oil in spark plugs 5 & 3

[jc1kz]

I read somewhere in the fourms here, now I can not remember who had the same issue...just want to know what needs to be done.?
I have a '94 C280 w202 (inline six) My car was suffering from the low idle/would die at stops/like the coils were bad...took it to o'rielly's and got the code P0300 (random misfire) so I bought new spark plugs and a torque wrench, and set off to replace the plugs and coils....removed the plactic MAF air intake (the MAF was good and clean but past the MAF the plastic was smuggie/oily and there was a smaller ??? MAF ??? and it was dirty w/oil) There was a bit of oil going down the throtle body also. So removed the cover for the coils and spark plugs and all looks good, then I remove #1 & #2 plugs they were okay (but did need ro be replaced) then I went in to remove #3 and it had oil on the plug and I guess it dripped down into the cylinder.....cleaned what I could and replaced w/new plug, #4 was okay then #5 also had oil, I did the same cleaned and replaced w/new plugs....(didn't replace any coils) I just replaced the MAF and breather plastic and started the car.....A puff of blue smoke came off the engine area, and every thing worked fine no stalling, it idled just fine too....turned it off and replaced every thing back on the way it should go and started it again and took it for a spin.....(about five miles and back) as I parked it and left it to idled it acted fine....but now I wonder what that smaller (MAF ???) was and where did all that oil come from???? and what to do about that.....I didn't see any oil in the area around the coils and spark plugs untill I removed the #3 & #5 plugs....please advise/help

Thank You,
Steve

[vaspen]

you or a mecanic could have (over filled) the pan past the dipstick mark simple and hopefully that was all it was haha
but when i had my gst eclipse i had somthing simmilar then i changed to a aftermarket intake and it stoped
(i placed a breather filter on the overflow line and i figured that was were all my oil was comming from ) not much help but ey i tried i cant realy say too much without seeing the part your talking bt

[Sulaco]

Valve cover gasket is most likely the cause. Common cause for oil on the spark plugs on M104 engines. Cheap, easy fix.

[jc1kz]

Thanks for the responses guys, Unfortunatly, the problem is not fixed, started the car this morning and it is back to the same thing....So on the next clear day I will take it apart again and look at the seals & gaskets as you suggested Sulaco, there wasn't any oil anywhere else not on or around the engine...I like a clean engine and I'm meticules about wiping it down after it cools off and then placing a cover on the Benz....I will go over it again in a couple of days due to I do not have a regular garage, I live in a high rise condominium (28 fl) instead have two assigned parking spaces...so the only way to work on the car is to take it to the top garage floor and in the sun and fresh air I work on it...but it is calling for rain the next two days, so on Friday I'll take a really good look at it again a double check the plugs and the new coils and spray them all with carb spray make sure their all clean and reinstall and try again....Does the IAT ever go bad? how important is this? By the way Vaspen, It is a mechanic @ the Pit Pros that I take it to so they can do the oil change, as I can't do it where I live, don't really have the space/area to keep oil vac etc for that type of job...and that oil change was done in May of last year, due to I only drive the Benz on wekends and have only put 9000 since then, I change the oil every 10000 miles and it is always clean. the mechanic has two MB's of is own (that is why I go there instead of the dealer, but it cost the same $93.00) so maybe I'll take to dealer this time around.....

[Mike51809]

Maybe the oil seperator is going bad? Thats the way i can see oil getting in the intake like that

[JRE320]

n/m

[Sulaco]

I did the oil and filter on my 94 C280 every 20,000 to 25,000 miles for the 14 years and 250k miles I drove it. I do the same in my C43, '94 E320, etc. Mobil 1 synthetic ONLY in all my cars. My whole family does it (dad, brother, etc).

[JRE320]

n/m

[Scary-Larry]

I used to change the oil at about 11,000, but now I try to do 7,000. The manual for my 98 C280 says 12,000 miles to the oil change (as long as it's the proper, synthetic, oil).
You mentioned the MAF...

