Open letter to Larry Bible- Help me with my V12, no one seems to know anything about.
 

Dear Mr. Bible,( and all others reading this )

sorry to trouble you, but I have a technical question for you. You seem to be quite knowledgeable, so I am seeking your insight here.

I have a 1993 600SEL sedan with 84k miles on it. The car is in great cosmetical shape, it was garaged and has been dealer maintained by Plaza up in St. Louis. I'm a small one man operator who buys, repairs (light repair work), and sells old Mercedes on ebay for a living in Memphis,Tn.

Anyway, I bought this 600SEL at a local auction, and the only reason I bought it was due to its stunning overall cosmetic condition. I tested the car at the auction and it ran great, smooth idle, and no check engine light.

After I bought the car @ auction, I noticed it was smoking after running for about 30-40 minutes on the highway. Later it stopped smoking as abruptly as it started. The smoke was whitish/blueish and was very acrid and potent. Made your eyes sort of burn.

I continued to drive the car and it continued to intermittantly smoke. The smoking never occured when cold (which is why it appeared fine at the auction). The smoking did set a check engine light, which revealed the following-

009- Transmission overload protection switch DI2

013 -CMP- sensor signal DM

034- O2s DM

017- Can-data exchange DM

ADS-

008 - Solenoid valve RA Y53Y1

009 - solenoid valve Y53Y2

Group LH1

008 - CMP sensor signal L5/3 Not recognized

Group LH2 SFI

02102SG3\3 - Signal Open Circuit

022- o2s Heater G3\3 02 heater open circuit

The smoking would start after 30 minutes or so, and then would subside if the car was left to idle. I pulled all of the spark plugs and noticed they were perfect! I checked the crankcase oil and it was VERY clean and showed no signs of contamination. I checked the coolant reservoir and it also showed no signs of contamination.

The next time the car acted up, I pulled over and I rasied the hood while the car was running. I looked at the engine quite a bit and I noticed that while the car was running that one of the vaccum lines had fluid in it.
The clear / Red stripe vaccum line running to the ignition control module on the driver's inner fender had oily fluid "pulsing" through the line towards the ingnition control module. I traced the line back to the intake and it was connected to the right intake manifold (passenger side). I then carefully removed the intake manifold(s) and found what I believe to be clean crankcase oil pooled in the intake wells. Most prominently in the right side of the intake. It looks like oil from the crankcase, but I suppose it could also be hyraulic fluid, but my guess is oil.

Something is contaminating my intake and then being atomized and burned. The car is smoking like a freight train when it is burning whatever is in my intake.

I read the MB model year update and looked at the sections regarding M120 crankase ventilation , and looked at the oil seperator and the dampner, but they didn't have any traces of oil in them. I have been suspicious that the seperator was failing, but see no signs of oil pooling anywhere in the circuit.

The EGR on the right side was all gummed up and looked like it was clogged with caked oil. I cleaned the passage which was nearly fully obstructed.

I have a copy of WIS on my computer , but found nothing of note regarding the M120.

I also noted that there was an aftermarket muffler shop type CAT on the left side of the engine that had been welded on.

Do you, (or anyone else reading this) have any ideas for me?


Kind Regards,

Herbert Phillips (Herbert on Ebay)
800-310-8767

Most cars sold on auction lots are generally a POS. That's why they went to auction.

The smoke sounds(or perhaps smells like oil) and it may be why a few of the codes are being thrown, but across the board, it sounds like you bought a genuine problem.

Good luck.

You may want to check the vacum modulator at the transmission. It may be letting fluid up into the intake and causing your smoking. Just pull the vacum line where it connects to the transmission and see if transmission fluid is there. If so replace the modulator.

Here's a wild guess - does the car have hydraulic lifters that are shot? Sorry to hear about you bad luck. Any recourse on the auction house?

My engine is half the size of yours (3.2L) but I had a simular problem, lots of codes, the foul smelling smoke was fuel, she was running rich. Checked injecters, slide actuator, replaced wiring harness, air mass sensor, & O2 sensor. Turned out to be the engine control module (ECM) This problem is becoming more popular as the ECMs are getting older. The ECM sends false codes and shuts down some cylinders. I hope this is not your problem.

