I have a 95 E320 wagon which I purchased almost 2 years ago. The car has been great. Over the past few months I have noticed an intermittent sulfur smell coming from the car when I park (maybe I can't smell it while driving). It only happens occasionally and I can't say if it happens when I drive hard. I have done a search in the archives and noticed a lot of people saying it could be the cat. I just did a smog check here in California and it passed so hopefully it's not the cat (the mechanic told me if it's the cat, it could run a few thousand dollars!!!). Also in doing my search, I found that it is common for the W124 to get around the mid-20's for MPG. I have always averaged the low 20's so I am concerned about something maybe not running right and it could be related to the sulfur smell?

So my questions:
1. For those owners of similar E320 wagons, what is the average MPG you get?
2. Should I try some other less expensive repairs before diving in to change the catalytic converter?
3. Will it harm the engine if I just ignore the smell and live with it? Especially since I passed the smog check, I would think emissions are acceptable.

Any comments, suggestions, etc. would be greatly appreciated.

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Benson

1995 E320 Wagon
1996 Volvo 850GLT

I'm going to answer your questions with more questions.

1. When was the last tune-up ?
2. Have you tried switching brands of fuel ?
3. When was the last time the O2 sensor was changed, or at least scrutinized ?

Changing the cat is the absolute last option !

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2007 C 230 Sport.

To answer your questions:

1. I just brought the car in for an oil change and front pads and rotors a couple of weeks ago. Before that, was probably in November for a 75k mile tuneup.

2. The fuel I use varies but I mostly use Valero here in the SF Bay Area.

3. I can't say when the O2 sensor was checked. I just bought the car almost 2 years ago and have not had a "major" tuneup on it yet. The next big one will be 90k.

I used to do maintenance on my own cars but in my old age (35), I just send the car out to an independent MB garage that comes highly recommended by a friend. I would be willing to try changing the O2 sensor if it's pretty easy to do.

Thanks.

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Benson

1995 E320 Wagon
1996 Volvo 850GLT

My guess is that your O2 sensor is fine. If it was bad, you'd not only get a check engine light, but your gas mileage will also drop like a rock. I don't know any owner of a 1993-1995 E320 who gets better than an average in the low 20's.

My guess is that your cat might be getting close to replacement. You may have passed smog, but it could still be not functioning like it used to be.

I believe an original cat at the dealer is about $1,800, but there are after market cats just as good that are half as much.

I had mine replaced for less than $1,000.

www.timevalve.com sells cats that are made to OE quality. They are a frequent advertiser in the Star Magazine.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

I've got a '94 wagon that gets ~20 mpg in the winter and ~24 mpg in the summer, all highway too. The smell you describe is one that I've smelled too around my car sometimes after shutting it off. It is not consistent though. Could it be the seasonal gasoline quality? BTW, my wagon has 197,000 on it and oil that has the same color as honey after 3,000 miles.
Have you had the head gasket and wiring harness changed yet on your car?

DTF,

I can't say that I know if the head gasket and wiring harness have been changed. Since I have owned the car, I haven't done it. Are these known issues with these cars that they need to be replaced at some point?

Thanks.

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Benson

1995 E320 Wagon
1996 Volvo 850GLT

Sulpher smell is usually the catalitic converter clogging....

I suggest a very specific search (so as not to get 1,000 hits) on this forum, on those two issues. Other things that commonly go are the fan clutch bearing at 200,000 miles, OVP relay...Other guys with W124s around here are much more educated about these cars than me so do the search and plan for these one time fixes. The car is worth it (in my opnion).

Yes, the engine wiring harensses on 1993-1995 E320's are all bad. Do a search on "wiring harness".

The original head gaskets also had a bad design, and leak oil externally at the right rear corner of the head gasket (passenger side).

Yours has probably been replaced if it's not leaking now as the original head gasket probably couldn't make it this long.