Your random misfires and the smoke sounds like a MAF problem, specifically the mass airflow 'sensor.' It is a part that I break every year because I drive the car fast (for long periods of time).
Let me tell you the symptoms I had that led up to me having to change my Mass Airflow Sensor:

Symptoms at first:
-My ASR light was on (but had nothing to do with the MAF, it had to do with the safety problems with the car and not limiting speed sometimes along with other problems).
-The check engine light was on claiming that the O2 sensor was not working correctly, or was getting a bad reading.
-The car was sometimes too slow or too fast at acceleration. Sometime's on the highway at night when I was driving around it would just kickdown to third gear and take off really quick (sometimes spinning the wheels).
-The car was getting really either really good mileage or really bad mileage (no inbetween).
-One night the acceleration was so unreal that I was able to get up pretty quick on a straightaway...shifted from 4th to 5th at just over 140mph while passing a cop (no ticket, no contest). I knew something was wrong, and I didn't care since I was having so much fun. You see, driving at night takes my mind off of my shitty life.

Later symptoms:
-Still an acceleration problem, but it had grown to taking off from a stop too slow and randomly accelerating rather quickly when stepping on the gas while already driving (above 70mph).
-The engine sounded rough sometimes, and even more towards the end of the MAF sensor's life.
-The check engine light sometimes blinked; the codes recorded many misfires on five of the six cylinders. It also included two O2 sensors and the fuel sensor.
-I changed the plugs, wires, kept the coils since they checked out good. Also changed the fuel pump (it was not a fun job at all), and the fuel filter and air filter.
-After that it drove just as rough and got worse....

The final symptoms (on top of the others):
-(White) smoke from exhaust (for the most part only on cold start and shortly after).
-Really rough engine sound.
-Would not go above 30-40mph.
-I went down a hill going the top speed of 40 holding the gas down and the car just out of nowhere shifted into like 2nd gear holding on like 6500rmp while spinning the tires so loud and it just put me back in the seat. It was like 11:30pm and I was really tired, until it happened.

I gave in and took it to a sport garage who does like Mercedes, BMW, Porsche, Ferrari... They calmly told me it was the mass airflow sensor, and that they found the broken electronic component to fix the ASR and other safety problems.

By the way, the MAF sensor doesn't just break from driving performance style, it has to do with changing the air filter. I had an after market air filter that got warped into another shape from the large quantity of air the engine needed. It let unfiltered air into the sensor, the sensor got inaccurate readings to the engine... the engine decided to get more gas and air (hence the O2 sensor failure and fuel sensor erros) and it misfired plugs in the result.
That's it. I really hope you don't have anything major wrong with your car man.

Please don't go down the road I went down (in life) and change all the parts like the fuel pump and such. See if someone can just plug it into the computer and get a diagnostics reading. Please let us know how you make out, we of course care and hope all goes well.

[Sulaco]

They will check your OBDII codes for free at Auto Zone, Oreilly, Advance Auto parts, etc. There's a good chance they will argue with you when you tell them it's a 1994. But trust me. It has OBDII and it will hook up and scan completely normally, just like any 1996+ car.

JRE320: I'm my mechanic. Each guy in my family is his own mechanic. Between the millions of miles accrued across the cars we've all owned, (each with 20k miles between oil changes) there have been no engine issues that could be related to not-changing-the-oil-enough. Ironically, the only engine failure we've had that COULD have been related was my sister in her Chrysler 300--which she took to valvoline to get the oil changed at the regular 5k-7k intervals. Oil pump died in it and seized the "legendary" 3.5l V6. Though, we don't believe the failure had anything to do with her oil or oil change intervals. Probably just a shitty oil pump.

Also, I left out the detail about the oil being on the plugs: it had zero effect on the performance of my E320 M104. 3 of the 6 plugs were covered in engine oil from the bad valve cover gasket, but it never misfired or sputtered once. Sounds like you've got both a MAF and a bad valve cover gasket. Change the MAF first!