Aside from the vac modulator at trans [ techman post], I have seen a bad rear master cylinder seal fill the brake booster with fluid . It gets sucked right into the intake and smokes out the exhaust.
Rare, but worth looking at. usually have to keep adding brake fliud, but you do not know that cuz ya just bought it.
Tranny mod is usually red , but also a good possible.
Take a peek at the rear res levelon brake system and if it is down, take the hose of and see if it is dry..

I am not familiar with the V12 cars, but as Arthur and others indicate, this seems to be a foreign fluid ingestion.

It sound like the engine is receiving a foreign fluid through a vac line somewhere. Whatever it is it's been happening for a long time because it plugged up a catalytic converter. Since only one converter has been replaced, I would try to isolate every vacuum line that draws vacuum on that bank.

Once you've found the problem you will probably have to replace the cats.

Good luck and keep us posted. This one will require patience and dilligence. I do believe that the source of the problem will be something relatively simple and inexpensive once you find it. After the fluid source is found and fixed, write down all your codes and clear them then go from there. You may have a few other gremlins to chase out.

Good luck,

V12 - White Smoke
 

Well, this is my first post, although i've been using this GREAT N WONDERFUL site for 1.5 yrs. Since many senior tech'ies are always around to answer, I never got the courage to post reply ( fearing i may sound like a dumb fool).

On this particular issue of White Smoke in 1993 S600 (or 600 SEL) V-12 Chassis W140057, Engine 120980, i think i can shed some light since i went through the same pain/ordeal as HerbPhillips. Only difference being that my intake is contaminated from black sooty oil (rather than clean crankcase oil as Herb suggested), probably coming from PCV inlets at bottom of EA/CC/ISC throttle actuators.

Herb - DON'T THROW PARTS AT IT YET !!. You need to do a few things as listed below :

1. Check your Air Mass Sensor (MAF) wiring harness. I'm sure it has lost insulation. Replace MAF wiring harness upto the computer box (very important).
2. If wiring has lost insulation, u may need to replace the MAF sensors also, as these go bad due to shorts in wiring. Make sure that rubber hoses that connect MAF to intake manifold thru EA/CC/ISC actuators are not cracked.
3. Check that two purge control valves of EVAP system are functioning properly - heartbeat effect while engine is hot. Check the charcoal canister line for clogging (carbon deposits).
:rolleyes: above were major source of white smoke for me.

4. Check all Vacuum lines for cracks, clogging/blocks. Clean/replace as neccessary (Very important). Vacuum lines towards the windshield are difficult to check.
5. Check that all vacuum/suction points of Intake manifold are open (not clogged at the intake manifold itself).
6. Clean, as far as possible, black pipes/lines that run over the engine for Positive Crankcase Ventilation system.
7. Clean distributor cap, and other ignition contacts (i presume ignition componets are working fine) - check that all 12 spark plugs are firing.
8. Check key sensors - Two engine coolant temperature sensors (ECT), Two Intake Air Temperature sensors - for proper resistance rating.
9. Replace air filters, engine oil/filter, tranny oil/filter etc.

Have patience, there are 'n' number of things still to check - CATs, O2 sensors etc. Don't jump to conclusions immediately after doing all of the above. Run the car in various driving conditions for 300-500 miles and see your white smoke problem go away.

If the car was sitting in the Garage for some time, I would also recommend to take out all the modules (ICU's) from computer box and clean all/EARTHing contacts (module connection brackets, side contacts on module box etc.). Clean other electrical contacts as much as you can.

This car has attitude, if you respond with care, it will correct itself.

Keep us posted. This problem can be solved and will be solved.

Problem still isn't fixed..
 

I let one of my mb mechanic friends talk me into letting him take the heads off. He was convinced that I had worn valve stem seals....

Well the machinist said the heads were beautiful and that the seals were fine, but I replaced them anyway..While I was there, new motor mounts, and new plugs, wires, (ouch!)...Still smokes like a pig after about 30 minutes.... Guess I threw parts (and time and $$) at something...Anyway, still scratching my head... Any additional ideas?