The good news is that the new wiring harnesses are good, and the new head gaskets don't leak.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Hello everyone! First time poster; have been lurking for a few months now ever since I bought my 1995 E320 wagon in Feb 03. I had to post on this one, as I experienced exactly the same thing, and fixed it!
My car had 53K miles when I got it; all was perfect except for the sulfur smell and miserable mileage (worst tankful was 13 mpg 70/30 in-town/highway, best was 20 mpg, not too bad, but ALL highway 300 miles). The car ran really well; nice idle, good acceleration, etc. Just stunk! Took the car to the dealership for full inspection right after purchase, the mechanic noticed the smell as well and said he could not get reliable diagnostic read from computer because "too many things were reading incorrectly". He said I needed the HFM wiring harness, $805 for my car their price, plus 3.5 hours labor @$90/hr. Cha-ching!
Did some searching on this site, and it turns out there are two different part numbers for our car for the harness, depending on date of manufacture. The part number can be found on the harness behind the battery (you may or may not need to remove the battery to see the number, just check along the side of the battery for a thick bundle of wires with a large white tag on it. The tag has bot the part number and date of manufacture (convenient!) stamped on it. Be careful not to manipulate the wires too much, for if they are anything like mine were, they are very brittle and too much movement can cause a shorting out situation. I recall that my part number ended with 29 33, sorry I'm not more help here but I'm on vacation and have nothing in front of me to see my number. Do a search and you'll find lots of info.
This particular number harness is one of the more expensive ones if not the most expensive. I got mine from Fastlane for $675. Put it in myself over 3h. I change fluids on my cars, not much more, and this job was relatively easy. You do have to be a contortionist to get a few of the connections, but it's not impossible. If you want more info on how to do this, either do a search or just let me know. All the info is already on this site in the archives.
Long story a bit shorter: My worst mileage has been 18 mpg mostly in-town driving, my best was last weekend 90% highway and 25 mpg. Sulfur smell eliminated completely! Runs the same as before! Pulled apart some of the old harness and the insulation on the wires was cracked every 5-10mm, but only on the parts of the harness that saw the most heat from the engine.
Maybe yours is bad? Sorry this was so long!

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Brian
1995 E320 wagon

I have a 1995 E320 Wagon with only 41k miles on it, and it averages 24mpg on the highway and around 19 or 20 in town. Really. As for the smell, I notice it occasionally when under hard acceleration up long hills, same as in my other cars, but usually never at any other times. So far so good with mine. By the way, I noticed you have a Volvo as well...I have a 1996 960 wagon in addition to the Benz. Which do you like better, just out of curiosity?

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2002 Mercedes-Benz E320 4Matic
1995 Mercedes-Benz E320 Wagon
2005 Land Rover LR3 V8 SE
1999 Audi A8 4.2L quattro

I get the sulfur smell on occasion as well, I tend to think it has a lot to do with the gasoline that's used. No sulphur smell whatsoever using AMOCO or EXXON, but when I fill up at BJ's it's almost a certainty that it will stink awful. It usually hits me when I pull into my garage.........It hasn't stopped me from using BJ's fuel but I've narrowed it down to fuel types with my E320.

Anyone else experienced the same thing using BJ's fuel? I haven't had any running problems using their fuel, just very stinky!!

W124 is a solid car, one of the best chasis ever made. Classic, ageless design. It does require a little more attention than some other cars.

Following are the week area's and approx. prices at MB dealerships:

Engine Wiring Harness ($800)
Engine Head Gasket ($2200)
OVP Relay
Fuel Pump Relay
EGR Valve
AC Evaporator ($3000)

Major engine components may last over 300,000 miles with routine maint.

I get around 20 mpg and no unusual smell.

I would recommend keeping a backup OVP and fuel pump relay in the car. Also, you can make a led/sw tool to check the codes for the various modules like the ECM etc.

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Zafar
94 E320 58000 Miles

I appreciate all the responses. Since I originally posted this topic, I have changed my engine wiring harness and I have not noticed any more sulfur smell in the 3-4 weeks since doing it.

Coincidentally, I had an unrelated problem a few days after swapping out the harness in that the car would not start, even though it ran fine for a couple of days. After bringing it to my indie mechanic here, it turned out to be the fuel pumps (there are 2 of them!). $600 later, the car is now running fine.

I have just purchased a keyless entry kit from Commando Alarms and I'm hoping to do that this weekend. Thanks to this forum for the valuable information about my car, I feel really good about my purchase and about doing the necessary maintenance to keep it running.

TROVERMAN: To answer your question about the Volvo. Our previous cars before the Volvo were a Honda Accord and a Ford Escort. Don't knock the Escort, it was actually one of the best cars we've ever owned in terms of reliability and minimal cost of maintenance. When we got the Volvo, I thought wow, what a solid and quiet car. Now after getting the MB wagon, I feel that the MB is a much more solid car with even no squeaks or rattles anywhere. I enjoy driving both because they each have a different feel, especially after putting in Koni shocks/struts in the Volvo. The Volvo feels a lot lighter and can launch off the line a little quicker (maybe because the gas pedal is lighter) and it can handles turns very well with the Koni's in there. My wife and I like both cars and the main reason for those choices is safety. I don't think you can beat MB and Volvo for solid build and safety they offer their occupants.

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Benson

1995 E320 Wagon
1996 Volvo 850GLT

The sulpher smell has NOTHING TO DO WITH the cat or the O2 or the wiring, it is the elemental sulpher in high sulfer, poor quality crude oil that remains as it is refined into gasoline.

As it ( sulfer) passes though the cat, which stores O2, the heat helps the reaction from Sulfer to Sulfer Dioxide go, Sulfer dioxide smells like rotten eggs, or to some people like a fart.