EDIT: Are you aware of the 1994-1996 M104 wiring harness issue? Is your engine wiring harness factory original? That was a huge, huge problem on all M104 engines and the only fix is to replace the whole harness.

[JRE320]

n/m

[Scary-Larry]

They will check your OBDII codes for free at Auto Zone, Oreilly, Advance Auto parts, etc. There's a good chance they will argue with you when you tell them it's a 1994. But trust me. It has OBDII and it will hook up and scan completely normally, just like any 1996+ car.

JRE320: I'm my mechanic. Each guy in my family is his own mechanic. Between the millions of miles accrued across the cars we've all owned, (each with 20k miles between oil changes) there have been no engine issues that could be related to not-changing-the-oil-enough. Ironically, the only engine failure we've had that COULD have been related was my sister in her Chrysler 300--which she took to valvoline to get the oil changed at the regular 5k-7k intervals. Oil pump died in it and seized the "legendary" 3.5l V6. Though, we don't believe the failure had anything to do with her oil or oil change intervals. Probably just a shitty oil pump.

Also, I left out the detail about the oil being on the plugs: it had zero effect on the performance of my E320 M104. 3 of the 6 plugs were covered in engine oil from the bad valve cover gasket, but it never misfired or sputtered once. Sounds like you've got both a MAF and a bad valve cover gasket. Change the MAF first!

EDIT: Are you aware of the 1994-1996 M104 wiring harness issue? Is your engine wiring harness factory original? That was a huge, huge problem on all M104 engines and the only fix is to replace the whole harness.

Yes, they will check the codes for free and don't let them tell you that it cannot be done on your car for its age. They claim (at the one near my house) that clearing the codes is against the law (probably for emissions reasons).

Unfortunately, unlike a diagnostic, the codes you will get may be the same thing I had which was misfires, O2 sensor, and fuel sensor. It very well could be the wiring harness too though. But if it's the MAF sensor, it will not flat out say it in the OBDII codes that the Auto Zone or Advanced Auto Parts code computers will pick up. I'm not telling you that it absolutely is the MAF sensor that has gone bad, but the idle, misfire, mileage, random cold start smoke, and acceleration problem was the MAF sensor for me twice. I was only able to confirm it at garages that could diagnose the problem further than the free test at Auto Zone.

As for the oil changes, I'm with Sulaco on that. I don't go so far as 20,000 to 25,000 miles though, but I used to go to about 11,000 to change with the Mobile 1 synthetic and MB filter (or other good filter brand). I now try to do about 7,000 though; One time I think I did about 15,500 miles since I was working well over 40 hours a week and just didn't have time or energy to get it changed. The car was fine, all was good.

[jc1kz]

Why 10000 miles? Where and who suggested this to you? The most is 6000 miles before you change oil if you are using synthetic oil.

JRE320, no one has suggested it to me, I wait and change it every 10,000 due to I do not use the car that much and even waiting that long to change it the oil is always clean, like not dirty or dark...and the car is never driven hard. Last oil change was May/2012.....

Scary-Larry, I have had the wiring changed in 2009 so it is the newer updated wiring harnes, for all the engine and trany and lights, everything that has/had a harness was changed. I also bought a new MAF but it is not a bosch so I will be getting one and sending this one back....

[Scary-Larry]

I really hope that fixes your problem. Like I said, don't go down the path I went down because I spent over $600 changing all sorts of parts that had to do with the check engine light when it was just the maf sensor. The second time it broke for me I knew what it was, had it changed, and it was all good.

[Sulaco]

Yeah it appears to be luck for some. My maf was only changed once in the 14 years I drove my 94 c280, and I drove that thing like a merciless idiot teenager. Hopefully you will have similar luck.

[JRE320]

n/m

[jc1kz]

I'm sorry about that guys. I should have mind my own business on this simple maintainance and not even my car. Who cares??? right????