After smoking, I can shut the car down, let it sit 30 minutes, and then it idles runs/without smoke.

I checked the cats to see if they were causing pressure in the crankcase via backpressure, and they weren't...(zero backpressure at the beginning of the cat).

not helpful.

tom w

ouch! sorry for your impatience. we have all been there too.

the above posts citing the tranny modualtor and the possibility of brake fluid seem on the right track to me. also the bare wire. i have never smelt brake fluid burining in an engine but i bet it would stink!

tom w

Herb, I work at Plaza, in the collision center...if all else fails, there are 2 good tech's in service who I would trust to chase an odd-ball problem like yours. To be fair, though, very few V12's were sold and most MB techs really don't know that much about them.

I think ATF getting into engine through the vacuum modulator would give out a dark smoke, not a whiteish/blueish one.

Did you have a leak-down test done on the short block while the heads where off.?
Assenmacher sells a tool I use, that bolts to the block over the bore and lets you use your leak-down tester run a pressure/leak test on each pot.
Any pot leaking over 15% is candidate for rings or at least, further investigation.

Good reading is 2% to 12%.

ATF will white smoke, like a lot of steam, but hangs around longer.
.

Thanks for the info...:)

Thank you for the responses.
 

I'm still scratching my head on this one.

The transmission fluid contamination seems plausible, and I did have a trans fault code when I had the car scanned @ MB.

I had my tech check the vaccum line last year when the problem 1st surfaced and he reported that it was "bone dry"; but perhaps it just sucks it clean, and leaves no traces?

Can anyone identify the vaccum line and its location?

I'm thinking I may use a temporary block on the line and see if the contamination problem subsides.

Still working on it, but I'm driving it now, so I'm more in-tune with the car.

I've established a few ideas-

Engine is good; when not smoking it passes local Memphis emissions test -
Yesterday @ the inspection station, vehicle was well below CO and hydrocarbon limits.

After driving 30 minutes, smoke begins, along with a slight misfire accross the board (all cylinders), then oil (or contaminate is burned off and engine runs perfectly again).

Keep in mind, I took both heads off, had them machined, replaced all 48 valve stem seals and every gasket on the top end. Also new plugs, wires, and distributors.

When the car is in a smoking fit, it emits whitish , steamyish smoke that rolls like fog. Smoke is not sweet like antifreeze and coolant level has not changed, car doesn't overheat.

I noticed a wet residue running through the crankcase vent tube @ the left (passenger) valve cover when the car was smoking.

A tech @ the local dealer suggested the check valve on the oil pump being bad and the pressure being too high?

Car has had new throttle actuators and was serviced @ plaza, though the shop forman didn't remember the car and wouldn't help me with any clues...

This is something I've a little experience with as I have dealt with bad vacuum modulators beginning with my first,a '63 Mercury Meteor.

Tranny fluid is almost pure white and very acrid when it burns,that's one clue.
Also dependant upon the inside diameter of the line the smoke will be either greater or less.

Additionally in certain speed ranges and shift positions you will be able to tell when it will happen,while in drive the tranny may have greater pressure thus seeming to make more smoke.

I do not know where the modulator is on your car but the very fact you have fluid in your vacuum lines would incline me to look there first,unfortunately some Mercedes,notably my '98 did away with a tranny dip stick,how about yours?

Ohh,has the brake fluid gone down?

Sure sounds like the engine is sucking in something that's not supposed to be there. Tranny fluid will definitely burn white, and look like fog out the tail pipe depending on how much is being burnt. It is surprising how much moisture rides along with oil vapor in the crankcase ventilation system.

First thing I would try is getting the engine up to temperature and smoking, then remove the oil fill cap (place a rag over the hole if necessary) and see if it makes a differenece. You may have to wait a bit for any moisture in the system to burn out of the exhaust. It should be possible to remove suspect hoses and lines (plugging where necessary) to see if you can isolate where the fluid is coming from.

Just throwing out a wag, but what about a stuck EGR?

My friends M120 had one of the EGR's stick open. Car had a slight miss, and smoked a bit on start up. Smelled like a carb running rich actualy.

