Chetter

I continue to get moisture inside my ignition distributors during high humidity, rain, and even when I wash my 1995 sl500. Obviously the ignition system isn't very fond of such and reacts accordingly. 150 k miles, ran good for several years and now this trouble. Should there be a gasket on the distributors to seal out moisture, is it proper to silicone the cap, ?????.


Has anyone else experienced this problem and how did they solve it?


Would appreciate a solution, suggestion, sympathy, or whatever as long as I can start cruisin' down the highway.

cliffyk

I do not have experience with this issue on SL500s, however I have found the problem of moisture in the distributor just as you describe on other vehicles, and found two somewhat related things that might be at play--they also may not be relevant?

The first is the distributor shaft seal. If not sealing properly crankcase gasses (blow-by) which contain a lot of water vapour can find there way to the distributor and condense.

The second issue that can contribute is the PCV system; if clogged the crankcase can be slightly pressurised, pushing the water vapour into the distributor.

Smell the inside of the cap--if it smells like crankcase vapour one or both of these may be the problem. Colder weather exacerbates all of this...

Chetter

Thanks cliffyk...... your suggestion is certainly a new slant to the subject and very appreciated. I will pursue your idea today and give you feedback as to my success. If I could locate an illustrated parts breakdown it would be a great help. I am very cautious about creating a major problem fooling around with unknowns.

cliffyk

There is supposed to be a sealing ring between the cap and the protective cover (#14)--are those intact?

Chetter

Thanks for the info...... I have ordered 2 each and should have them next Tuesday........ that's the way it is when you live "down in the boondocks"!

Chetter

cliffyk.............. you was on the money with the seal ring. Would you mind devoting a little time to helping me solve my quick flashing turn-signals. All turn signals flash when called on however, the "lamp out" light on the dash comes on which indicates indicating that a bulb is out somewhere in the car.


I have worked on this problem for more than a year and still cannot cure the problem. I have replaced all light bulbs with Mercedes bulbs.


The Mercedes shop supervisor still tells me that there is a light out somewhere. The owners manual states that the "lamp out" light comes on when lights are actuated indicating there is a bulb out in which ever system was activated.

cliffyk

If the high wattage filament in one (or both) of the front dual-filament lamps fails; or if the socket contact is dirty/corroded; the lamp monitor will flash the low wattage "parking" lamp filament so that some sort of signal appears.

Check that the bright filaments are flashing...

cliffyk

Double posted for some reason?

Chetter

That's an amazing thought. I know that when I installed all new light bulbs, those double element bulbs were keyed or slotted to be inserted only a certain way. I recall that some of them, and I think they were on the rear of the car, would not make electrical contact if I attempted to rotate them 180 degrees. When this bloody rain and frigid miserable weather turns sunny and bright ....... then I can check this suggestion by cliffyk out. Will keep you posted. Chet sends

cliffyk

There are some lamps used in the rear that have 135° offset pins rather than the 180° offset we "Yanks" (my mum was a Brit war bride) are more familiar with; however I do not believe they are used the the rear turn signals. I would first check the front signals as they use plain 'ol 1157 type lamps.

I experienced the same issue you describe just after getting my '98 (on July 1 of last year). For me it was the left (driver's side for LHD) socket that was slightly corroded; I noticed it because the left turn signal was dimmer than the right...

Chetter

cliffyk ..... re: moisture in distributor. I obtained two seal rings a.k.a. "O" rings from Mercedes dealer. Today I replaced the old ones with the new pretty red ones I purchased. A question has risen! The old previously installed "O" ring was located behind the raised portion on the part # 14. To refrain from removing the rotor I physically pulled the old "O" ring over the raised protruding part around the circumference of part #14. Since I had that experience, I am now concerned if the previous "O" ring was improperly installed and it should be in front, for instance toward the cap end of the distributor, of the raised part of # 14.


I inspected the cap very closely and found what appeared to be arc trails from each of the four contacts inside the cap that were running directly to the center electrode. These trails were not on the surface, for instance I could not rub them off, however from my limited experience they could with the right circumstances provide a path for the ignition spark. I have ordered a replacement cap.


Thank you so very much for your help. If you see things differently or see something I might have missed please let me know.

cliffyk

This (the arc trails) are likely 75 to 90% of the immediate problem, and not at all uncommon in distributor ignition systems--in fact one of the primary problems that caused engineers to work overtime to design distributor-less ignition systems. Once those track occur (often from moisture in the distributor) they only get worse as electricity, particularly high voltage electricity, will seek and follow the least resistive path.

I have never seen the distributors on an early M119 engine, however I have seen scores of such systems on other vehicles. Perhaps someone with direct knowledge of these systems can provide some cogent advice. More often than not fitment of gaskets/seals/etc. follows a very distinct "common sense" approach--do what your gut tells you and you won't be that far off.

As to the caps. yes they need to be replaced. In the "old" days caps and rotors were changed when you changed the plugs and wires (each 18 to 20k miles)--and while you had it open do the points and condenser as well...

Chetter

Thanks once again cliffyk. While waiting for the caps and rotors to arrive I decided to load up the RV motorhome and head out 50 miles to the piney woods of south Mississippi and do "smoking", on the fire pit that is!, burn some hot dogs, do some marshmellows, and lay back and let MB rest.