JRE320, all input is appreciated...it is just that the topic was oil in #3 & #5 spark plugs, not when do we change the oil....I have read some (not all) of your replies to different member questions, and they are usually very informative. So don't stop replying your experiance is needed here as well as any other members that have knowledge and expertise in helping others to fix their MB W202s... My experiance has only been in driving this fine automobile, and getting advice from my Gramps, (who is not around anymore) hence my joining the fourms, to ask others the how/where and what to do to keep things going. So please do not get offended or upset, if everyone does not agree with sound advise......thank you for all you input....

[JRE320]

n/m

[vaspen]

lol :3 trucker we change our oil evey 60,000 miles XD

off topic sorry lol

but maby the seals went bad under the head were all the valves are ?

[Scary-Larry]

lol :3 trucker we change our oil evey 60,000 miles XD

off topic sorry lol

but maby the seals went bad under the head were all the valves are ?

Wait a minute............ what kind of car do you have? Sulaco changes every 20,000 to 25,000 miles (which is alright only for a Benz and such, but not for other cars), I change between 7,000 and 11,000 miles which is just below what the manual says for my 98 C280, and JRE320 does not take a chance with his engine and changes around 6,000 (his E55 will last forever). I don't mean to come off aggressive....but what do you drive and how many miles are on it? You must drive so careful I imagine?

[vaspen]

FOR WORK i drive a 2011 freightlinner cascadia with a detroit diesel 15 that has 550 hp and 1750 fp-tq
we change that oil every 60,000
in the benz we woud change it every 3000 (come from a family of mechanics >:)

[vaspen]

you have to remember our oil is like thicker than mollases in winter lol

[JRE320]

n/m

[Scary-Larry]

FOR WORK i drive a 2011 freightlinner cascadia with a detroit diesel 15 that has 550 hp and 1750 fp-tq
we change that oil every 60,000
in the benz we woud change it every 3000 (come from a family of mechanics >:)

That's amazing man. I thought about being a truck driver since I like driving for long periods of time, and the idea is still up in the air. I looked up the truck and it looks really nice. Hope you didn't mind me asking.

What kind of Mercedes Benz do you have by the way?

[W202FTW]

I read somewhere in the fourms here, now I can not remember who had the same issue...just want to know what needs to be done.?
I have a '94 C280 w202 (inline six) My car was suffering from the low idle/would die at stops/like the coils were bad...took it to o'rielly's and got the code P0300 (random misfire) so I bought new spark plugs and a torque wrench, and set off to replace the plugs and coils....removed the plactic MAF air intake (the MAF was good and clean but past the MAF the plastic was smuggie/oily and there was a smaller ??? MAF ??? and it was dirty w/oil) There was a bit of oil going down the throtle body also. So removed the cover for the coils and spark plugs and all looks good, then I remove #1 & #2 plugs they were okay (but did need ro be replaced) then I went in to remove #3 and it had oil on the plug and I guess it dripped down into the cylinder.....cleaned what I could and replaced w/new plug, #4 was okay then #5 also had oil, I did the same cleaned and replaced w/new plugs....(didn't replace any coils) I just replaced the MAF and breather plastic and started the car.....A puff of blue smoke came off the engine area, and every thing worked fine no stalling, it idled just fine too....turned it off and replaced every thing back on the way it should go and started it again and took it for a spin.....(about five miles and back) as I parked it and left it to idled it acted fine....but now I wonder what that smaller (MAF ???) was and where did all that oil come from???? and what to do about that.....I didn't see any oil in the area around the coils and spark plugs untill I removed the #3 & #5 plugs....please advise/help

Thank You,
Steve

There are rubber gaskets ( shaft seals ) in each of the spark plug tubes. Get the valve cover off, and pry off the gaskets with a flathead screw driver. Clean the mounting holes and insert new seals. Normally you wouldn't have to replace the valve cover gasket but while it's off it wouldn't hurt to install a new one.

