TheRotaryFox

Well, right after I said my coupe was reliable the damn thing killed itself.
She still runs and drives, but the head gasket seems to have disintegrated and throws a lot of coolant into the engine.
Lots of white smoke when the revs go high.

I was doing my spark plugs yesterday and halfway through I backed off and threw the old plugs back in.




140kish miles on these
They look beat

But what worried me were the wet valve cover gaskets (I'm guessing here, feel free to correct me)



And the cyl 2 spark plug was wet with a little oil.



I think it's time to let the car sit and start getting on taking the motor apart to replace the gaskets, coils, injectors, sparks, alternator, starter, and fuel filter.
Maybe I can even tackle all the motor and transmission mounts, and get the supercharger rebuilt or ported like SeaCoupe used to have.


My friends were even joking about doing an LS swap if the motor was dead.
(A supercharged V8 would go crazy in this little coupe )

This car means a lot to me, and I'd hate to see it leave.
Kind of feels like losing a family member, 22 years is a LONG time.
Worst comes to worst, I'll try parting it out for you guys.

If any of y'all have any tips, tricks, and/or advice feel free to share.
Thanks for reading a kid complain about owning an old car

112233

Plugs do not look bad. To change the gasket on the M111 is not so painful compared to the newer engines. Remove the exhaust manifold together with the head, usually the gasket blows at cyl 4.
I remember you need a long 12pt bit nut for the head bolts. And change the spring inside the camshaft adjuster, sometimes is is related to the rattling noise of it.

TheRotaryFox

It'll be a pain for me since I don't have much experience.
Spring inside the camshaft adjuster?
Isn't the camshaft adjuster a magnet? I've heard those can go bad.

C230 Sport Coup

There are some great videos on Youtube, I've spent hours watching them and trying to put a coherent procedure together.
There's a guy, Patrick, who has a multi part video hours long in total with an M111 non supercharged, but very detailed.
I know myself and every repair I"ve ever done has unintended boo boo's so I don't want miss a step or drop a bolt in the engine. .
Health issues caused me to put the brakes on the project and also since it's running fine now, I figured wtf, I'll leave it alone
and just keep adding coolant.
I'm tempted to leave the manifolds and cams in place, just pop it off, clean it up, slap a gasket in,
and bolt it down with new bolts, because at this stage to do it right would mean replacing the timing chain.
Hiring someone would grealy exceed the value of the vehicle.
The head bolts might be corroded in place from driving for 100K Miles with leaking gasket.
Getting this little metal plug out by the timing tensioner is also apparently can be a bugger
and you have to remove it to get to a head bolt. So many ways for it to go sideways, and lots of folks who did it, only
to lost the timing chain not long after. I'm not sue if this is an interference engine or not.
I had thought it might just be better to swap the engine, but wow, that seems like a huge job,
not sure which would be worse. I have no one to help me, and no Mercedes shop nearby.
If I get it all back together and it doesn't run...

TheRotaryFox

I've seen Patrick's videos and stumbled on his BenzWorld thread.
I also found that old guide you linked in your "Head Gasket in a Bottle" thread.
This will easily drain up my spare funds and summer time.
Luckily my friends are willing to help me.
A lot of things can go wrong, yes, but I hope that nothing does.
But I have no prior experience so we'll see.
The metal plug by the tensioner, if removed incorrectly, can lead to premature failure of the timing chain? Man...
Giving the coupe to a shop would be a hell of a lot easier, but for sure would be too expensive to be worth it.
And then you always have the paranoia that they must've missed something or taken a shortcut.

My 2 options right now are:
1. Keep running the M111 till it finally gives out and seriously dies.
2. Slowly rebuild it at home and risk it giving out.

A crazy swap that me and some friends thought about was throwing the coupe body on a newer M240i with a B58, since their wheelbases are almost the same.
This should stay an idea lmao.

Buying a non-C7 manual M111 coupe with 90k miles that's for sale nearby seems like an easier option lol, but 5k is an insane amount of money to drop for a donor car.
And taking apart a good car seems stupid.

If you were still in Cali maybe we could've helped each other out.
If I do attempt this at home, maybe I can document the process and make a YouTube video and a write-up on it.