Speaking of the "old" days, I go back to the Model A and T days..... when we patched tires on the outside, hand cranked the engine, cast out the a.k.a. "big rock"to stop and good gasoline was ten cents per gallon. All this "new fangled fancy stuff" kind of gets a grip on me occasionally, but I keep on plugging along with the help of kind gentlemen like you.

Chetter

re: quick flashing lights..... I did recheck the lamp bulbs and sockets. Watched each bulb flash and the bright element is definitely flashing.


I faintly remember a year that I found a post where the fellow stated that he opened up some box and found an open wire inside. He repaired it, reinstalled the component and all worked well. I have searched to find that post again but have been unsuccessful.


I have been told that my main problem is that I bought the wrong year SL500. Statement was that the 1995 was a "*******" year. I have considered dumping this one and look for a later year model. Who knows...... what the future holds? Not me!

cliffyk

I don't go directly back that far, however I have driven my share of "Ts", a very dear friend has a 1913 (I tell people that it has three pedals and not a damned one of them is the throttle). My father has a '28 Model A Business Coupe that is his pride and joy, and 1953 "Jubilee" model N tractor that replaced his 1942 that was "all worn out"...

Chetter

Is it ok for us to chat on this thread? I'll test the water! ha! I also like "old iron". I have three Farmall Cub tractors.... 1947, 1948 and 1949. I could get into all the implements but my better judgement says "no, better not". I looked back to see where you are located..... couldn't find the answer however, for some strange reason I tend to think it is Kansas. I need to update my garage on the forum. I am also having top hyd cylinders leaking problems but, won't go there on this tread. Those "Jubilees" were some hard working machines.

cliffyk

Why not, it is supposed to be a "forum".

I am in Saint Augustine FL, been here for 23 years after 45 on Cape Cod and environs (with some excursions); my father is West of Ocala FL--he's been there for 40+ years, he will be 90 on May 28.

I actually was in Kansas for a year a long time ago--however we are not in Kansas anymore...

Chetter

cliffyk...... It appears that the distributor cap and rotor have put out the CHECK ENGINE light reflecting a code 7. I am now in Missouri with my 94 year old aunt for about 2 weeks and the Benz is still in Brooklyn, MS. Just giving you some feedback on my progress thus far.
NEXT SUBJECT: Now my CHECK ENGINE light is on with a code 19 set..... converting that to words which means "LH-SFI injector" problems. I don't know what the LH means however, the SFI means SEQUENTIAL FUEL INJECTOR. It runs good when cool, but at idle when hot there is an infrequent "skip" or "bump" or "miss".


Do you have any thoughts about this subject that I can "Be Prepared"... good Boy Scout... to pursue when I return home.

Chetter

cliffyk: Now for the long haul. Even though replacing the "O" rings appears to have cured the moisture problem in the distributors ...... though I haven't exposed the car to moisture.... my perfection mind-set tickles my brain into thinking ....... "how about when I do expose it to moisture "someday"? The thought provocation came when I installed the new "O" rings. That being, should the "O" ring fit into the cap, item 23, cavity or onto the metal ring, item 14? The parts breakdown is not specific and the "O" ring will fit either location. It is difficult to determine which location provides the best moisture sealing and since the old "O" ring was located on the metal ring, item 14, perhaps that was the origin of my moisture/arcing problem. I appreciate you addressing this with me. Chet sends

Poundy

Seal 17 fits on the cap 23. If you have ordered new caps the seals should come with them.

Chetter

Thanks Tas: The new distributor caps I received did not have the seals installed. I obtained the seals from my Benz dealer and installed them as the previous seals were installed..... onto item 14 and pushed up until it stopped at the raised part of item 14..

RA6523

I have been plagued by this problem for years, and several replacements of distributor caps, starting at 25k miles, replaced again at the 60k service...and again later when my mechanic found the caps filled with numerous, and I do mean numerous arc trails. He said he'd never seen a cap with so many, and was surprised it would run.
I thought my condensation problem was the result of rainy and also humid northwest weather, and have tried heavier O-rings, but the condensation returns, and yesterday, at the end of the driest, warmest summer here, the "missing/rough running" has returned.
I love this great highway car which just turned 100K this year.
Into the shop it goes next week.

Dudereeno

Chetter, this post is four years old but those of us who own this SL500 are besieged with this problem. I bought my 94 SL500 when it was only one year old and still own it. I spent three years (and a fortune) trying to fix the problems symptoms. Running rough, lack of power from a standstill, sputtering and sometimes stalling during a quick start - all very intermittent and with no reasonable explanation. Finally after replacing the ignition control module ($4000 for the part and it didn't fix the problem - which the dealer assured me it would fix it), many wiring and electrical components - someone discovered the moisture in the distributor. Of course, if you go through a high pressure wash - it reoccurs, if it rains and you run through mud puddles it might happen. It's a major pain in the ***, but simply blowing out the moisture seems to be a cheap and useful solution (until the next time)

Chetter

Cliffyk........... I am still contending with the moisture in distributors. I would like to check out the pcv system but can't locate a diagram or parts picture of where the parts are located. Can you assist me. Chetter sends