Luckly the problem was caught and correct fast, so the cats were not hurt, ouch they are pricey!:eek:

Smoking V-12 mystery
 

I have an identical issue with my 94 sl-600. Haven't found the cause -yet. It DEFINITELY is engine oil 'pooling' in the intake manifold runner. How it gets there is the mystery. I SUSPECT the oil drain-back holes on the head are marginal or? and the PCV system sucks up a little bit somehow. I am gonna modify the PCV inlet with a deflector or ?
Exactly the same symptoms 20-30 min of operation, smoke starts, then will go away. Sometime worse than others. Seems is gets a slug. Engine operation conditions do not seem to make any difference.

I agree with the brake fluid. Although I am not sure about the brake booster setup on those cars.

Fluids
 

....Very typical on older ford and gm vehicles....Leaking Transmission modulator smokes more when you decelerate ...high vacuum....
No doubt its got a drinking problem
Drinking and Driving……
No respect for the law…..
sounds like transmission fluid. Transmission fluid smokes like crazy and you only need a small amount
May be a little experiment here Dr Frankenstein…..
Can you put some transmission fluid in a spray or squeeze bottle..
Rev it up slightly and bottle feed it with a quick squirt…..
You should get the same effect….SMOKE
Does it look and smell the same....??
Don’t try it with brake fluid!!
You can however remove the master cylinder and look behind the master and look into the booster.
Is it wet???

Try this. http://v12uberalles.com/

Oh, I remember a thread on this problem... There was another V12 with the same problem. It turned out to be a vacuum line leading into the throttle body that was injecting motor oil into the intake. I will see if I can dig up the thread...

It would be GREAT if you could find that thread!!!

As an experiment , I removed the vacuum line from the trans to the intake (@the intake) , drove the car; still smoked after about 30 mins...

Now I'm guessing its either brake fluid , or oil .

Any ideas on what else I could disconnect?

is the white smoke coming out of the exhaust or just out the back of the car?have you considered an overful transmission?when the tranny heats up after driving excess tranny fluid can spill out the vent and hit the exhaust.:confused:

Here's what you really need to do.

#1 Stop tinkering with the car! You probably doing more damage than good!
#2 Locate and talk to someone who has specific Mercedes Benz training on the car. Not just "some guy" that has worked on a couple of them. Make sure they have gone to the factory class! You may even have to go to a dealership to find this person.
#3 Tow the car to their shop
#4 Pay them well for correctly diagnosing your car and repairing it and preventing further damage from people who don't know what they are doing working on it.
#5 Continue to bring the car to them and have them care for it.

You notice all the V12 badges on the inside of your car and how it has a leather dashboard and other things a regular S class does not? Thats a polite hint from Mercedes that this car is not like any of their other cars and is "special" and requires specific knowledge to correctly service and repair. As much as I would love to have a V12 (more really for the interior than anything else) I would want to locate a mechanic that has worked on these cars before I would even consider buying one.

maybe this will help
 

maybe this will help.............
http://www.faqfarm.com/Q/What_can_cause_white_smoke_from_the_exhaust
You need to determin what kind of fluid this is....and go from there..

That's a great idea, except for two things. There was never a "factory class" for the M120 V-12. Also, given the rarity of these cars, finding an MB tech who has worked on more than a handful of them (not just routine service) will be very difficult.

I think you should take a closer look at the crankcase ventilation system. The entire ventilation circuit should be carefully checked. Maybe monitior manifold pressure. Is it different when the problem occurs?

Hmmm
 

Have you made any additional discoveries on this one? It reminds me of a problem I had. An auxillary vacuum pump failed, this caused the engine to suck oil into the intake. It is vacuum related, since it only occurs at warm up and then goes away. Good luck!

Herb, sorry I didn't get back to you. I "misplaced" your pm to me. I re-discovered your thread just this morning. I still think you were on the right track when you suspected your PCV system. If you look at the attached diagrams and descriptions, you can see that there are pathways oil can take to get to the ETA's and then into the combustion chambers. Hose 4b seems very suspect. I would also double check the Damper 7a.

Herb, will have to e-mail the diagrams to you. This Forum's 65KB limit on attachments prevents me from posting them. Check your e-mail later today.