C230 Sport Coup

How much for the 90K mile car?
I always figured I do the work in my garage over the winter, but the last year
I've had various health problems after pretty much never having any my whole life, except
the occasional visit to a chiropracter, and it takes up my time and energy. Hope it all gets resolved soon.
Doctors here where I live now suck. You wait months for anything as stupid as seeing
a pediotrist or even getting a tooth pulled.

TheRotaryFox

https://www.carfax.com/vehicle/WDBRN47J02A344647
Here is the carfax link for the 90k mile coupe. It's $8k which seems like quite a bit for being an old unoptioned car from 2002.
I could've sworn it was 5k a couple of days ago.
I wonder if it would be hard to swap it over to the C7 short shifter.

I hope all your health issues get resolved quickly and easily.

an6dk

I tore down my engine in the same year and model you have earlier this year searching for the culprit of a misfire and ended up resurfacing the block and head re seating the valves and lapping new valves and cleaning the head. If you do want to do the head gasket I can send over the relevant manuals from the mercedes WIS program which should help you a lot and I can also let you know the issues I ran into and what tools youll need to get which you might not have. Id say it shouldnt take you over 7 hours total so if you have everything you need before hand. It honestly wasnt that bad compared to a lot of cars. definitely doable for someone who isnt super into cars.

an6dk

also, the gaskets you showed on the top of the head look in good condition, when I tore into mine it was still running ok and there was way more crap in there than that. That being said the pictures you sent would have been of the coilpack cover area and the little ring seals from the top of the head too the valve cover. Those are probably not an issue and they can be replaced on the way to the head gasket for not too much.

TheRotaryFox

What was the culprit of the misfire?
I’ll take you up on your offer of the relevant WIS docs and the rest of your info.
Thank you so much!

112233

I would change the chain only if it is too long, because you need a special riveting tool to close the new chain. I would not take the risk. There are springs inside the camshaft adjuster which go bad and you hear this "typical" chatter noise at 1200 rpm.
https://mb-teilekatalog.info/view_Su...=05&subgrp=030

And, I would try to get a copy of the WIS (workshop manual).

an6dk

Are you talking about the press fit pin on the right side of the engine if youre looking at if from the front? I had a little trouble with that but once you get/make the tool to pull it then it comes out pretty easy. I did the full deal on mine and its still running about 4k miles later. I did break a socket extension in half getting the head bolts out though, at least the star bits dont seem to strip out at all even with me pulling on a six foot breaker bar.

an6dk

I never got the code to clear but it stopped misfiring so id assume the issue was three of the cylinders having almost no compression, heres a google doc link with some notes and a link to a drive folder with the relevant manuals

https://docs.google.com/document/d/1...it?usp=sharing

C230 Sport Coup

Thats awesome, thanks. I don't have WIS but I have the W203 DVD I bought from Mercedes years ago, and I loaded
Microsofts VM "Hyper V" and created a win 7 image to run it since it wouldn't run in Win10.
I found a script online that allow you to load it in Win 10 Home edition.
So I have quite a few of those. The photos leave a lot to be desired. In the time since
I 1st started looking at doing this, and now, a lot of videos have appeared online with people performing
the repair in detail, but one thing I've learned, just because someone makes a video doesn't mean they have a frickin'
clue about what they're doing. You have to be careful.
So, you removed the cams, right? And the intake manifold? How did you go about decking the block?
I mean don't you have to remove it and send the engine to machine shop or something?
I've done head gaskets on 2 cars previous, a Toyota PU 20R engine SOHC and FIAT X19
SOHC. So dual overhead is new to me. I was only 19 when I did the Toyota. I didn't have any experience.
I hung around the service bays asking the mechanics questions and I put every nut and bolt in an envelope
and labeled EVERYTHING. I spent a couple weeks getting it done, and I could barely believe it when it started.

TheRotaryFox

Been a fat minute since I've been here, but I've been vacationing in Norway and India for the past month.
Saw a couple of sportcoupes there.

Well, the Benz has been sitting for a month, and I took it on a quick drive to charge the battery.
I also sadly smacked the mirror on the side of the garage when I was backing the car out, in my jetlagged half asleep state.
Suddenly the MFD started flashing red and showing an oil lamp icon.
And y'all know the deal with the MFD not being visible if it's even warm outside, so I limped the car home keeping RPMs as low as possible.
Any idea why the car started yelling out of the blue?
I guess the head gasket has to be done now.

