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.

__________________
'91 300-SEL

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?

__________________
dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

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,

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).
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.

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

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

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

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

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.

__________________
2002 Ford ZX2
2 x 2013 Honda Civics

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

__________________
Current Benzes

1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"

Res non semper sunt quae esse videntur

My Gallery

Not in this weather!

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.
.

__________________
[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Thanks for the info...

__________________
Current Benzes

1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"

Res non semper sunt quae esse videntur

My Gallery

Not in this weather!