Pete

Gee. I wonder how he found your web page.:D

The thread that I remember was started by you (Herb Phillips). I can still post the link, but I don't know if it is going to be helpful or not.

I've got an SL 600 in the shop with the right side head removed. In the bottom of the valley there's some piping which allows the separated oil to drain back into the crankcase. If it were to become restricted, I could easily see how the engine would run fine for thirty minutes, then begin to smoke. After the engine is shut off, the oil remaining in the pipe drains back (slowly) into the crankcase. The next time the car is driven, it takes about thirty minutes for the oil to build up again, and the process repeats itself. Make sure the drain pipe isn't partially clogged.

Given the smell/pain factor (ie, bad/acrid) I'd lean heavily on the brake fluid being sucked through the master.. A little brake fluid goes a Long way towards making smoke (white) and it smells something awful.

Jonathan

Even if they are hard to find someone who actually know's what they are doing would be better off for the longterm longevity of the car. If I were in the market for a car like this I would locate my repair resources before even buying the car.

Are you saying that these cars suddenly just started appearing at dealerships with no documentation or training program setup for them? I always doubted the abilities of stealealership based service shops because of the way they go through people but now I'm really horrified. When a customer comes in for repairs they just guess at what to do?

You mean, some shops actually don't understand what they are doing ??


.

Any word on what was allowing the oil in the vac lines?I discoverd some fluid in the vac line going to the ignition box(ezl)on my 92' 600sel.The car does not appear to be burning anything it shouldnt(no smoke)and runs well,but I sure would like to find out where this fluid is comming from and cure it!!Thanks guys.

honestly I cannot quantify what fixed it. Here's what I did.

removed both heads, had them cleaned/machined.
new head set, new head gaskets
replaced all seals on the intake and all 48 valve stem seals
replaced a bad mass air flow sensor and the harness going to it
replaced a bad oxygen sensor
forced the throttle actuators to re-learn their positions.

One or all of the above cured the problem, but whew! ...the M120 is serious business, not for the meek or faint of heart.

After this, my 6.3 seems like childs play.

Herb, I'm glad to hear the good news for you. You're right about "... not for the meek or faint of heart". Could you tell us how much the above fixes cost you? Maybe it is a motivation for me not to look for a V12 :), it's a nice car to look at though. Such cars are driven by some head-of-states in the world.

I'm not familiar with many abbreviations like POS, is it Previous Owner's Sh..?

POS=Peice of ****

Some might call it a piece of ****.

The V12 is a whole different machine, and its true that they are not for the faint of heart. Everything, from the suspension to the gearbox was reworked for these awesome machines.


Yes, they may be expensive (a rebuild for the M120 V12 at my indy mech. would cost over 3 grand, and that sensor for the ADS that comes standard on the V12 models may cost over 500 bucks), but I would get another one in a heart beat. That growl, that pull, and those insanely beautiful V12 badges make it simply irresistable!

GANG!!! NO matter how it's spelled, you are in DEEP ****, whenever one of these V12's begins acting-up. Trying to analize the symptoms has to be a life-altering experience!

I want a V12, in the worst way. There is no one in my neck of the woods, that I know of, or that I can afford, to help me, keep one healthy. :behead:

You guys that own one and are happily motoring, BRAVERICHARD, Where are you? My compliments and admiration. :pleased:

$3k won't rebuild an M120, $3k might be enough to pay someone to take it apart.:D Add a zero....

Hattie, a MB M120 crate motor from the fatherland is around $26k.....



I was bored and at the dealer, and they pulled that out of the computer.

Yep so $30k to have it installed.:D If a crate motor is $26k, a long block is probably what? $18k-$20k? Figure a good rebuild is probably 70% of that.

The reason I am saying this is because a proper rebuild on a 617 runs about $3k if you watch your money, and thats just a little 5cy diesel. A set of cam's for the M120 must be like $2k.:D

Thanks for the reply Herb.Reason I was asking I noticed some fluid in the same vac line on my 92'.I am not seeing any signs of smoke out the back but that being said I would like to catch the problem before that happens.