comp on both cars
for ~300 per 6 months and even less since I paid it in one payment. Gieco raised my rate
over and over again, and was getting $625 every 6 months for liability only. That was it for me.
And this with me being 'old' now, not commuting, and living in a Oregon beach town vs.
insane crazy *** suckass San Jose and it only went UP.
Sunroof was great while it lasted. I had mine completely replaced under warranty once,
and did the washer thing for a while, but eventually it froze and after being barely able to
get it to close it, I disconnected the motor. But it went for I dunno, at least 15 years.

TheRotaryFox

I might be going carless sadly, but I'm gonna convince my parents to let me take it with me since it would be a bigger hassle taking care of it without me.
Not sure about the insurance part so I'd have to get my dad to talk with our representative to see what they say.
Our insurance is Farmers, and I'm pretty sure our rate for the coupe is $100 a month which is good considering it's covering a teen driver and my dad.

TheRotaryFox

Well, I had to top up the coolant for the second time this month.
This is worrying, since there is no puddle under the car.
This leads me to believe that coolant is leaking into the combustion chamber.
Oil doesn't look like mayo.
This might lead to a summer project to replace the head gasket.
Any tips on properly diagnosing this, or proceeding with a head gasket replacement?

112233

Take a look at the back off the engine, most M111 head gasket failure is a coolant leak above the bell housing.
And, the early radiator hoses had aluminum connectors which corrode, if you find greenish stuff around the connectors, they leak when hot.

KevinH2000

This video shows work on an M111 engine in which the coolant was mixing with oil.
If you do have coolant/oil intermix, it does not appear that your problem has persisted as long as the situation shown in the video.

I don't have an M111 engine in my car. I defer to 112233 regarding the specific cooling system problems on the M111. One component that I suggest adding to his list is to check the oil cooler. In some cars, a defective oil cooler can allow oil to mix with coolant. I don't know whether that is a problem in the M111, but it is probably worth checking before you replace a head gasket.

In general, I suggest that you pressure test the cooling system before you conclude the problem is due to a defective head gasket. This video shows the process for pressure testing the coolant system on my variant of the C230. (I couldn't find a video for the M111 with a quick search.) The M271's have 3 plastic coolant pipes that are prone to failure after about 150,000 miles. I've had to replace all 3 of mine. The M111 is likely to have different issues, but a pressure test should point you in the right direction.

Good luck.

TheRotaryFox

@112233 - When I get back home I'll look behind the engine and see if there's any coolant behind the engine or on the bell housing.

@KevinH2000 My coolant doesn't look anything like in the video, but that seems to also have rust and debris in it.
I'll have to see if I can search the forum or look through the WIS to find out how to pressure test the coolant system for the M111.

I was told my car was misfiring, but it's been like this for as long as I can remember.
Here is a cold start in 63 F weather.
Could someone please confirm?

This sucks.

112233

Maybe it is better to open a new thread, with this. Exhaust noise is not to analyze, because on the Coupe the muffer has the tendency to rust through on top of it and it sounds like that. (And on cold start you have the SAI active to alter the sound also)
For misfire lay your hand on the engine at idle, it must be smooth, you almost can put a coin on the M111.

TheRotaryFox

Maybe I should make a thread just for my coupe because it's like Pandora's box.
Open up one thing and go down the rabbit hole of basically rebuilding it.

C230 Sport Coup

Yup. Replace alternator and supercharger, then starter goes out. Replace starter to discover leaking trans pan from 15K mile ago service.
Guess I didn't torque properly, so....trans service. Actually is better now since my fluid level was never quite right, and shifting is much better now.
Big rattling noise in back, Replace rear shock bushings (special from TIEN), and discover my nearly new Sumitomo tires have tread seperation ON THE INSIDE ALL THE WAY AROUND (lucky I saw it!) and no dealers around so warranty is useless. Never again Sumi. Replace tires Khumo, discover front brakes are shot, but I'd had spare pads and rotors sitting on a shelf for 10 years so no biggie,
Akebono ceramics last FOREVER. 170K + miles in C32 brakes. Wasn't sure if the car would last long enough to need replacement. It has.
Do brakes and repack bearings, and shifter starts sticking (was a replacement from Picknpull so not new)
selenoid sticking going from park to drive and vs. versa. OK, don't want to get stuck but lucky me, I have another spare waiting in the wings from picknpull and with a nicer shift knob and boot. OK, did that. So now on shifter #3. Tired of looking at and feeling F'd up steering wheel, so I pull and drop it off at a shoe repair shop (actually I had a spare also from Picknpull $10!) who did a bang up job matching the color and refinishing it, but then discover my iCarsoft scanner won't clear the SRS error from removing the airbag. $150 piece of crap. Nobody around here to clear it. Today I couldn't get the drivers door to open, the pin got caught in the door panel. Had to climb in from the passenger side, and futz with it. Couldn't even open from the inside! My tail lighs randomly switch to alternates, on one side, swapping light modules, bulbs and pigtail connectors does nothing, but most recently just fixes itself. Who knows.
And of I course I live with the leaking coolant on #4 cylinder, but just keep filling it and driving it for 100K miles now. Who need an F'ing car payment these days. I don't have 50 grand for new car, and I don't need someone elses used problem, that requires full coverage and a payment + maybe more problems than the car I might purchase to replace it. Nothing is guaranteed. All this in the last year. I'd write a book for everything Ive done on this car. But no trans issues with regular service, no bearing failures, basic structure is good. And so far the engine hasn't failed catstrophically. amazingly. It still runs and drive great...for now. And so I drive it. Premium is getting damn expensive though.
I'm literally turning into an old man who just drives to the store and back, and still burning a tank every week or so at $75-$100 per.
But I am jonesin to get that 300Kilometer award from Mercedes. After that...who knows. Im curious how long it can keep going. Drive it til it just dies. Our sweet little 'Carly' LOL. She's a good girl. And I can't afford a new benz, and nothing else drives like one.

TheRotaryFox

If you did write a book on everything you've done then I'd buy it in a heartbeat.
Too many unknowns for a beginner like me.

I can't believe I've been blind to the misfire I've had for a couple of years now.
Might go ahead and buy some new coil packs while I'm at it.

I'm driving around with that head gasket leak, but it's dumping coolant into the combustion chamber.
With that goofy MFD I can't even see if I'm about to overheat so I've been driving slowly and shifting at 2.5k RPMs just to be cautious.
I plan to try and live with this leak until the end of the month, then take the engine apart during the summer.

I want to get that 155k mile award from benz at the very least.

This car is a giant money pit, but that's its only downside.
Love everything about it otherwise.
This weekend is gonna be a busy one.
I'm planning on doing fuel filter, spark plugs, power steering fluid, and brake fluid.
Add to that an oil change for my mom's Audi.