[vaspen]

as they say cant be too safe :P jre for trucks if we changed oil at 3-6k miles we would be sitting all the time lol i drive 4.5k miles a week haha

[jc1kz]

Hey guys just wanted to post the results/outcome on my Benz.....I finally broke down and took the car in to a Indy for a diagnostics check as I kept replacing the spark plugs/coils/wiring and extensions/MAF any other things that were suggested in here......Well the first Indy place I took it to said that he was hearing a bad sound coming from the timing chain and it could be the guide or pulley? and he needed to also do a compression test.....
I told him to get it off the lift and bring it around and I would pay their $110.00 for their advise....but if I had to do a timing chain and valve guides @ their hourly prices I was better off just buying a used W202 motor and swapping it out.....besides the car started and ran fine if I held the gas pedal down it was just not doing well @ idle it would idle at below 500 and just die.....So two days later I took it to a second Indy shop and also had the guy do a diagnostic evaluation on my Beasty Benz.....(I didn't mention that I had already gotten one from someone else) he told me that the car had an erratic electrical malfunction and he disconnected something on the car, and it ran smoother, but he said he needed to keep it for a few days.....(he did not mention anything about a timing chain or bad compression) or I if I wanted to I could drive it as is and it would be fine (no charge)....so I took it home and drove it for a few miles (75 miles) and it was fine but still not perfect. So I took it back and left it with him to do further checking....two days latter the Indy shop calls me and says the car needs a new ECM as the one in it was acting goofy/erratic.....said it would fix it right up if replaced it, so I said okay just tell me which arm or leg to cut off...he laugh and said not to worry....Well I picked up the car today and it is perfect....it runs great, no stumbling/or low idling/or backfiring the car runs just like it did when I first got it....perfect!!! and it only cost $761.00, no cutting off of any limbs to pay the Indy for fixing my Lil Beasty......I'm soooo glad to have it back and in great running condition, after months of trying to fix it myself, you guys had great responses but this time it really needed a diagnostic check up to fix it......thank you guys......I'm off to do some random driving now......

[Scary-Larry]

I'm really glad it is resolved. It must be such a good feeling to have it running great again; who would ever have guessed it was the ECM?

Good thing you didn't have to give any arms or legs.


Enjoy the ride.

[Sulaco]

Damn, son. I'm glad it was resolved as well. Few things are as rewarding as a properly-functioning M104-powered w202. I have a C43 and very often miss my 1994 C280.

FWIW there's one added benefit to our cars being so old that they are found in junkyards: Long story short, my alternator created a massive power surge that blew out all kinds of electrical crap on my C280. ECU, ABS computer, and a bunch of smaller relays all over the car. I was looking at thousands upon thousands to repair.

Found a 1995 C280 owned by an old man. Head gasket let go and he overheated it. An indy shop bought it to pull random parts they needed (CCU, full exhaust, throttle body). I bought the entire car from them for $450 and swapped out all the electrical components I needed, and STILL had a shitload of spare parts for my C280 and 1994 E320 (also an M104). Ended up using the water pump and alternator. Still had a complete interior, transmission, all body panels. Damn, it was the best $450 I ever spent, but it sure was an eye-sore sitting in my driveway.

[Scary-Larry]

Damn, son. I'm glad it was resolved as well. Few things are as rewarding as a properly-functioning M104-powered w202. I have a C43 and very often miss my 1994 C280.

FWIW there's one added benefit to our cars being so old that they are found in junkyards: Long story short, my alternator created a massive power surge that blew out all kinds of electrical crap on my C280. ECU, ABS computer, and a bunch of smaller relays all over the car. I was looking at thousands upon thousands to repair.

Found a 1995 C280 owned by an old man. Head gasket let go and he overheated it. An indy shop bought it to pull random parts they needed (CCU, full exhaust, throttle body). I bought the entire car from them for $450 and swapped out all the electrical components I needed, and STILL had a shitload of spare parts for my C280 and 1994 E320 (also an M104). Ended up using the water pump and alternator. Still had a complete interior, transmission, all body panels. Damn, it was the best $450 I ever spent, but it sure was an eye-sore sitting in my driveway.

Damn, $450 for a 1995 C280 to use as spare parts. The car paid for itself, nice.