C230 Sport Coup

What did it say? Low or overfilled? I change my oil every 5K now, some water does get in it seems, but it hasn't gotten
mayo-naissey so far. It did one time say it was overfilled(!) and I changed the oil immediately.
Had to be coolant!
Wouldn't worry about the chain at 140K. In fact I'm rather surprised the Head gasket crapped out
at only 140K. You sure it's the head gasket?
So, you ran the same plugs for 140k miles? Yee gads man! You're lucky you got them out without taking the threads from
the head with them. So I managed to go a few months with no major problems, but now the AC won't blow cold.
It rarely gets above 80F here but head inland and it can be 100F+ easily in summer.
It had no Freon in this winter, and filled so the windows would defog. It worked for a while.
I see Freon detectors on Ebay for ~20 bucks. I wonder if they work? I seem to recall Mercedes says not to use dye or sealant.
So regarding the head, I spoke to a mechanic, I expressed my concern that the head bolts might snap off in the head
after it leaking for 100K miles. He mentioned a device called an ''inductive heater"
to heat up the bolts before you pull them. My engine is an oily mess, nobody around here steam cleans,
and the thing worry about is all the crispy bits that will likely crumble, wire insulation etc when
I do pull the head...eventually. It runs perfect now, so I'm afraid to mess with it. I'll need new hoses etc.
never been replaced...or failed! Knock on wood.
What if I put it all back together and it fails to run? Well the guy that said you could do it in
7 hours....well maybe from some people, but I'll be taking photos,
labelling every part and taking notes along the way, maybe even video the whole thing,
so I don't get halfway through and go...uh what's this for?
So yeah, probably take me a couple weeks including machine shop time IF I ever do it.
I think in my case I SHOULD do the chain, no matter how painful.
Too many stories of people like me, do the gasket at 250K + and then bam, 10K miles later the
chain snaps.
Anyone know if this is an interference or non-interference engine?

TheRotaryFox

It was around 100F here, and so the MFD was useless in displaying anything.
I could maybe just do a premature oil change, and see how bad the old oil is.
All signs seem to point at a head gasket...
Don't know what else could be allowing coolant to be burnt.
The scary part is being an amateur and putting it back together only to have the engine or timing chain fail.
Maybe swapping in an M112K or an M113 seems to be the way to go if that does happen.
Do you think a proper euro shop would be able to do the headgasket?

C230 Sport Coup

Yeah, but they'd probably want $2500 in labor PLUS parts and machine shop time.

TheRotaryFox

Well it's happened, there is officially oil in the coolant.

So now with the help of someone from the Mercedes Benz discord server, I am picking out replacement parts.

I have been told that for head bolts, I should use the ARP 201-4605 for a BMW 2.3L S14, it's what is needed for the M111 and they are reusable, unlike the OEM ones.

For the head gasket, I am trying to get a custom metal one from Stern Garage's M111 Rotrex Conversion Kit.

For the rest of the gaskets, I am planning to go OEM.

Does this sound like a good plan?

Also, should I replace the timing chain tensioner and guides? Maybe even the timing chain itself?

And people are giving me ideas to swap in an Eaton M62 supercharger for more power.

C230 Sport Coup

Not sure I'd swap the Supercharger while doing a major repair.
Get it running 1st, then consider making changes.
It that even possible to put M62 on our vehicles?
I know the earlier ones had that, but were underspun,
whereas the M45 is working closer to capacity, and pretty much full capacity
when you add a pulley. As you are in Cali, I wouldn't mess with it.

I hadn't heard of using BMW bolts. The Mercedes ones are torque to yield.
As I said previously I spoke to a mechanic, I expressed my concern that the head bolts might snap off in the head
after it leaking for 100K miles. He mentioned a device called an ''inductive heater"
to heat up the bolts before you pull them. They're not expensive,
I would just use what Mercedes recommends. No idea of a metal head gasket.
Replace all the hoses and if you have any bad engine mounts, might be a good time to do them.

Your chain is likely fine at 140K. Not like M251, ours has double row chain.
I would want to replace mine now at 258K miles. Too bad I'm not still in Bay Area we could work on
our cars together. But I didn't have a place to work on cars in San Joser.
Order your parts at https://www.mercedesbenzstarparts.com/
That's Stevens Creek Mercedes in Santa Clara at wholesale (and lower!) prices.
Call before you order anything and make sure it's available and lead time.
Retail counter is like 3x whats on the site.